IMPORTANT NOTICE 
 
 
THE PURPOSE OF THIS SCHEDULE 13G AMENDMENT IS TO CORRECT THE DATES ONLY. 
 
PLEASE NOTE FMR CORP. HOLDINGS ARE AS OF JUNE 30, 1994 AND NOT MAY 31, 1994 AS 
INDICATED. 


SCHEDULE 13G 
 
Amendment No. 8 
Orbital Sciences Corporation 
common stock 
Cusip # 685564106 
Filing Fee: No 


Cusip # 685564106 
Item 1:	Reporting Person - FMR Corp. - (Tax ID:  04-2507163) 
Item 4:	Commonwealth of Massachusetts 
Item 5:	67,000 
Item 6:	None 
Item 7:	523,564 
Item 8:	None 
Item 9:	523,564 
Item 11:	3.47% 
Item 12:	HC  
 
 


Cusip # 685564106 
Item 1:	Reporting Person - Edward C. Johnson 3d - (Tax ID:  ###-##-####) 
Item 4:	United States of America 
Item 5:	None 
Item 6:	None 
Item 7:	523,564 
Item 8:	None 
Item 9:	523,564 
Item 11:	3.47% 
Item 12:	IN  
 
 


SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS 
FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b) 
 
 
Item 1(a).	Name of Issuer: 
 
		Orbital Sciences Corporation 
 
Item 1(b).	Name of Issuer's Principal Executive Offices: 
 
		21700 Atlantic Boulevard  
		Dullas, VA  20166 
 
Item 2(a).	Name of Person Filing:  
 
		FMR Corp. 
 
Item 2(b).	Address or Principal Business Office or, if None, Residence: 
 
		82 Devonshire Street, Boston, Massachusetts  02109 
 
Item 2(c).	Citizenship: 
 
		Not applicable 
 
Item 2(d).	Title of Class of Securities: 
 
		Common Stock 
 
Item 2(e).	CUSIP Number:   
 
		685564106 
 
Item 3.	This statement is filed pursuant to Rule 13d-1(b) or 13d-2(b) and the 
person filing, FMR Corp., is a parent holding company in accordance 
with Section 240.13d-1(b)(ii)(G).  (Note:  See Item 7). 
 
Item 4.	Ownership 
 
	(a)	Amount Beneficially Owned:
	523,564 
 
	(b)	Percent of Class:
	3.47% 
 
	(c)	Number of shares as to which such person has:   
 
	(i)	sole power to vote or to direct the vote:
	67,000 
 
	(ii)	shared power to vote or to direct the vote:
	None 
 
	(iii)	sole power to dispose or to direct the disposition of:
	523,564 
 
	(iv)	shared power to dispose or to direct the disposition of:
	None 
 
 


Item 5.	Ownership of Five Percent or Less of a Class. 
 
	If this statement is being filed to report the fact that as of 
the date hereof, the reporting person has ceased to be the 
beneficial owner of more than five percent of the class of 
securities, check the following (X). 
 
Item 6.	Ownership of More than Five Percent on Behalf of Another Person. 
 
	Not applicable. 
 
Item 7.	Identification and Classification of the Subsidiary Which Acquired 
the Security Being Reported on By the Parent Holding Company. 
 
	See attached Exhibit(s) A and B. 
 
Item 8.	Identification and Classification of Members of the Group. 
 
	Not applicable, see attached Exhibit A.  
 
Item 9.	Notice of Dissolution of Group. 
 
	Not applicable. 


Item 10.	Certification. 
 
	Inasmuch as the reporting persons are no longer the beneficial 
owners of more than five percent of the number of shares 
outstanding, the reporting persons have no further reporting 
obligation under section 13(d) of the Securities and Exchange 
Commission thereunder, and the reporting persons have no 
obligation to amend this Statement if any material change 
occurs in the facts set forth herein. 
 
 
Signature 
 
	After reasonable inquiry and to the best of my knowledge and 
belief, I certify that the information set forth in this 
Schedule 13G in connection with FMR Corp's beneficial ownership 
of the common stock of Orbital Sciences Corporation at May 31, 
1994 is true, complete and correct.  
 
 
 
	June 6, 1994	 
Date 
 
 
 
	/s/Arthur S. Loring 
Signature 
 
 
 
	Arthur S. Loring, Vice 
President	 
Name/Title 
 
 


SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS 
FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b) 
 
	Pursuant to the instructions in Item 7 of Schedule 13G, Fidelity 
Management & Research Company ("Fidelity"), 82 Devonshire Street, Boston, 
Massachusetts 02109, a wholly-owned subsidiary of FMR Corp. and an investment 
adviser registered under Section 203 of the Investment Advisers Act of 1940, 
is the beneficial owner of 456,564 shares or 3.03% of the common stock 
outstanding of Orbital Sciences Corporation ("the Company") as a result of 
acting as investment adviser to several investment companies registered under 
Section 8 of the Investment Company Act of 1940.  The number of shares of 
common stock of Orbital Sciences Corporation owned by the investment companies 
at May 31, 1994 included 335,164 shares of common stock resulting from the 
assumed conversion of $4,818,000 principal amount of 6.75% Convertible 
Subordinated Debenture (69.5652 shares of common stock for each $1,000 
principal amount of debenture). 
 
	Edward C. Johnson 3d, FMR Corp., through its control of Fidelity, and the 
Funds each has sole power to dispose of the 456,564 shares owned by the Funds. 
 
	Neither FMR Corp. nor Edward C. Johnson 3d, Chairman of FMR Corp., has 
the sole power to vote or direct the voting of the shares owned directly by 
the Fidelity Funds, which power resides with the Funds' Boards of Trustees.  
Fidelity carries out the voting of the shares under written guidelines 
established by the Funds' Boards of Trustees. 
 
	Fidelity Management Trust Company, 82 Devonshire Street, Boston, 
Massachusetts 02109, a wholly-owned subsidiary of FMR Corp. and a bank as 
defined in Section 3(a)(6) of the Securities Exchange Act of 1934, is the 
beneficial owner of 67,000 shares or 0.44% of the common stock outstanding of 
the company as a result of its serving as investment manager of the 
institutional account(s).   
 
	FMR Corp., through its control of Fidelity Management Trust Company, has 
sole voting and dispositive power over 67,000 shares of common stock owned by 
the institutional account(s) as reported above. 
 
	Edward C. Johnson 3d owns 34.0% of the outstanding voting common stock of 
FMR Corp.  Mr. Johnson 3d is Chairman of FMR Corp.  Various Johnson family 
members and trusts for the benefit of Johnson family members own FMR Corp. 
voting common stock.  These Johnson family members, through their ownership of 
voting common stock, form a controlling group with respect to FMR Corp. 
 


SCHEDULE 13G - TO BE INCLUDED IN STATEMENTS 
FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b) 
 
RULE 13d-1(e)  AGREEMENT 
 
	The undersigned persons, on June 6, 1994, agree and consent to the joint 
filing on their behalf of this Schedule 13G in connection with their 
beneficial ownership of the common stock of Orbital Sciences Corporation at 
May 31, 1994. 
 
	FMR Corp. 
	By	/s/Arthur S. Loring 
Arthur S. Loring
Vice President - Legal 
		Edward C. Johnson 3d 
	By	/s/Arthur S. Loring 
Arthur S. Loring
Under Power of Attorney dated 
5/17/89
On File with Schedule 13G for
Airborne Freight Corp. 9/10/91 
	Fidelity Management & Research Company 
	By	/s/Arthur S. Loring 
Arthur S. Loring
Sr. V.P. and General Counsel