SEC Form 4
FORM 4 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
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 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
1. Name and Address of Reporting Person*
THOMPSON JAMES R JR
(Last) (First) (Middle)
21839 ATLANTIC BOULEVARD
(Street)
DULLES VA 20166
(City) (State) (Zip)
2. Issuer Name and Ticker or Trading Symbol
ORBITAL SCIENCES CORP /DE/ [ ORB ] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
X Director 10% Owner
X Officer (give title below) Other (specify below)
VC, President and COO
3. Date of Earliest Transaction (Month/Day/Year)
03/08/2006
4. If Amendment, Date of Original Filed (Month/Day/Year)
 6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 03/08/2006 M 10,000 A $13.5 270,429 D
Common Stock 03/08/2006 M 30,000 A $3.45 300,429 D
Common Stock 03/08/2006 S 4,000 D $14.73 296,429 D
Common Stock 03/08/2006 S 400 D $14.71 296,029 D
Common Stock 03/08/2006 S 900 D $14.7 295,129 D
Common Stock 03/08/2006 S 600 D $14.68 294,529 D
Common Stock 03/08/2006 S 200 D $14.67 294,329 D
Common Stock 03/08/2006 S 200 D $14.66 294,129 D
Common Stock 03/08/2006 S 5,200 D $14.65 288,929 D
Common Stock 03/08/2006 S 1,100 D $14.6 287,829 D
Common Stock 03/08/2006 S 200 D $14.59 287,629 D
Common Stock 03/08/2006 S 200 D $14.58 287,429 D
Common Stock 03/08/2006 S 300 D $14.57 287,129 D
Common Stock 03/08/2006 S 300 D $14.56 286,829 D
Common Stock 03/08/2006 S 200 D $14.55 286,629 D
Common Stock 03/08/2006 S 1,300 D $14.54 285,329 D
Common Stock 03/08/2006 S 100 D $14.53 285,229 D
Common Stock 03/08/2006 S 200 D $14.52 285,029 D
Common Stock 03/08/2006 S 100 D $14.48 284,929 D
Common Stock 03/08/2006 S 1,400 D $14.47 283,529 D
Common Stock 03/08/2006 S 3,700 D $14.46 279,829 D
Common Stock 03/08/2006 S 500 D $14.43 279,329 D
Common Stock 03/08/2006 S 400 D $14.42 278,929 D
Common Stock 03/08/2006 S 1,800 D $14.41 277,129 D
Common Stock 03/08/2006 S 7,100 D $14.4 270,029 D
Common Stock 03/08/2006 S 100 D $14.39 269,929 D
Common Stock 03/08/2006 S 800 D $14.37 269,129 D
Common Stock 03/08/2006 S 1,400 D $14.36 267,729 D
Common Stock 03/08/2006 S 1,600 D $14.35 266,129 D
Common Stock 03/08/2006 S 800 D $14.34 265,329 D
Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 6. Date Exercisable and Expiration Date (Month/Day/Year) 7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Option (right to buy) $13.5 03/08/2006 M 10,000 05/03/1997(1) 05/02/2006 Common Stock 10,000 $0.00 0 D
Stock Option (right to buy) $3.45 03/08/2006 M 30,000 12/04/2002(2) 12/04/2011 Common Stock 30,000 $0.00 0 D
Explanation of Responses:
1. The option vested in three installments on May 3, 1997, May 3, 1998 and May 3, 1999.
2. The options vested in two equal installments on December 4, 2002 and December 4, 2003.
Remarks:
This Form 4 dated March 10, 2006 is part 1 of 2 Form 4s dated March 10, 2006 and should be read in conjunction with the other Form 4. The total number of transactions exceeded the 30 transactions per report limitation imposed by the SEC on electronic filings. The two Form 4s shall be one for reporting purposes.
/s/ James R. Thompson, Jr. by Vanessa T. Hoang, Attorney-in-Fact 03/10/2006
** Signature of Reporting Person Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.