4,848,485 Shares of Common Stock
Warrants to Purchase 2,181,818 Shares of Common Stock

We are offering up to 4,848,485 shares of our common stock and warrants to purchase up to 2,181,181 shares of our common stock directly to one or more investors. Each investor will receive a warrant to purchase 45 shares of our common stock, at an exercise price of $2.00 per share, for every 100 shares of our common stock purchased. As the warrants may be exercised only by "cashless exercise," we will not receive any additional proceeds upon exercise of the warrants. This prospectus supplement also covers the offer and sale of the shares of common stock issuable upon exercise of the warrants offered hereby.

Our common stock is traded on the Nasdaq National Market under the symbol "SATC." On December 20, 2004, the last reported sale price of our common stock on Nasdaq was $1.82 per share.

Investing in our securities involves a high degree of risk. See "Risk Factors" beginning on page S-3 of this prospectus supplement.

	Per Share
Offering Price	$	1.6500	$	8,000,000
Estimated transaction fees	$	0.1093	$	530,000
Estimated net proceeds to SatCon	$	1.5407	$	7,470,000

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

		Page
About this Prospectus Supplement		S-2
Special Statement Regarding Forward-Looking Information		S-2
Risk Factors		S-3
The Offering		S-12
Use of Proceeds		S-12
Description of Common Stock		S-12
Description of Warrants		S-12
Plan of Distribution		S-13
Legal Matters		S-13

This prospectus supplement and the accompanying prospectus is part of a registration statement that we have filed with the Securities and Exchange Commission utilizing a "shelf" registration process. Under this shelf process, we are offering to sell shares of our common stock, warrants to purchase shares of our common stock and shares of common stock issuable upon exercise of the warrants using this prospectus supplement and the accompanying prospectus. The prospectus supplement describes the specific terms of the common stock and warrants offering. The accompanying base prospectus gives more general information, some of which may not apply to this offering. You should read both this prospectus supplement and the accompanying prospectus. If the description of the offering varies between the prospectus supplement and the accompanying prospectus, you should rely on the information in this prospectus supplement.

You should rely only on the information provided or incorporated by reference in this prospectus supplement and the accompanying prospectus. We have not authorized anyone to provide you with different or additional information. You should not assume that the information in this prospectus supplement or the accompanying prospectus is accurate as of any date other than their respective dates, regardless of the time of delivery of this prospectus supplement and the accompanying prospectus or any sale of common stock or issuance of warrants. Our business, financial condition, results of operations and prospects may have changed since those dates.

You should not consider this prospectus supplement or the accompanying prospectus to be an offer or solicitation relating to the securities in any jurisdiction in which such an offer or solicitation relating to the securities is not authorized. Furthermore, you should not consider this prospectus supplement or the accompanying prospectus to be an offer or solicitation relating to the securities if the person making the offer or solicitation is not qualified to do so, or if it is unlawful for you to receive such an offer or solicitation.

Unless the context otherwise requires, references in this prospectus supplement and the accompanying prospectus to "SatCon," "we," "us," "our" or similar terms refer to SatCon Technology Corporation and its subsidiaries.

This prospectus supplement and the accompanying prospectus include and incorporate forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements, other than statements of historical facts, included or incorporated in this prospectus supplement and the accompanying prospectus regarding our strategy, future operations, financial position, future revenues, projected costs, prospects, plans and objectives of management are forward-looking statements. The words "anticipates," "believes," "estimates," "expects," "intends," "may," "plans," "projects," "will," "would" and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. We cannot guarantee that we actually will achieve the plans, intentions or expectations disclosed in our forward-looking statements and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. We have included important factors in the cautionary statements included or incorporated in this prospectus supplement and the accompanying prospectus, particularly under the heading "Risk Factors," that we believe could cause actual results or events to differ materially from the forward-looking statements that we make. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make. We do not assume any obligation to update any forward-looking statements.

Before you invest in our securities, you should be aware that there are various risks, including those described below. You should consider carefully these risk factors together with all of the information included or incorporated by reference in this prospectus supplement and the accompanying prospectus before you decide whether to invest in our securities. This section includes or refers to forward-looking statements; you should read the explanation of the qualifications and limitations on such forward-looking statements discussed elsewhere in this prospectus supplement and the accompanying prospectus.

We have a history of operating losses, may not be able to achieve profitability and may require additional capital in order to sustain our businesses.

For each of the past ten fiscal years, we have experienced losses from operating our businesses. As of September 30, 2004, we had an accumulated deficit of approximately $127.7 million. During the fiscal year ended September 30, 2004, we had a loss from operations of approximately $4.0 million. If we are unable to operate on a cash flow breakeven basis during 2005, we may need to raise additional capital in order to sustain our operations. There can be no assurance that we will be able to achieve such results or to raise such funds if they are required.

Our financial statements for our fiscal year ended September 30, 2003, which are included in our Annual Report on Form 10-K, contain an audit report from Grant Thornton LLP. The audit report contains a going concern qualification, which raises substantial doubt with respect to our ability to continue as a going concern. The audit report relating to our financial statements for our fiscal year ending September 30, 2004 will likely contain a going concern qualification as well. The receipt of a going concern qualification may create a concern among our current and future customers and vendors as to whether we will be able to fulfill our contractual obligations.

We could issue additional common stock, which might dilute the book value of our common stock.

We have authorized 50,000,000 shares of our common stock, of which 28,332,210 shares were issued and outstanding as of December 15, 2004. An additional 4,848,485 shares of our common stock will be issued in connection with this offering. Our board of directors has the authority, without action or vote of our stockholders in most cases, to issue all or a part of any authorized but unissued shares. Such stock issuances may be made at a price that reflects a discount from the then-current trading price of our common stock. In addition, in order to raise the capital that we may need at today's stock prices, we will need to issue securities that are convertible into or exercisable for a significant amount of our common stock. These issuances would dilute your percentage ownership interest, which will have the effect of reducing your influence on matters on which our stockholders vote, and might dilute the book value of our common stock. You may incur additional dilution of net tangible book value if holders of stock options, whether currently outstanding or subsequently granted, exercise their options or if warrant holders exercise their warrants to purchase shares of our common stock.

The sale or issuance of a large number of shares of our common stock could depress our stock price.

As of December 15, 2004, we have reserved 5,342,668 shares of common stock for issuance upon exercise of stock options and warrants, 1,131,120 shares for future issuances under our stock plans and 197,905 shares for future issuances as matching contributions under our 401(k) plan. We have also reserved 850,000 shares of common stock for issuance upon conversion of the outstanding Series B Preferred Stock, which can be converted at any time. As of December 15, 2004, holders of warrants and options to purchase an aggregate of 3,628,690 shares of our common stock may exercise those securities and transfer the underlying common stock at any time subject, in some cases, to Rule 144. In connection with this offering, we are issuing warrants to purchase an additional 2,181,818 shares of our

common stock. These warrants are immediately exercisable and, upon exercise, the underlying common stock may be transferred at any time subject, in some cases, to Rule 144.

There is no market for the warrants and we do not expect an active market for the warrants to develop.

There is no market for the warrants being offered hereby and none is expected to develop after this offering. We are no required, and have no plans, to list the warrants on a securities exchange or automatic quotation system. We expect that there will be a limited number of holders of the warrants after this offering. In the absence of a market, holders of the warrants will likely find it difficult to sell warrants expeditiously, at favorable prices or at all.

The value of the warrants is derived from and dependent on the value of our common stock.

An investment in the warrants is highly speculative, and the warrants may not maintain any significant value in the future. The value of the warrants will be indirectly derived from the value of the shares of common stock underlying the warrants, and the value of the warrants and the underlying shares of common stock may be adversely affected by a number of factors beyond our control, as more fully described under the other risk factors discussed in this prospectus supplement and the accompanying prospectus.

We have not consistently complied with Nasdaq's Marketplace rules for continued listing, which exposes us to the risk of delisting from the Nasdaq National Market.

Our stock is listed on the Nasdaq National Market, which affords us an opportunity for relatively broad exposure to a wide spectrum of prospective investors. As a requirement of continued inclusion in the Nasdaq National Market, SatCon must comply with Nasdaq's Marketplace Rules. In 2003, SatCon received notice from Nasdaq that it was not in compliance with Marketplace Rules. Subsequently, in late 2003, Nasdaq advised SatCon that it had achieved compliance, and SatCon has continued to maintain compliance with the Nasdaq National Market Marketplace Rules for Continued Inclusion since that time. However, if we fail to maintain compliance with these rules and our common stock is delisted from the Nasdaq National Market, there could be a number of negative implications, including reduced liquidity in our common stock as a result of the loss of market efficiencies associated with the Nasdaq National Market, the loss of federal preemption of state securities laws, the potential loss of confidence by suppliers, customers and employees, as well as the loss of analyst coverage and institutional investor interest, fewer business development opportunities and greater difficulty in obtaining financing.

We expect to generate a significant portion of our future revenues from sales of our power control products and cannot assure market acceptance or commercial viability of our power control products.

We intend to continue to expand development of our power control products. We cannot assure you that potential customers will select SatCon's products to incorporate into their systems or that our customers' products will realize market acceptance, that they will meet the technical demands of their end users or that they will offer cost-effective advantages over existing products. Our marketing efforts have included development contracts with several customers and the targeting of specific market segments for power and energy management systems. We cannot know if our commercial marketing efforts will be successful in the future. Additionally, we may not be able to develop competitive products, our products may not receive market acceptance, and we may not be able to compete profitably in this market, even if market acceptance is achieved. If our products do not gain market acceptance or achieve commercial viability, we will not attain our anticipated levels of profitability and growth.

If we are unable to maintain our technological expertise in design and manufacturing processes, we will not be able to successfully compete.

We believe that our future success will depend upon our ability to develop and provide products that meet the changing needs of our customers. This requires that we successfully anticipate and respond to technological changes in design and manufacturing processes in a cost-effective and timely manner. As a result, we continually evaluate the advantages and feasibility of new product design and manufacturing processes. We cannot, however, assure you that our process improvement efforts will be successful. The introduction of new products embodying new technologies and the emergence of shifting customer demands or changing industry standards could render our existing products obsolete and unmarketable, which would have a significant impact on our ability to generate revenue. Our future success will depend upon our ability to continue to develop and introduce a variety of new products and product enhancements to address the increasingly sophisticated needs of our customers. We may experience delays in releasing new products and product enhancements in the future. Material delays in introducing new products or product enhancements may cause customers to forego purchases of our products and purchase those of our competitors.

We are heavily dependent on contracts with the U.S. government and its agencies or from subcontracts with the U.S. government's prime contractors for revenue to develop our products, and the loss of one or more of our government contracts could preclude us from achieving our anticipated levels of growth and revenues.

Our ability to develop and market our products is dependent upon maintaining our U.S. government contract revenue and research grants. Many of our U.S. government contracts are funded incrementally on a year-to-year basis. Approximately 50% of our revenue during fiscal year 2004 was derived from government contracts and subcontracts. Changes in government policies, priorities or programs that result in budget reductions could cause the government to cancel existing contracts or eliminate follow-on phases in the future which would severely inhibit our ability to successfully complete the development and commercialization of our products. In addition, there can be no assurance that, once a government contract is completed, it will lead to follow-on contracts for additional research and development, prototype build and test or production. Furthermore, there can be no assurance that our U.S. government contracts or subcontracts will not be terminated or suspended in the future. In the event that any of our government contracts are terminated for cause, it could significantly affect our ability to obtain future government contracts, which could seriously harm our ability to develop our technologies and products.

Our contracts with the U.S. government are subject to audit by the Defense Contract Audit Agency and other agencies of the government, which may challenge our treatment of direct and indirect costs and reimbursements, resulting in a material adjustment and adverse impact on our financial condition.

The accuracy and appropriateness of our direct and indirect costs and expenses under our contracts with the U.S. government are subject to extensive regulation and audit by the Defense Contract Audit Agency or by other appropriate agencies of the U.S. government. These agencies have the right to challenge our cost estimates or allocations with respect to any such contract. Additionally, substantial portions of the payments to us under U.S. government contracts are provisional payments that are subject to potential adjustment upon audit by such agencies. Adjustments that result from inquiries or audits of our contracts could have a material adverse impact on our financial condition or results of operations.

Since our inception, we have not experienced any material adjustments as a result of any inquiries or audits, but there can be no assurance that our contracts will not be subject to material adjustments in the future.

The U.S. government has certain rights relating to our intellectual property.

Many of our patents are the result of inventions made under U.S. government-funded research and development programs. With respect to any invention made with government assistance, the government has a nonexclusive, nontransferable, irrevocable, paid-up license to use the technology or have the technology employed for or on behalf of the U.S. government throughout the world. Under certain conditions, the U.S. government also has "march-in rights," which enable the U.S. government to require us to grant a nonexclusive, partially exclusive, or exclusive license in any field of use to responsible applicants, upon terms that are reasonable under the circumstances.

Our business could be adversely affected if we are unable to protect our patents and proprietary technology.

As of December 15, 2004, we held 70 U.S. patents and had 2 patent applications pending with the U.S. Patent and Trademark Office. We have also obtained corresponding patents in the rest of North America, Europe, and Asia for many of these patents. The expiration dates of our patents range from 2009 to 2021, with the majority expiring after 2015. As a qualifying small business from our inception to date, we have retained commercial ownership rights to proprietary technology developed under various U.S. government contracts and grants.

Our patent and trade secret rights are of significant importance to us and to our future prospects. Our ability to compete effectively against other companies in our industry will depend, in part, on our ability to protect our proprietary technology and systems designs relating to our products. Although we have attempted to safeguard and maintain our proprietary rights, we do not know whether we have been or will be successful in doing so. Further, our competitors may independently develop or patent technologies that are substantially equivalent or superior to ours. No assurance can be given as to the issuance of additional patents or, if so issued, as to their scope. Patents granted may not provide meaningful protection from competitors. Even if a competitor's products were to infringe patents owned by us, it would be costly for us to pursue our rights in an enforcement action and there can be no assurance that we would be successful in enforcing our intellectual property rights. Because we intend to enforce our patents, trademarks and copyrights and protect our trade secrets, we may be involved from time to time in litigation to determine the enforceability, scope and validity of these rights. This litigation could result in substantial costs to us and divert resources from operational goals. In addition, effective patent, trademark, service mark, copyright and trade secret protection may not be available in every country where we operate or sell our products.

We may not be able to maintain confidentiality of our proprietary knowledge.

In addition to our patent rights, we also rely on treatment of our technology as trade secrets through confidentiality agreements, which all of our employees are required to sign, assigning to us all patent rights and other intellectual property developed by our employees during their employment with us. Our employees have also agreed not to disclose any trade secrets or confidential information without our prior written consent. We also rely on non-disclosure agreement to protect our trade secrets and proprietary knowledge. These agreements may be breached, and we may not have adequate remedies for any breach. Our trade secrets may also be known without breach of these agreements or may be independently developed by competitors. Failure to maintain the proprietary nature of our technology and information could harm our results of operations and financial condition by reducing or eliminating our technological advantages in the marketplace.

Others may assert that our technology infringes their intellectual property rights.

are unsuccessful in defending any claims of infringement, we may be forced to obtain licenses or to pay royalties to continue to use our technology. We may not be able to obtain any necessary licenses on commercially reasonable terms or at all. If we fail to obtain necessary licenses or other rights, or if these licenses are costly, our operating results may suffer either from reductions in revenues through our inability to serve customers or from increases in costs to license third-party technologies.

Our success is dependent upon attracting and retaining highly qualified personnel and the loss of key personnel could significantly hurt our business.

To achieve success, we must attract and retain highly qualified technical, operational and executive employees. The loss of the services of key employees or an inability to attract, train and retain qualified and skilled employees, specifically engineering, operations and business development personnel, could result in the loss of business or could otherwise negatively impact our ability to operate and grow our business successfully.

In the past, we have faced limited competition in providing research services, prototype development and custom and limited quantity manufacturing. We expect competition to intensify greatly as commercial applications increase for our products under development. Many of our competitors and potential competitors are well established and have substantially greater financial, research and development, technical, manufacturing and marketing resources than we do. Some of our competitors and potential competitors are much larger than we are. If these larger competitors decide to focus on the development of distributed power and power quality products, they have the manufacturing, marketing and sales capabilities to complete research, development and commercialization of these products more quickly and effectively than we can. There can also be no assurance that current and future competitors will not develop new or enhanced technologies perceived to be superior to those sold or developed by us. There can be no assurance that we will be successful in this competitive environment.

We are dependent on third-party suppliers for the supply of key components for our products.

On occasion, we agree to fixed price engineering contracts in our Applied Technology Division, which exposes us to losses.

Most of our engineering design contracts are structured on a cost-plus basis. However, on occasion we have entered into fixed price contracts, which may expose us to loss. A fixed priced contract, by its very nature, requires cost estimates during the bidding process and throughout the contract, as the program proceeds to completion. Depending upon the complexity of the program, the estimated completion costs could change frequently and significantly during the course of the contract. We regularly involve the appropriate people on the program and finance staffs to arrive at a reasonable estimate of the cost to complete. However, due to unanticipated technical challenges and other factors, there is the potential for substantial cost overruns in order to complete the contract in accordance with the contract specifications. Currently we have only two significant contracts of this type. During the fiscal year ended September 30, 2004, we have recorded losses on these contracts of approximately $0.9 million.

If we experience a period of significant growth or expansion, it could place a substantial strain on our resources.

If our power control products are successful in achieving rapid market penetration, we may be required to deliver large volumes of technically complex products or components to our customers on a timely basis at reasonable costs to us. We have limited experience in ramping up our manufacturing capabilities to meet large-scale production requirements and delivering large volumes of our power control products. If we were to commit to deliver large volumes of our power control products, we cannot assure you that we will be able to satisfy large-scale commercial production on a timely and cost-effective basis or that such growth will not strain our operational, financial and technical resources.

Our business exposes us to potential product liability claims, which are inherent in the manufacturing, marketing and sale of our products, and we may face substantial liability for damages resulting from the faulty design or manufacture of products or improper use of products by end users. We currently maintain a moderate level of product liability insurance, and there can be no assurance that this insurance will provide sufficient coverage in the event of a claim. Also, we cannot predict whether we will be able to maintain such coverage on acceptable terms, if at all, or that a product liability claim would not harm our business or financial condition. In addition, negative publicity in connection with the faulty design or manufacture of our products would adversely affect our ability to market and sell our products.

We are subject to a variety of environmental laws that expose us to potential financial liability.

Our operations are regulated under a number of federal, state and foreign environmental and safety laws and regulations that govern, among other things, the discharge or release of hazardous materials into the air and water as well as the handling, storage and disposal of these materials. These laws and regulations include the Clean Air Act, the Clean Water Act, the Resource, Conservation and Recovery Act, and the Comprehensive Environmental Response, Compensation and Liability Act, as well as analogous state and foreign laws. Because we use hazardous materials in certain of our manufacturing processes, we are required to comply with these environmental laws. In addition, because we generate hazardous wastes, we, along with any other person who arranges for the disposal of our wastes, may be subject to potential financial exposure for costs associated with an investigation and remediation of sites at which we have arranged for the disposal of hazardous wastes if those sites become contaminated and even if we fully comply with applicable environmental laws. If we were found to be a responsible party, we could be held jointly and severably liable for the costs of remedial actions. To date, we have not been cited for any improper discharge or release of hazardous materials.

Businesses and consumers might not adopt alternative distributed power solutions as a means for obtaining their electricity and power needs.

On-site distributed power generation solutions, such as fuel cell, photovoltaic and wind turbine systems, which utilize our products, provide an alternative means for obtaining electricity and are relatively new methods of obtaining electrical power that businesses may not adopt at levels sufficient to grow this part of our business. Traditional electricity distribution is based on the regulated industry model whereby businesses and consumers obtain their electricity from a government regulated utility. For alternative methods of distributed power to succeed, businesses and consumers must adopt new purchasing practices and must be willing to rely upon less upon traditional means of purchasing electricity. We cannot assure you that businesses and consumers will choose to utilize on-site distributed power at levels sufficient to sustain our business in this area. The development of a mass market for our products may be impacted by many factors which are out of our control, including:

If a mass market fails to develop or develops more slowly than we anticipate, we may be unable to recover the losses we will have incurred to develop these products.

Our quarterly operating results are subject to fluctuations, and if we fail to meet the expectations of securities analysts or investors, our share price may decrease significantly.

Our annual and quarterly results may vary significantly depending on various factors, many of which are beyond our control. Because our operating expenses are based on anticipated revenue levels, our sales cycle for development work is relatively long and a high percentage of our expenses are fixed for the short term, a small variation in the timing of recognition of revenue can cause significant variations in operating results from quarter to quarter. If our earnings do not meet the expectations of securities analysts or investors, the price of our stock could decline.

Provisions in our charter documents and Delaware law may delay, deter or prevent the acquisition of SatCon, which could decrease the value of your shares.

Some provisions of our certificate of incorporation and bylaws may delay, deter or prevent a change in control of SatCon or a change in our management that you, as a stockholder, may consider favorable. These provisions include:

In addition, Section 203 of the Delaware General Corporation Law and provisions in some of our stock incentive plans may delay, deter or prevent a change in control of SatCon. Those provisions serve to limit the circumstances in which a premium may be paid for our common stock in proposed transactions, or where a proxy contest for control of our board may be initiated. If a change of control or change in management is delayed, deterred or prevented, the market price of our common stock could suffer.

We are subject to stringent export laws and risks inherent in international operations.

We market and sell our products and services both inside and outside the United States. We are currently selling our products and services throughout North America and in certain countries in South America, Asia, Canada and Europe. Certain of our products are subject to the International Traffic in Arms Regulations (ITAR) 22 U.S.C 2778, which restricts the export of information and material that may be used for military or intelligence applications by a foreign person. Additionally, certain products of ours are subject to export regulations administered by the Department of Commerce, Bureau of Industry Security, which require that we obtain an export license before we can export certain products or technology. Failure to comply with these laws could result in enforcement responses by the government, including substantial monetary penalties, denial of export privileges, debarment from government contracts and possible criminal sanctions.

Revenue from sales to our international customers for our fiscal years ended September 30, 2004 and 2003 were $3.7 million and $3.3 million, respectively. Our success depends, in part, on our ability to expand our market for our products and services to foreign customers and our ability to manufacture products that meet foreign regulatory and commercial requirements. We have limited experience developing and manufacturing our products to comply with the commercial and legal requirements of international markets. We face numerous challenges in penetrating international markets, including unforeseen changes in regulatory requirements, export restrictions, fluctuations in currency exchange rates, longer accounts receivable cycles, difficulties in managing international operations, and the challenges of complying with a wide variety of foreign laws.

You are unlikely to be able to exercise effective remedies against Arthur Andersen LLP, our former independent public accountants.

Although we have dismissed Arthur Andersen LLP as our independent public accountants and have engaged Grant Thornton LLP, our financial statements for the fiscal year ended September 30, 2001, which are incorporated by reference into this prospectus supplement and the accompanying prospectus, were audited by Arthur Andersen. On March 14, 2002, Arthur Andersen was indicted on federal obstruction of justice charges arising from the government's investigation of Enron Corporation. On June 15, 2002, a jury in Houston, Texas found Arthur Andersen guilty of these federal obstruction of justice charges. In light of the jury verdict and the underlying events, Arthur Andersen subsequently substantially discontinued operations and dismissed essentially its entire workforce. You are therefore unlikely to be able to exercise effective remedies or collect judgments against Arthur Andersen. In addition, Arthur Andersen has not consented to the inclusion of its report in this prospectus supplement and the accompanying prospectus, and the requirement to file its consent has been dispensed with in reliance on Rule 437a promulgated under the Securities Act of 1933. Because Arthur Andersen has not consented to the inclusion of its report in this prospectus supplement and the accompanying prospectus, you will not be able to recover against Arthur Andersen under Section 11 of the Securities Act for any untrue statement of a material fact contained in the financial statements audited by Arthur Andersen or any omissions to state a material fact required to be stated in those financial statements.

To the extent our customers do not advance us sufficient funds to finance our costs during the execution phase of our contracts, we are exposed to the risk that they will be unable to accept delivery or that they will be unable to make payment at the time of delivery. Occasionally, we accept the risk of dealing with thinly financed entities. We attempt to mitigate this risk by seeking to negotiate more timely progress payments and utilizing other risk management procedures.

Our agreement with Silicon Valley Bank subjects us to various restrictions, which may limit our ability to pursue business opportunities.

Our accounts receivable financing agreement subjects us to various restrictions on our ability to engage in certain activities without the prior written consent of the bank, including, among other things, our ability to:

The agreement also subjects us to various financial and other covenants with which we must comply on an ongoing or periodic basis. The financial covenant requires us to maintain a minimum

level of tangible net worth, as defined, which varies from month to month. If we violate this or any other covenant, any outstanding debt under this agreement could become immediately due and payable, the bank could proceed against any collateral securing indebtedness and our ability to borrow funds in the future may be restricted or eliminated. These restrictions may also limit our ability to pursue business opportunities or strategies that we would otherwise consider to be in the best interests of the company.

The holders of our Series B Preferred Stock are entitled to receive liquidation payments in preference to the holders of our common stock.

As of December 15, 2004, 425 shares of our Series B Preferred Stock were outstanding. Pursuant to the terms of the certificate of designation creating the Series B Preferred Stock, upon a liquidation of our company, the holders of shares of the Series B Preferred Stock are entitled to receive a liquidation payment prior to the payment of any amount with respect to the shares of our common stock. The amount of this preferential liquidation payment is $5,000 per share of Series B Preferred Stock, plus the amount of any accrued but unpaid dividends on those shares. Dividends accrue on the shares of Series B Preferred Stock at a rate of 6% per annum increasing to a rate of 8% per annum on October 1, 2005.

We have granted to certain investors rights to participate in future financings, as well as exchange rights, which could be triggered upon future financings.

In connection with our October 2003 financing, we granted to the investors rights to participate in future financings and exchange rights, which could be triggered upon future financings if the price per share were less than that which the investors paid. The right to participate in future financings allows investors to purchase future securities issued by us for a period of time following the initial closing of their financing. The exchange rights allow the investors to exchange any securities held by them into future securities that we may issue at the liquidation preference of the exchanged security. Each of these factors may adversely affect our ability to raise additional funds from third parties on terms acceptable to us, or at all.

Common stock offered		4,848,485 shares
Warrants to purchase common stock offered		2,181,818 shares
Warrant exercise price		$2.00 per share of common stock
Warrant expiration date		December 21, 2009
Common stock outstanding after the offering		33,180,695 shares
Nasdaq National Market symbol		SATC

The table set forth above is based on 28,332,210 shares of common stock outstanding as of December 15, 2004 and assumes no exercise of outstanding options or warrants or the warrants offered hereby.

As of December 15, 2004, there were approximately 4,211,548 shares issuable upon exercise of options and warrants outstanding, of which approximately 3,628,690 shares were exercisable.

We estimate that the net proceeds to us from the sale of securities in this offering will be approximately $7,470,000, after deducting financial advisor fees and estimated offering expenses payable by us. As the warrants may be exercised only by "cashless exercise," we will not receive any additional proceeds upon exercise of the warrants.

We intend to use the net proceeds from the sale of securities offered by this prospectus supplement and the accompanying prospectus for general corporate purposes, including working capital for our business and the repayment of certain outstanding indebtedness. Pending these uses, we intend to invest the proceeds of this offering in short-term, interest-bearing instruments or other investment-grade securities. We will retain broad discretion in allocating the net proceeds of this offering.

For a description of our common stock, please read "Description of Common Stock" beginning on page 16 of the accompanying prospectus.

The material terms and provisions of the warrants being offered pursuant to this prospectus supplement and the accompanying prospectus are summarized below. This summary does not purport to be complete and is subject to, and qualified in its entirety by reference to, all the provisions of the warrants.

Exercisability. The warrants are exercisable, in whole or in part, at any time and from time to time during the period commencing on December 22, 2004 and ending on December 21, 2009. A holder may exercise a warrant by surrendering the warrant to us and only by "cashless exercise." "Cashless exercise" means that in lieu of paying the aggregate exercise price for the shares being purchased upon exercise of the warrant in cash, the holder will forfeit a number of shares underlying the warrant with a market value equal to such aggregate exercise price.

Exercise Price. The exercise price per share of common stock underlying the warrants is $2.00, subject to adjustment as described below.

Adjustments. The exercise price and the number of shares underlying the warrants are subject to appropriate adjustment in the event of stock splits, stock dividends on our common stock, stock combinations or similar events affecting our common stock. In addition, in the event we consummate any merger, consolidation, sale or other reorganization event in which our common stock is converted into or exchanged for securities, cash or other property, then following such event, the holders of the warrants will be entitled to receive upon exercise of the warrants the kind and amount of securities, cash or other property which the holders would have received had they exercised the warrants immediately prior to such reorganization event.

Fractional Shares. No fractional shares of common stock will be issued in connection with the exercise of a warrant. In lieu of fractional shares, we will pay the holder an amount in cash equal to the fractional amount multiplied by the market value of a share of common stock.

Transferability. A warrant may be transferred by a holder without our consent, upon surrender of the warrant to us, properly endorsed (by the holder executing an assignment in the form attached to the warrant) and upon payment of any necessary tax or other governmental charge imposed upon such transfer.

Ownership Cap and Exercise Restrictions. Under the terms of each warrant, at no time may a holder of a warrant exercise the warrant if the acquisition of the number of shares being purchased would result in the holder owning more than 4.999% of the common stock then outstanding.

Listing. The warrants will not be listed on any securities exchange or automated quotation system and we do not intend to arrange for any exchange or quotation system to list or quote the warrants.

The shares of common stock offered hereby are being offered for sale directly by us to several unrelated institutional investors. The price of the shares of common stock and warrants offered hereby was determined through negotiations between us and the purchasers.

Burnham Hill Partners, a division of Pali Capital, Inc. has been retained to act as our financial advisor in connection with potential capital raising activities, including interacting with potential investors regarding pricing and structuring of the shares and warrants to be issued in this offering. We have agreed to pay to the financial advisor a fee in the amount of $480,000 with respect to the sale of the shares and warrants offered hereby.

We expect to incur additional expenses in connection with this offering of approximately $50,000.

The validity of our securities offered in this prospectus supplement and the accompanying prospectus has been passed upon for us by Greenberg Traurig, LLP, Boston, Massachusetts.

This prospectus provides you with a general description of our securities that we may offer and sell from time to time. Each time we sell securities we will provide a prospectus supplement that will contain specific information about the terms of the securities offered and the specific manner in which we will offer the securities. The prospectus supplement will also contain information, where appropriate, about material United States federal income tax consequences relating to, and any listing on a securities exchange of the securities covered by the prospectus supplement. The prospectus supplement may add to, update or change the information in this prospectus. You should read this prospectus and any prospectus supplement carefully before you invest in our securities. This prospectus may not be used to sell securities unless accompanied by the applicable prospectus supplement.

Our common stock is traded on the Nasdaq National Market under the symbol "SATC." On June 15, 2004, the last reported sale price of our common stock on the Nasdaq National Market was $2.45.

See "Risk Factors" beginning on page 1 for a discussion of certain factors that you should consider before you invest in our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities, or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

		Page
Risk Factors		1
Special Statement Regarding Forward-Looking Information		11
About this Prospectus		11
About SatCon Technology Corporation		12
Where You Can Find More Information		12
Incorporation of Documents by Reference		12
Ratio of Earnings to Combined Fixed Charges and Preferred Dividends		13
How We Intend to Use the Proceeds		14
Description of the Securities		15
Description of Common Stock		16
Description of Preferred Stock		18
Description of Warrants		24
How We Plan to Sell the Securities		25
Experts		27
Legal Matters		27

You should rely only on the information contained or incorporated by reference in this prospectus or any applicable prospectus supplement. We have not authorized any other person to provide you with different information. If anyone provides you with different or inconsistent information, you should not rely on it. For further information, see the section of this prospectus entitled "Where You Can Find More Information." We are not making an offer to sell these securities in any jurisdiction where the offer or sale is not permitted.

You should not assume that the information appearing in this prospectus or any applicable prospectus supplement is accurate as of any date other than the date on the front cover of this prospectus or the applicable prospectus supplement, or that the information contained in any document incorporated by reference is accurate as of any date other than the date of the document incorporated by reference, regardless of the time of delivery of this prospectus or any prospectus supplement or any sale of a security. Our business, financial condition, results of operations and prospects may have changed since such dates.

Unless the context otherwise requires, all references to "we," "our," "us," "our company" or "the Company" in this prospectus refer collectively to SatCon Technology Corporation, a Delaware corporation, and its consolidated subsidiaries.

Before you invest in our securities, you should be aware that there are various risks, including those described below. You should consider carefully these risk factors together with all of the information included or incorporated by reference in this prospectus before you decide whether to invest in our securities. This section includes or refers to forward-looking statements; you should read the explanation of the qualifications and limitations on such forward-looking statements discussed elsewhere in this prospectus.

We have a history of operating losses, may not be able to achieve profitability and may require additional capital in order to sustain our businesses.

For each of the past eight fiscal years, we have experienced losses from operating our businesses. As of March 27, 2004, we had an accumulated deficit of approximately $125.3 million. During the six months ended March 27, 2004, we had a loss from operations of approximately $1.8 million. If we are unable to operate on a cash flow breakeven basis during 2004, we may need to raise additional capital in order to sustain our operations. There can be no assurance that we will be able to achieve such results or to raise such funds if they are required.

Our financial statements for our fiscal year ended September 30, 2003, which are included in our Annual Report on Form 10-K, contain an audit report from Grant Thornton LLP. The audit report contains a going concern qualification, which raises substantial doubt with respect to our ability to continue as a going concern. The receipt of a going concern qualification may create a concern among our current and future customers and vendors as to whether we will be able to fulfill our contractual obligations.

We could issue additional common stock, which might dilute the book value of our common stock.

We have authorized 50,000,000 shares of our common stock, of which 28,090,736 shares were issued and outstanding as of April 30, 2004. Our board of directors has the authority, without action or vote of our stockholders in most cases, to issue all or a part of any authorized but unissued shares. Such stock issuances may be made at a price that reflects a discount from the then-current trading price of our common stock. In addition, in order to raise capital that we may need at today's stock prices, we will need to issue securities that are convertible into or exercisable for a significant amount of our common stock. These issuances would dilute your percentage ownership interest, which will have the effect of reducing your influence on matters on which our stockholders vote, and might dilute the book value of our common stock. You may incur additional dilution of net tangible book value if holders of stock options, whether currently outstanding or subsequently granted, exercise their options or if warrant holders exercise their warrants to purchase shares of our common stock.

The sale or issuance of a large number of shares of our common stock could depress our stock price.

As of April 30, 2004, we have reserved 3,893,745 shares of common stock for issuance upon exercise of stock options and warrants, 2,057,680 shares for future issuances under our stock plans and 334,070 shares for future issuances as matching contributions under our 401(k) plan. As of April 30, 2004, holders of warrants and options to purchase an aggregate of 3,515,245 shares of our common stock may exercise those securities and transfer the underlying common stock at any time subject, in

some cases, to Rule 144. As of April 30, 2004, we have also reserved 850,000 shares of common stock for issuance upon conversion of the outstanding redeemable convertible Series B preferred stock, which can be converted at any time.

Financial investors may have interests different than you or SatCon, and may be able to impact corporate actions requiring stockholder approval because they own a significant amount of our common stock.

We have recently completed two significant financing transactions. In February 2003, we raised approximately $4,000,000 through the issuance of securities that were convertible into or exercisable for up to 50% or more of the number of shares of our common stock outstanding at that time. In October 2003, we raised an additional $7,675,000 through the issuance of 1,535 shares of our Series B Convertible Preferred Stock and warrants to purchase up to 1,228,000 shares of our common stock from 25 accredited investors. Prior to the October 2003 transaction, all of the convertible securities issued in connection with the February 2003 transaction were exercised or converted and as a result of the exercise and conversion of these securities we raised approximately $1.5 million.

In future financings, we may also issue securities that are convertible into or exercisable for a significant number of shares of our outstanding common stock. Financial investors such as those who participated in our 2003 financings may have short-term financial interests different from SatCon's long-term goals and the long-term goals of our management and other stockholders. In addition, based on their significant ownership of our outstanding common stock, financial investors may be able to impact corporate actions requiring stockholder approval.

We have not consistently complied with Nasdaq's Marketplace rules for continued listing, which exposes us to the risk of delisting from the Nasdaq National Market.

Our stock is listed on the Nasdaq National Market, which affords us an opportunity for relatively broad exposure to a wide spectrum of prospective investors. As a requirement of continued inclusion in the Nasdaq National Market, SatCon must comply with Nasdaq's Marketplace Rules, which require that we maintain a market value of $50 million or have total assets of $50 million and $50 million of total revenue and that our stock price stays above $1.00, among others. On August 14, 2003, SatCon received notice from Nasdaq that it was not in compliance with Marketplace Rules. Subsequently, SatCon was advised that it had achieved compliance, and as of April 30, 2004, SatCon is in compliance with the Nasdaq National Market Marketplace Rules for Continued Inclusion. However, if we fail to maintain compliance with these rules and our common stock is delisted from the Nasdaq National Market, there could be a number of negative implications, including reduced liquidity in our common stock as a result of the loss of market efficiencies associated with the Nasdaq National Market, the loss of federal preemption of state securities laws, the potential loss of confidence by suppliers, customers and employees, as well as the loss of analyst coverage and institutional investor interest, fewer business development opportunities and greater difficulty in obtaining financing.

We intend to continue to expand development of our power control products. We cannot assure you that potential customers will select SatCon's products to incorporate into their systems or that our customers' products will realize market acceptance, that they will meet the technical demands of their end users or that they will offer cost-effective advantages over existing products. Our marketing efforts to date involve development contracts with several customers, identification of specific market segments for power and energy management systems and the continuation of marketing efforts of recently acquired businesses. We cannot know if our commercial marketing efforts will be successful in the future. Furthermore, we cannot assure you that our products, in their current form, will be suitable for

specific commercial applications or that further design modifications, beyond anticipated changes to accommodate different markets, will not be necessary. Additionally, we may not be able to develop competitive products, our products may not receive market acceptance, and we may not be able to profitably compete in this market even if market acceptance is achieved. If our products do not gain market acceptance or commercial viability, we will not achieve our anticipated levels of profitability and growth.

If we are unable to maintain our technological expertise in design and manufacturing processes, we will not be able to successfully compete.

We believe that our future success will depend upon our ability to develop and provide products that meet the changing needs of our customers. This requires that we successfully anticipate and respond to technological changes in design and manufacturing processes in a cost-effective and timely manner. As a result, we continually evaluate the advantages and feasibility of new product design and manufacturing processes. We cannot, however, assure you that our process development efforts will be successful. The introduction of new products embodying new technologies and the emergence of shifting customer demands or changing industry standards could render our existing products obsolete and unmarketable which would have a significant impact on our ability to generate revenue. Our future success will depend upon our ability to continue to develop and introduce a variety of new products and product enhancements to address the increasingly sophisticated needs of our customers. This will require us to continue to make substantial product development investments. We may experience delays in releasing new products and product enhancements in the future. Material delays in introducing new products or product enhancements may cause customers to forego purchases of our products and purchase those of our competitors.

Our ability to develop and market our products is heavily dependent upon maintaining our U.S. government contract revenue and research grants. Most of our U.S. government contracts are funded incrementally on a year-to-year basis. Approximately 50% of our revenue during fiscal year 2003 was derived from government contracts and subcontracts with the U.S. government's prime contractors. Any change in our relationship with the U.S. government or its agencies whether as a result of market, economic, or competitive pressures, including any decision by the U.S. government to alter its commitment to our research and development efforts, could harm our business and financial condition by depriving us of the resources necessary to develop our products. In addition there can be no assurance that once a government contract is completed that it will lead to follow-on contracts for additional research and development, prototype build and test, or production. Furthermore, contracts with the U.S. government may be terminated or suspended by the U.S. government at any time, with or without cause. There can be no assurance that our U.S. government contracts will not be terminated or suspended in the future, or that contract suspensions or terminations will not result in unreimbursable expenses or charges or other adverse effects on us.

inquiries or audits of our contracts could have a material adverse impact on our financial condition or results of operations.

In the event that any of our government contracts are terminated for cause, it could significantly affect our ability to obtain future government contracts, which could seriously harm our ability to develop our technologies and products.

A significant portion of our revenue is derived from contracts with the U.S. government and its agencies or from subcontracts with the U.S. government's prime contractors, and a slowdown in government spending may adversely affect our ability to obtain anticipated revenues.

Changes in government policies, priorities or funding levels through agency or program budget reductions by the U.S. Congress or executive agencies or the imposition of budgetary constraints could significantly impair our ability to achieve this level of revenue going forward. Any reductions or slowdowns in government spending could also severely inhibit our ability to successfully complete the development and commercialization of our products. Changes in funding levels could cause the government to cancel existing contracts or eliminate follow-on phases in the future.

The U.S. government has certain rights relating to our intellectual property.

Many of our patents are the result of retaining ownership of inventions made under U.S. government-funded research and development programs. With respect to any invention made with government assistance, the government has a nonexclusive, nontransferable, irrevocable, paid-up license to use the technology or have the technology employed for or on behalf of the U.S. government throughout the world. Under certain conditions, the U.S. government also has "march-in rights." These rights enable the U.S. government to require us to grant a nonexclusive, partially exclusive, or exclusive license in any field of use to responsible applicants, upon terms that are reasonable under the circumstances. If we refuse, the government can grant the license itself, provided that it determines that such action is necessary because we have not achieved practical application of the invention, or to alleviate health or safety needs, or to meet requirements for public use specified by federal regulations, or because products using such inventions are not being produced substantially in the United States. The exercise of these rights by the government could create potential competitors for us if we later determine to further develop the technologies and utilize the inventions in which the government has exercised these rights.

Our business could be adversely affected if we are unable to protect our patents and proprietary technology.

As of April 30, 2004, we held 72 U.S. patents and had 3 patent applications pending with the U.S. Patent and Trademark Office. We have also obtained corresponding patents in the rest of North America, Europe, and Asia for many of these patents. The expiration date of our patents range from 2009 to 2021, with the majority expiring after 2015. As a qualifying small business from our inception to date, we have retained commercial ownership rights to proprietary technology developed under various U.S. government contracts and grants.

technologies that are substantially equivalent or superior to ours. No assurance can be given as to the issuance of additional patents or, if so issued, as to their scope. Patents granted may not provide meaningful protection from competitors. Even if a competitor's products were to infringe patents owned by us, it would be costly for us to pursue our rights in an enforcement action and there can be no assurance that we would be successful in enforcing our intellectual property rights. Because we intend to enforce our patents, trademarks and copyrights and protect our trade secrets, we may be involved from time to time in litigation to determine the enforceability, scope and validity of these rights. This litigation could result in substantial costs to us and divert resources from operational goals. In addition, effective patent, trademark, service mark, copyright and trade secret protection may not be available in every country where we operate or sell our products.

We may not be able to maintain confidentiality of our proprietary knowledge.

In addition to our patent rights, we also rely on treatment of our technology as trade secrets and upon confidentiality agreements, which all of our employees are required to sign, assigning to us all patent rights and technical or other information developed by the employees during their employment with us. We also rely, in part, on contractual provisions to protect our trade secrets and proprietary knowledge. Our employees have also agreed not to disclose any trade secrets or confidential information without our prior written consent. These agreements may be breached, and we may not have adequate remedies for any breach. Our trade secrets may also be known without breach of these agreements or may be independently developed by competitors. Our inability to maintain the proprietary nature of our technology and information could harm our business, results of operations and financial condition by adversely affecting our ability to compete in our markets.

Others may assert that our technology infringes their intellectual property rights.

We believe that we do not infringe the proprietary rights of others and, to date, no third parties have asserted an infringement claim against us, but we may be subject to infringement claims in the future. The defense of any claims of infringement made against us by third parties could involve significant legal costs and require our management to divert time from our business operations. If we are unsuccessful in defending any claims of infringement, we may be forced to obtain licenses or to pay royalties to continue to use our technology. We may not be able to obtain any necessary licenses on commercially reasonable terms or at all. If we fail to obtain necessary licenses or other rights, or if these licenses are costly, our operating results may suffer either from reductions in revenues through our inability to serve customers or from increases in costs to license third-party technologies.

Loss of any of our key personnel, and particularly our Chief Executive Officer, could hurt our business because of their experience, contacts and technological expertise.

The loss of the services of one or more of our key employees or an inability to attract, train and retain qualified and skilled employees, specifically engineering and sales personnel, could result in the loss of customers or otherwise inhibit our ability to operate and grow our business successfully. In addition, our ability to successfully integrate acquired facilities or businesses depends, in part, on our ability to retain and motivate key management and employees hired by us in connection with these acquisitions. We have been particularly dependent upon the services of David B. Eisenhaure, our president, chief executive officer, chairman of the board and founder, as a result of his business and academic relationships, understanding of government contracts and technical expertise. The loss of Mr. Eisenhaure's services could have a material adverse effect on our business.

In the past, we faced limited competition in providing research services, prototype development and custom and limited quantity manufacturing. We expect competition to intensify greatly as

commercial applications increase for our products under development. Many of our competitors and potential competitors are well established and have substantially greater financial, research and development, technical, manufacturing and marketing resources than we do. Some of our competitors and potential competitors are much larger than we are. If these larger competitors decide to focus on the development of distributed power and power quality products, they have the manufacturing, marketing and sales capabilities to complete research, development and commercialization of these products more quickly and effectively than we can. There can also be no assurance that current and future competitors will not develop new or enhanced technologies perceived to be superior to those sold or developed by us. There can be no assurance that we will be successful in this competitive environment.

Price increases of materials or components used by us could adversely affect the volume of our sales.

We use materials and components obtained from third-party suppliers to manufacture many of our products. If prices of materials and components that we use were to increase, we may not be able to afford them or to pass these costs on to our customers. Since some of our vendors are single sourced, our ability to consider lower priced options are limited in the short run. In addition, if we were required to raise the price of our products as a result of increases in the price of materials or components that we use, demand for our products may decrease which would reduce our sales.

We are dependent on third-party suppliers for the supply of key components for our products.

We use third-party suppliers for components in many of our systems. From time to time, shipments can be delayed because of industry-wide or other shortages of necessary materials and components from third-party suppliers. A supplier's failure to supply components in a timely manner, or to supply components that meet our quality, quantity or cost requirements, or our inability to obtain substitute sources of these components on a timely basis or on terms acceptable to us, could impair our ability to manufacture our products. If alternative sources are identified, we may not be able to successfully integrate those components into our system without incurring additional cost and risk. In addition, to the extent the processes that our suppliers use to manufacture components are proprietary, we may be unable to obtain comparable components from alternative suppliers.

Long-term contracts are not typical in our business, and reductions, cancellations or delays in customer orders would adversely affect our operating results.

Other than certain contracts in our Applied Technology Division, we typically do not obtain long-term purchase orders or commitments from our customers. Instead, we work closely with our customers to develop accurate non-binding forecasts of the future volume and timing of orders to effectively allocate and manage our resources. Customers may cancel their orders, change production quantities from forecasted volumes or delay production for a number of reasons beyond our control. Significant or numerous cancellations, reductions or delays in orders by our customers would reduce or delay our net sales.

If we experience a period of significant growth or expansion, it could place a substantial strain on our resources.

If we are successful in obtaining rapid market penetration of our power control products, we may be required to deliver large volumes of technically complex products or components to our customers on a timely basis at reasonable costs to us. We have limited experience in ramping up our manufacturing capabilities to meet large-scale production requirements and delivering large volumes of our power control products. If we were to commit to deliver large volumes of our power control products, we cannot assure you that our efforts will be successful, that we will be able to satisfy large-

scale commercial production on a timely and cost-effective basis or that such growth will not strain our operational and technical resources.

Our business exposes us to potential product liability claims, which are inherent in the manufacturing, marketing and sale of our products, and we may face substantial liability for damages resulting from the faulty design or manufacture of products or improper use of products by end users. We currently maintain a low level of product liability insurance, and there can be no assurance that this insurance will provide sufficient coverage in the event of a claim. Also, we cannot predict whether we will be able to maintain such coverage on acceptable terms, if at all, or that a product liability claim would not harm our business or financial condition. In addition, negative publicity in connection with the faulty design or manufacture of our products would adversely affect our ability to market and sell our products.

We are subject to a variety of environmental laws that expose us to potential financial liability.

Our operations are regulated under a number of federal, state and foreign environmental and safety laws and regulations that govern, among other things, the discharge or release of hazardous materials into the air and water as well as the handling, storage and disposal of these materials. These laws and regulations include the Clean Air Act, the Clean Water Act, the Resource, Conservation and Recovery Act, and the Comprehensive Environmental Response, Compensation and Liability Act, as well as analogous state and foreign laws. Because we use hazardous materials in our manufacturing processes, we are required to comply with these environmental laws. In addition, because we generate hazardous wastes, we, along with any other person who arranges for the disposal of our wastes, may be subject to potential financial exposure for costs associated with an investigation and any remediation of sites at which we have arranged for the disposal of hazardous wastes if those sites become contaminated and even if we fully comply with applicable environmental laws. In the event of a violation of environmental laws, we could be held jointly and severably liable for damages and for the costs of remedial actions. Environmental laws could also become more stringent over time, imposing greater compliance costs and increasing risks and penalties associated with any violation, although, to-date, we have not been cited for any improper discharge or release of hazardous materials.

Businesses and consumers might not adopt alternative distributed power solutions as a means for obtaining their electricity and power needs.

On-site distributed power generation solutions, such as fuel cell, photovoltaic and wind turbine systems, which utilize our products, provide an alternative means for obtaining electricity and are relatively new methods of obtaining electricity and other forms of power that businesses may not adopt at levels sufficient to grow this part of our business. Traditional electricity distribution is based on the regulated industry model whereby businesses and consumers obtain their electricity from a government regulated utility. For alternative methods of distributed power to succeed, businesses and consumers must adopt new purchasing practices and must be willing to rely less upon traditional means of purchasing electricity. We cannot assure you that businesses and consumers will choose to utilize this on-site distributed power market at levels sufficient to sustain our business. The development of a mass market for our products may be impacted by many factors which are out of our control, including:

If a mass market fails to develop or develops more slowly than we anticipate, we may be unable to recover the losses we will have incurred to develop these products.

The distributed power generation industry may become subject to future government regulation, which may impact our ability to market our products.

We do not believe that our products will be subject to existing federal and state regulations governing traditional electric utilities and other regulated entities. We do believe that our products will be subject to oversight and regulation at the federal, state or local level in accordance with state and local ordinances relating to building codes, safety, pipeline connections and related matters. This regulation may depend, in part, upon whether an on-site distributed power system is placed outside or inside a home. At this time, we do not know which jurisdictions, if any, will impose regulations upon our products. We also do not know the extent to which any existing or new regulations may impact our ability to sell and service our products. Once our customers' products reach the commercialization stage and they begin distributing systems to their target markets, federal, state or local government entities may seek to impose additional regulations. Any new government regulation of our products, whether at the federal, state or local level, including any regulations relating to installation and servicing of our products, may increase our costs and the price of our products and may have a negative impact on our revenue and profitability.

Our quarterly operating results are subject to fluctuations, and if we fail to meet the expectations of securities analysts or investors, our share price may decrease significantly.

Our annual and quarterly results may vary significantly depending on various factors, many of which are beyond our control.

Because our operating expenses are based on anticipated revenue levels, our sales cycle for development work is relatively long and a high percentage of our expenses are fixed for the short term, a small variation in the timing of recognition of revenue can cause significant variations in operating results from quarter to quarter. If our earnings do not meet the expectations of securities analysts or investors, the price of our stock could decline.

As of April 30, 2004, our executive officers and directors, and their affiliates, beneficially owned approximately 3,948,804 of our outstanding shares of common stock, representing approximately 13.6% of our outstanding common stock, a majority of which was beneficially owned by Mr. Eisenhaure, our president, chief executive officer, chairman of the board and founder. Specifically, as of such date, Mr. Eisenhaure beneficially owned 3,134,262 shares of our common stock, representing 11.0% of our outstanding common stock. If all of these stockholders were to vote together as a group, they would have the ability to exert significant influence over our board of directors and its policies. As a practical matter, Mr. Eisenhaure has significant influence over the election of our directors and determining the outcome of corporate actions requiring stockholder approval, including votes concerning director elections, bylaw amendments and possible mergers, corporate control contests and other significant corporate transactions, irrespective of how some of our other stockholders may vote. Accordingly, such concentration of ownership may have the effect of delaying, deterring or preventing a change in control, impeding a merger, consolidation, takeover or other business combination involving us, or discouraging a potential acquirer from making a tender offer or otherwise attempting to obtain control of us, which in turn could have an adverse effect on the market price of our common stock.

Provisions in our charter documents and Delaware law may delay, deter or prevent the acquisition of SatCon, which could decrease the value of your shares.

Some provisions of our certificate of incorporation and bylaws may delay, deter or prevent a change in control of SatCon or a change in our management that you as a stockholder may consider favorable. These provisions include:

We are subject to stringent export laws and risks inherent in international operations.

We market and sell our products and services both inside and outside the United States. We are currently selling our products and services throughout North America and in certain countries in South America, Asia, Canada and Europe. Certain of our products are subject to the International Traffic in Arms Regulations (ITAR) 22 U.S.C 2778, which restricts the export of information and material that may be used for military or intelligence applications by a foreign person. Additionally, certain products of ours are subject to export regulations administered by the Department of Commerce, Bureau of Industry Security, which require that we obtain an export license before we can export products or technology. Failure to comply with these laws could result in sanctions by the government, including substantial monetary penalties, denial of export privileges and debarment from government contracts.

Revenue from sales to our international customers for our fiscal years ended September 30, 2003 and 2002 were $3.3 million and $7.2 million, respectively. Our success depends, in part, on our ability to expand our market for our products and services to foreign customers and our ability to manufacture products that meet foreign regulatory and commercial requirements. We have limited experience developing and manufacturing our products to comply with the commercial and legal requirements of international markets. We face numerous challenges in penetrating international markets, including unforeseen changes in regulatory requirements, export restrictions, fluctuations in currency exchange rates, longer accounts receivable cycles, difficulties in managing international operations, and the challenges of complying with a wide variety of foreign laws.

You are unlikely to be able to exercise effective remedies against Arthur Andersen LLP, our former independent public accountants.

Arthur Andersen guilty of these federal obstruction of justice charges. In light of the jury verdict and the underlying events, Arthur Andersen subsequently substantially discontinued operations and dismissed essentially its entire workforce. You are therefore unlikely to be able to exercise effective remedies or collect judgments against Arthur Andersen. In addition, Arthur Andersen has not consented to the inclusion of its report in this prospectus, and the requirement to file its consent has been dispensed with in reliance on Rule 437a promulgated under the Securities Act of 1933. Because Arthur Andersen has not consented to the inclusion of its report in this prospectus, you will not be able to recover against Arthur Andersen under Section 11 of the Securities Act for any untrue statement of a material fact contained in the financial statements audited by Arthur Andersen or any omissions to state a material fact required to be stated in those financial statements.

To the extent our customers do not advance us sufficient funds to finance our expenses during the execution phase of our contracts, we are exposed to the risk that they will be unable to accept delivery or that they will be unable to make payment at the time of delivery. Occasionally, we accept the risk of dealing with thinly financed entities. We attempt to mitigate this risk by seeking to negotiate more timely progress payments and utilizing other risk management procedures.

Our agreement with Silicon Valley Bank subjects us to various restrictions, which may limit our ability to pursue business opportunities.

These restrictions may also limit our ability to pursue business opportunities or strategies that we would otherwise consider to be in our best interests.

Our agreement with Silicon Valley Bank contains certain covenants that we may fail to satisfy which, if not satisfied, could result in the acceleration of the amounts due under such agreement and the limitation of our ability to borrow additional funds in the future.

As of April 30, 2004, we had no borrowings under our financing agreement with The Silicon Valley Bank. This agreement subjects us to various financial and other covenants with which we must comply on an ongoing or periodic basis. The financial covenant requires us to maintain a minimum level of tangible net worth, as defined, which varies from month to month. If we violate this or any other covenant, there may be a material adverse effect on us. Most notably, our outstanding debt under this agreement could become immediately due and payable, the bank could proceed against any collateral securing such indebtedness and our ability to borrow additional funds in the future may be limited.

The holders of our Series B Preferred Stock are entitled to receive liquidation payments in preference to the holders of our common stock.

As of April 30, 2004, 425 shares of our Series B Preferred Stock were outstanding. Pursuant to the terms of the certificate of designation creating the Series B Preferred Stock, upon a liquidation of our company, the holders of shares of the Series B Preferred Stock are entitled to receive a liquidation

payment prior to the payment of any amount with respect to the shares of our common stock. The amount of this preferential liquidation payment is $5,000 per share of Series B Preferred Stock, plus the amount of any accrued but unpaid dividends on those shares. Dividends accrue on the shares of Series B Preferred Stock at a rate of 6% per annum increasing to a rate of 8% per annum on October 1, 2005.

We have granted to certain investors rights of first refusal and exchange rights which would be triggered upon future financings.

In connection with our October 2003 financing, we granted rights of first refusal and exchange rights which would generally be triggered upon future financings we may seek to consummate. The right of first refusal allows investors to purchase future securities issued by us for a period of time following the initial closing of their financing. The exchange rights allow the investors to exchange any securities held by them into future securities that we may issue at the liquidation preference of the exchanged security. Each of these factors may adversely affect our ability to raise additional funds from third parties on terms acceptable to us, or at all.

This prospectus includes and incorporates forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. All statements, other than statements of historical facts, included or incorporated in this prospectus regarding our strategy, future operations, financial position, future revenues, projected costs, prospects, plans and objectives of management are forward-looking statements. The words "anticipates," "believes," "estimates," "expects," "intends," "may," "plans," "projects," "will," "would" and similar expressions are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. We cannot guarantee that we actually will achieve the plans, intentions or expectations disclosed in our forward-looking statements and you should not place undue reliance on our forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements we make. We have included important factors in the cautionary statements included or incorporated in this prospectus, particularly under the heading "Risk Factors," that we believe could cause actual results or events to differ materially from the forward-looking statements that we make. Our forward-looking statements do not reflect the potential impact of any future acquisitions, mergers, dispositions, joint ventures or investments we may make. We do not assume any obligation to update any forward-looking statements.

This prospectus is part of a registration statement filed with the SEC utilizing a shelf registration process. Under this shelf registration process, we may sell any combination of the securities described in this prospectus in one or more offerings up to a total dollar amount of $25,000,000.

This prospectus provides you with a general description of the securities we may offer. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that specific offering. The prospectus supplement may also add to, update or change information contained in this prospectus. You should read both this prospectus and any prospectus supplement together with the additional information described under the heading "Where You Can Find More Information."

We design, develop and manufacture efficient high power electronics and standard and custom machines that convert, store and manage electricity for customers that require reliable, "always-on," electric power. We also design, develop and manufacture highly reliable electronics and controls for government and military applications. Our specialty motors are typically designed and manufactured for customers that purchase small efficient motors requiring high power relative to the size of the motor.

Our common stock is quoted on the Nasdaq National Market under the symbol "SATC." Our executive offices are located at 161 First Street, Cambridge, Massachusetts 02142 and our telephone number is (617) 661-0540.

We are subject to the information requirements of the Securities Exchange Act of 1934, as amended, or Exchange Act, and in accordance with the Exchange Act, file annual, quarterly and special reports, proxy statements and other information with the SEC. You may read and copy any document we file at the SEC's Public Reference Room at 450 Fifth Street, N.W., Washington, D.C. 20549. You may call the SEC at 1-800-SEC-0330 for further information on the operation of the Public Reference Room. Our SEC filings are also available to the public from the SEC's website at http://www.sec.gov.

We have the authority to designate and issue more than one class or series of stock having various preferences, conversion and other rights, voting powers, restrictions, limitations as to dividends, qualifications, and terms and conditions of redemption. See "Description of Preferred Stock" and "Description of Common Stock." We will furnish a full statement of the relative rights and preferences of each class or series of our stock that has been so designated and any restrictions on the ownership or transfer of our stock to any stockholder upon request and without charge. Written requests for such copies should be directed to SatCon Technology Corporation, 161 First Street, Cambridge, Massachusetts 02142, Attention: Investor Relations Department. Our telephone number is (617) 661-0540. Our website is located at http:/www.satcon.com. Information contained on our website is not incorporated by reference into this prospectus and, therefore, is not part of this prospectus or any accompanying prospectus supplement.

This prospectus is part of a registration statement that we filed with the SEC. The registration statement contains more information than this prospectus regarding us and our securities, including certain exhibits and schedules. You can obtain a copy of the registration statement from the SEC at the address listed above or from the SEC's website.

The SEC allows us to incorporate by reference the information that we file with the SEC in other documents. Incorporation by reference means that we can disclose important information to you by referring you to other documents that are legally considered to be part of this prospectus and later information that we file with the SEC will automatically update and supersede the information in this prospectus, any supplement and the documents listed below. We incorporate by reference the specific documents listed below and any future filings made with the SEC under Section 13(a), 13(c), 14, or 15(d) of the Exchange Act, until we sell all of the securities registered hereunder or otherwise terminate the offering of the securities:

Upon request, we will provide, without charge, to any person to whom a copy of this prospectus is delivered, a copy of any or all of the documents that have been incorporated by reference in this prospectus. All requests should be made to: SatCon Technology Corporation, 161 First Street, Cambridge, Massachusetts 02142, Attention: Investor Relations Department. Telephone requests may be directed to the Investor Relations Department at (617) 661-0540.

You should rely only on the information contained in this prospectus, including information incorporated by reference as described above, or any prospectus supplement that we have specifically referred you to. We have not authorized anyone else to provide you with different information. You should not assume that the information in this prospectus or any prospectus supplement is accurate as of any date other than the date on the front of those documents or that any document incorporated by reference is accurate as of any date other than its filing date. You should not consider this prospectus to be an offer or solicitation relating to the securities in any jurisdiction in which such an offer or solicitation relating to the securities is not authorized. Furthermore, you should not consider this prospectus to be an offer or solicitation relating to the securities if the person making the offer or solicitation is not qualified to do so, or if it is unlawful for you to receive such an offer or solicitation.

We have not recorded earnings for any of our last five fiscal years or for the six months ended March 27, 2004, and, therefore, are unable to cover combined fixed charges and preferred dividends. Loss consists of loss before provision for income taxes and cumulative effects of accounting changes plus fixed charges. Fixed charges consist of interest expense and a portion of rental expense that we believe to be representative of interest. The ratio of earnings to combined fixed charges and preferred dividends was computed by dividing earnings by combined fixed charges and preferred dividends. The following table discloses our dollar coverage deficiency.

			Years Ended September 30,
	Six Months Ended March 27, 2004
	2003		2002		2001		2000		1999
Earnings (in thousands)	$	(1,540	)	$	(26,765	)	$	(19,736	)	$	(16,168	)	$	(8,391	)	$	(9,381	)
Combined Fixed Charges and Preferred Dividends (in thousands)	$	7,024		$	4,716		$	1,025		$	923		$	3,757		$	671
Ratio of Earnings to Combined Fixed Charges and Preferred Dividends		(0.22	)		(5.68	)		(19.25	)		(17.52	)		(2.23	)		(13.98	)
Coverage deficiency to attain a ratio of 1:1 (in thousands)	$	8,564		$	31,481		$	20,761		$	17,091		$	12,148		$	10,052

We currently intend to use the net proceeds from the sale of any securities under this prospectus for general corporate purposes, which may include:

Pending such use, we may temporarily invest the net proceeds. The precise amounts and timing of the application of proceeds will depend upon our funding requirements and the availability of other funds. Except as mentioned in any prospectus supplement, specific allocations of the proceeds to such purposes will not have been made at the date of that prospectus supplement.

Based upon our historical and anticipated future growth and our financial needs, we may engage in additional financings of a character and amount that we determine as the need arises.

We may offer, from time to time, in one or more offerings, up to $25 million of the following securities:

The aggregate initial offering price of the offered securities that we may issue will not exceed $25 million.

This prospectus contains a summary of the general terms of the various securities that we may offer. The prospectus supplement relating to any particular securities offered will describe the specific terms of the securities, which may be in addition to or different from the general terms summarized in this prospectus. Because the summary in this prospectus and in any prospectus supplement does not contain all of the information that you may find useful, you should read the documents relating to the securities that are described in this prospectus or in any applicable prospectus supplement. Please read "Where You Can Find More Information" to find out how you can obtain a copy of those documents.

The applicable prospectus supplement will also contain the terms of a given offering, the initial offering price and our net proceeds. Where applicable, a prospectus supplement will also describe any material United States federal income tax consequences relating to the securities offered and indicate whether the securities offered are or will be quoted or listed on any quotation system or securities exchange.

The following is a description of the material terms and provisions of our common stock. It may not contain all the information that is important to you. You can access complete information by referring to our certificate of incorporation and bylaws.

Under our certificate of incorporation, we have authority to issue 50,000,000 shares of common stock, par value $0.01 per share. As of June 2, 2004, there were 28,129,479 shares of common stock issued and outstanding. All shares of common stock will, when issued, be duly authorized, fully paid and nonassessable. Accordingly, the full price for the outstanding shares of common stock will have been paid at issuance and any holder of our common stock will not be later required to pay us any additional money for such common stock.

Subject to the prior rights of any series of preferred stock which may from time to time be outstanding, the holders of our common stock are entitled to receive such dividends, if any, as may be declared from time to time by our board of directors out of legally available funds. In the event we are liquidated, dissolved or our affairs are wound up, after we pay or make adequate provision for all of our known debts and liabilities, each holder of common stock will receive dividends pro rata out of assets that we can legally use to pay distributions, subject to any rights that are granted to the holders of any class or series of preferred stock.

Holders of common stock will have the exclusive power to vote on all matters presented to our stockholders, including the election of directors, except as otherwise provided by Delaware law or as provided with respect to any other class or series of stock. Holders of common stock are entitled to one vote per share. There is no cumulative voting in the election of our directors, which means that, subject to any rights to elect directors that are granted to the holders of any class or series of preferred stock, a plurality of the votes cast at a meeting of stockholders at which a quorum is present is sufficient to elect a director.

Subject to the preferential rights of any other class or series of stock, all shares of common stock have equal dividend, distribution, liquidation and other rights, and have no preference, appraisal or exchange rights, except for any appraisal rights provided by Delaware law. Furthermore, holders of common stock have no conversion, sinking fund or redemption rights, or preemptive rights to subscribe for any of our securities.

The transfer agent and registrar for our common stock is American Stock Transfer and Trust Company. Its address is 59 Maiden Lane, Plaza Level, New York, NY 10038.

Our common stock is quoted on the Nasdaq National Market under the symbol "SATC."

The following is a description of the material terms and provisions of our preferred stock. It may not contain all the information that is important to you. You can access complete information by referring to our certificate of incorporation and bylaws and to any applicable amendment to the certificate of incorporation designating terms of a series of preferred stock.

Under our certificate of incorporation, we have authority to issue 1,000,000 shares of preferred stock, par value $.01 per share.

As of April 30, 2004, 425 shares of our Series B Preferred Stock were outstanding. The shares of Series B Preferred Stock bear a cumulative dividend at a rate of 6% per annum of the $5,000 per share liquidation preference, increasing to a rate of 8% per annum on October 1, 2005. Dividends are payable semi-annually and, except in certain limited circumstances, may be paid by us, at our option, either through the issuance of shares of common stock or in cash. In the event of a liquidation of our company, the holders of shares of the Series B Preferred Stock are entitled to receive a liquidation payment prior to the payment of any amount with respect to the shares of our common stock. The amount of this preferential liquidation payment is $5,000 per share of Series B Preferred Stock, plus the amount of any accrued but unpaid dividends on those shares. Each outstanding share of Series B Preferred Stock is convertible into a number of shares of common stock equal to $5,000 divided by the conversion price of the Series B Preferred Stock, which is currently $2.50, but may be adjusted if certain events occur, including the issuance of shares of common stock at a price less than the conversion price. The holders of Series B Preferred Stock are entitled to redeem their shares of Series B Preferred Stock immediately prior to the consolidation, merger or business combination of SatCon with another entity, the sale or transfer of more than 50% of SatCon's assets or the closing of a purchase, tender or exchange offer made to the holders of more than 50% of the outstanding common stock. In such an event, the redemption price per share will equal $6,250 plus any accrued but unpaid dividends and liquidated damages. We may pay the redemption price in either cash or shares of common stock.

We did not have any other shares of preferred stock outstanding as of the date of this prospectus. Shares of preferred stock may be issued from time to time, in one or more series, as authorized by our board of directors. Prior to the issuance of shares of each series, the board of directors is required by the Delaware General Corporation Law and our certificate of incorporation to fix, for each series, the designations, powers and preferences and the relative, participating, optional or other special rights of the shares of each series and any qualifications, limitations and restrictions thereof, as are permitted by Delaware law. Our board of directors could authorize the issuance of shares of preferred stock with terms and conditions that could have the effect of discouraging a takeover or other transactions that holders of common stock might believe to be in their best interests or in which holders of some, or a majority, of the shares of common stock might receive a premium for their shares over the then market price of such shares of common stock. When issued, the preferred stock will be fully paid and nonassessable and will have no preemptive rights.

You should refer to the applicable prospectus supplement relating to the preferred stock offered thereby for specific terms, including, where applicable, the following terms:

Unless otherwise specified in the prospectus supplement, the preferred stock will, with respect to dividend rights and rights upon our liquidation, dissolution or winding up our affairs, rank:

Holders of the preferred stock of each series will be entitled to receive cash dividends, when, as and if declared by our board of directors. We will pay dividends out of assets which are legally available for payment of dividends. We will specify the rate(s) of dividends and the dates that we will pay dividends in the applicable prospectus supplement. Dividends will be payable to holders of record as

they appear on our stock transfer books on such record dates as shall be fixed by our board of directors.

Dividends on any series of the preferred stock may be cumulative or non-cumulative, as provided in the applicable prospectus supplement. Dividends, if cumulative, will be cumulative from and after the date set forth in the applicable prospectus supplement. If our board of directors fails to declare a dividend payable on a dividend payment date on any series of the preferred stock for which dividends are non-cumulative, then the holders of such series of the preferred stock will have no right to receive a dividend in respect of the dividend period ending on that dividend payment date. Accordingly, we will have no obligation to pay the dividend accrued for that period, whether or not dividends on that series are declared payable on any future dividend payment date.

If preferred stock of any series is outstanding, we will not declare, pay or set aside funds to pay dividends on any other series of our capital stock ranking, as to dividends, on parity with or junior to the preferred stock of such series for any period unless:

We must declare all dividends pro rata on all series of preferred stock that rank on parity with the series of preferred stock upon which we paid dividends if we did not pay or set aside funds to pay dividends on the series of preferred stock in full. We must declare dividends pro rata to ensure that the amount of dividends declared per share of preferred stock bear in all cases the same ratio that accrued dividends per share of preferred stock bears to each other. We will not accumulate unpaid dividends for prior dividend periods with respect to accrued dividends on preferred stock that do not have cumulative dividends. No interest, or sum of money in lieu of interest, shall be payable in respect of any dividend payment or payments on preferred stock of such series which may be in arrears.

we will not: (1) declare or pay or set aside funds to pay dividends; (2) declare or make any other distribution upon the common stock or any other shares of our stock ranking junior to or on parity with the preferred stock of such series as to dividends or upon liquidation; (3) redeem, purchase or otherwise acquire for any consideration any common stock, or any other shares of our stock ranking junior to or on parity with the preferred stock of such series as to dividends; nor (4) pay any monies to or make any monies available for a sinking fund to redeem of any such shares, except by conversion into or exchange for other of our shares of our capital stock ranking junior to the preferred stock of such series as to dividends or liquidation. Notwithstanding the preceding sentence, we may declare or set aside dividends in common stock or other shares of capital stock ranking junior to the preferred stock of such series as to dividends and upon liquidation.

Any dividend payment we make on a series of preferred stock shall first be credited against the earliest accrued but unpaid dividend due with respect to shares of such series which remain payable.

If so provided in the applicable prospectus supplement, the preferred stock will be subject to mandatory redemption or redemption at our option, as a whole or in part, in each case upon the terms, at the times and at the redemption prices set forth in such prospectus supplement.

The prospectus supplement relating to a series of preferred stock that is subject to mandatory redemption will specify the number of shares of preferred stock that shall be redeemed by us in each year commencing after a date to be specified, at a redemption price per share to be specified, together with an amount equal to all accrued and unpaid dividends thereon to the date of redemption. Unless the shares have a cumulative dividend, such accrued dividends will not include any accumulation in respect of unpaid dividends for prior dividend periods. We may pay the redemption price in cash or other property, as specified in the applicable prospectus supplement. If the redemption price for preferred stock of any series is payable only from the net proceeds of the issuance of shares of our capital stock, the terms of such preferred stock may provide that, if no such shares of our capital stock shall have been issued or to the extent the net proceeds from any issuance are insufficient to pay in full the aggregate redemption price then due, such preferred stock shall automatically and mandatorily be converted into the applicable shares of our capital stock pursuant to conversion provisions specified in the applicable prospectus supplement.

Notwithstanding the foregoing, we will not redeem any preferred stock of a series unless:

However, in no case will we redeem any preferred stock of a series unless we redeem all outstanding preferred stock of such series simultaneously.

However, at any time we may purchase or acquire preferred stock of that series (1) pursuant to a purchase or exchange offer made on the same terms to holders of all outstanding preferred stock of such series or (2) by conversion into or exchange for shares of our capital stock ranking junior to the preferred stock of such series as to dividends and upon liquidation.

If fewer than all of the outstanding shares of preferred stock of any series are to be redeemed, we will determine the number of shares that may be redeemed pro rata from the holders of record of such shares in proportion to the number of such shares held or for which redemption is requested by such

holder or by any other equitable manner that we determine. Such determination will reflect adjustments to avoid redemption of fractional shares.

We will mail notice of redemption at least 30 days but not more than 60 days before the redemption date to each holder of record of preferred stock to be redeemed at the address shown on our stock transfer books. Each notice shall state:

If notice of redemption has been given and we have set aside the funds necessary for such redemption in trust for the benefit of the holders of any shares so called for redemption, then from and after the redemption date, dividends will cease to accrue on such shares, and all rights of the holders of such shares will terminate, except the right to receive the redemption price.

Upon any voluntary or involuntary liquidation, dissolution or winding up of our affairs, then, before we make any distribution or payment to the holders of any common stock or any other class or series of our capital stock ranking junior to the preferred stock in the distribution of assets upon any liquidation, dissolution or winding up of our affairs, the holders of each series of preferred stock shall be entitled to receive out of assets legally available for distribution to stockholders, liquidating distributions in the amount of the liquidation preference per share set forth in the applicable prospectus supplement, plus any accrued and unpaid dividends thereon. Such dividends will not include any accumulation in respect of unpaid noncumulative dividends for prior dividend periods. After payment of the full amount of their liquidating distributions, the holders of preferred stock will have no right or claim to any of our remaining assets. Upon any such voluntary or involuntary liquidation, dissolution or winding up, if our available assets are insufficient to pay the amount of the liquidating distributions on all outstanding preferred stock and the corresponding amounts payable on all other classes or series of our capital stock ranking on parity with the preferred stock and all other such classes or series of shares of capital stock ranking on parity with the preferred stock in the distribution of assets, then the holders of the preferred stock and all other such classes or series of capital stock will share ratably in any such distribution of assets in proportion to the full liquidating distributions to which they would otherwise be entitled.

Upon liquidation, dissolution or winding up and if we have made liquidating distributions in full to all holders of preferred stock, we will distribute our remaining assets among the holders of any other classes or series of capital stock ranking junior to the preferred stock according to their respective rights and preferences and, in each case, according to their respective number of shares. For such purposes, our consolidation or merger with or into any other corporation, trust or entity, or the sale, lease or conveyance of all or substantially all of our property or business will not be deemed to constitute a liquidation, dissolution or winding up of our affairs.

Holders of preferred stock will not have any voting rights, except as described in the next paragraph, as otherwise from time to time required by law or as indicated in the applicable prospectus supplement.

Unless otherwise provided for any series of preferred stock, so long as any preferred stock of a series remains outstanding, we will not, without the affirmative vote or consent of the holders of at least two-thirds of the preferred stock of such series outstanding at the time, given in person or by proxy, either in writing or at a meeting with each of such series voting separately as a class:

Notwithstanding the preceding bullet point, if the preferred stock remains outstanding with the terms thereof materially unchanged, the occurrence of any of the events described above shall not be deemed to materially and adversely affect the rights, preferences, privileges or voting power of holders of preferred stock, even if upon the occurrence of such an event we may not be the surviving entity. In addition, any increase in the amount of (1) authorized preferred stock or the creation or issuance of any other series of preferred stock, or (2) authorized shares of such series or any other series of preferred stock, in each case ranking on parity with or junior to the preferred stock of such series with respect to payment of dividends or the distribution of assets upon liquidation, dissolution or winding up, shall not be deemed to materially and adversely affect such rights, preferences, privileges or voting powers.

The foregoing voting provisions will not apply if, at or prior to the time when the act with respect to which such vote would otherwise be required will be effected, we have redeemed or called for redemption all outstanding shares of such series of preferred stock and, if called for redemption, have deposited sufficient funds in trust to effect such redemption.

The terms and conditions, if any, upon which any series of preferred stock is convertible into common stock will be set forth in the applicable prospectus supplement relating thereto. Such terms will include the number of shares of common stock into which the shares of preferred stock are convertible, the conversion price, rate or manner of calculation thereof, the conversion period, provisions as to whether conversion will be at our option or at the option of the holders of the preferred stock, the events requiring an adjustment of the conversion price and provisions affecting conversion in the event of the redemption.

The transfer agent and registrar for the preferred stock will be set forth in the applicable prospectus supplement.

We may issue warrants for the purchase of preferred stock or common stock. Warrants may be issued independently, together with any other securities offered by any prospectus supplement or through a dividend or other distribution to our stockholders and may be attached to or separate from such securities. We may issue warrants under a warrant agreement to be entered into between us and a warrant agent. We will name any warrant agent in the applicable prospectus supplement. The warrant agent will act solely as our agent in connection with the warrants of a particular series and will not assume any obligation or relationship of agency or trust for or with any holders or beneficial owners of warrants.

The following is a description of the general terms and provisions of any warrants we may issue and may not contain all the information that is important to you. You can access complete information by referring to the applicable prospectus supplement. In the applicable prospectus supplement, we will describe the terms of the warrants and applicable warrant agreement, including, where applicable, the following:

Any underwritten offering may be on a best efforts or a firm commitment basis. We may also make direct sales through subscription rights distributed to our stockholders on a pro rata basis, which may or may not be transferable. In any distribution of subscription rights to stockholders, if all of the underlying securities are not subscribed for, we may then sell the unsubscribed securities directly to third parties or may engage the services of one or more underwriters, dealers or agents, including standby underwriters, to sell the unsubscribed securities to third parties.

If a dealer is used in an offering of securities, we may sell the securities to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of sale.

The distribution of the securities may be effected from time to time in one or more transactions:

Any of the prices may represent a discount from or premium to the prevailing market prices.

In the sale of the securities, underwriters, dealers or agents may receive compensation from us or from purchasers of the securities, for whom they may act as agents, in the form of discounts, concessions or commissions. Underwriters may sell the securities to or through dealers, and such dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters and/or commissions from the purchasers for whom they may act as agents. Underwriters, dealers and agents that participate in the distribution of the securities may be deemed to be underwriters under the Securities Act and any discounts or commissions they receive from us and any profit on the resale of securities they realize may be deemed to be underwriting discounts and commissions under the Securities Act. The applicable prospectus supplement will, where applicable:

Unless otherwise specified in the related prospectus supplement, each series of securities will be a new issue with no established trading market, other than the common stock, which is quoted on the Nasdaq National Market. Any common stock sold pursuant to a prospectus supplement will be quoted on the Nasdaq National Market, subject to applicable notices. We may elect to apply for quotation or listing of any series of debt securities or preferred stock, respectively, on a quotation system or an exchange but we are not obligated to do so. It is possible that one or more underwriters may make a market in a series of securities, but such underwriters will not be obligated to do so and may discontinue any market making at any time without notice. Therefore, no assurance can be given as to the liquidity of, or the trading market for, any series of debt securities or preferred stock.

Until the distribution of the securities is completed, rules of the SEC may limit the ability of any underwriters and selling group members to bid for and purchase the securities. As an exception to these rules, underwriters are permitted to engage in some transactions that stabilize the price of the securities. Such transactions consist of bids or purchases for the purpose of pegging, fixing or maintaining the price of the securities.

If any underwriters create a short position in the securities in an offering in which they sell more securities than are set forth on the cover page of the applicable prospectus supplement, the underwriters may reduce that short position by purchasing the securities in the open market.

The lead underwriters may also impose a penalty bid on other underwriters and selling group members participating in an offering. This means that if the lead underwriters purchase securities in the open market to reduce the underwriters' short position or to stabilize the price of the securities, they may reclaim the amount of any selling concession from the underwriters and selling group members who sold those securities as part of the offering.

In general, purchases of a security for the purpose of stabilization or to reduce a short position could cause the price of the security to be higher than it might be in the absence of such purchases. The imposition of a penalty bid might also have an effect on the price of a security to the extent that it were to discourage resales of the security before the distribution is completed.

We do not make any representation or prediction as to the direction or magnitude of any effect that the transactions described above might have on the price of the securities. In addition, we do not make any representation that underwriters will engage in such transactions or that such transactions, once commenced, will not be discontinued without notice at any time.

Under agreements into which we may enter, underwriters, dealers and agents who participate in the distribution of the securities may be entitled to indemnification by us against certain civil liabilities, including liabilities under the Securities Act, or contribution from us to payments which the underwriters, dealers or agents may be required to make.

Underwriters, dealers and agents may engage in transactions with us or perform services for us in the ordinary course of business.

If indicated in the applicable prospectus supplement, securities may also be offered or sold by a "remarketing firm" in connection with a remarketing arrangement contemplated by the terms of the securities. Remarketing firms may act as principals for their own accounts or as agents. The applicable prospectus supplement will identify any remarketing firm and the terms of its agreement, if any, with us. It will also describe the remarketing firms compensation. Remarketing firms may be deemed to be underwriters in connection with the remarketing of the securities.

If indicated in the applicable prospectus supplement, we will authorize underwriters, dealers or other persons acting as our agents to solicit offers by particular institutions to purchase securities from us at the public offering price set forth in such prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on such future date or dates stated in such prospectus supplement. Each delayed delivery contract will be for an amount no less than, and the aggregate principal amounts of securities sold under delayed delivery contracts shall be not less nor more than, the respective amounts stated in the applicable prospectus supplement. Institutions with which such delayed delivery contracts, when authorized, may be made include commercial and savings banks, insurance companies, pension funds, investment companies, educational and charitable institutions and others, but will in all cases be subject to our approval. The obligations of any purchaser under any such contract will be subject to the conditions that (1) the purchase of the securities shall not at the time of delivery be prohibited under the laws of any jurisdiction in the United States to which the purchaser is subject, and (2) if the securities are being sold to underwriters, we shall have sold to the underwriters the total principal amount of the securities less the principal amount thereof covered by the delayed delivery contracts. The underwriters and such other agents will not have any responsibility in respect of the validity or performance of such delayed delivery contracts.

To comply with applicable state securities laws, the securities offered by this prospectus will be sold, if necessary, in such jurisdictions only through registered or licensed brokers or dealers. In addition, securities may not be sold in some states unless they have been registered or qualified for sale in the applicable state or an exemption from the registration or qualification requirement is available and is complied with.

The financial statements of SatCon Technology Corporation as of September 30, 2003 and 2002 and for each of the two years in the period ended September 30, 2003, incorporated by reference in this prospectus and elsewhere in the Registration Statement, have been audited by Grant Thornton LLP, independent certified public accountants, as indicated in their report with respect thereto, and are incorporated by reference herein in reliance upon the authority of said firm as experts in giving said reports.

The financial statements of SatCon Technology Corporation incorporated in this prospectus by reference to the financial statements for the year ended September 30, 2001, included in the Annual Report on Form 10-K for the year ended September 30, 2003, were audited by Arthur Andersen LLP, independent public accountants, as indicated in their reports with respect thereto, and are included herein in reliance upon the authority of said firm as experts in giving said reports. We have not obtained a reissued report from Arthur Andersen and have been unable to obtain, after reasonable efforts, Arthur Andersen's written consent to the inclusion of their reports in this prospectus, and we have dispensed with the requirement to file their consent in reliance on Rule 437a promulgated under the Securities Act of 1933. Because Arthur Andersen has not consented to the inclusion of their reports in this prospectus, investors will not be able to recover against Arthur Andersen under Section 11 of the Securities Act of 1933. In addition, the ability of Arthur Andersen to satisfy any claims (including claims arising from its provision of auditing and other services to us) may be limited as a result of the diminished amount of assets of Arthur Andersen that are or may in the future be available to satisfy claims.

Certain legal matters, including the legality of the securities offered, will be passed upon for us by our counsel, Greenberg Traurig, LLP, Boston, Massachusetts.

Risk Factors		1
Special Statement Regarding Forward Looking-Information		11
About this Prospectus		11
About SatCon Technology Corporation		12
Where You Can Find More Information		12
Incorporation of Documents by Reference		12
Ratio of Earnings to Combined Fixed Charges and Preferred Dividends		13
How we Intend to Use the Proceeds		14
Description of the Securities		15
Description of Common Stock		16
Description of Preferred Stock		18
Description of Warrants		24
How We Plan to Sell the Securities		25
Experts		27
Legal Matters		27