Summary of ORBITAL SCIENCES CORP /DE/

Item 5.02 Departure of Directors or Certain Officers; Election of Directors;
Appointment of Certain Officers; Compensatory Arrangements of Certain Officers.

As noted below under Item 5.07, on April 25, 2012, the stockholders of Orbital Sciences Corporation ("Orbital" or the "Company") approved an amendment and restatement of Orbital's 2005 Stock Incentive Plan (the "Amended 2005 Plan"). Orbital's Board of Directors previously approved the Amended 2005 Plan on January 26, 2012, subject to stockholder approval.

The Amended 2005 Plan increases the number of shares of Orbital common stock authorized for issuance by 2.5 million, thereby increasing the total number of shares authorized to 5 million. The Amended 2005 Plan also contains a number of revisions to its terms to conform to changing applicable law and regulations and current corporate governance practices. A description of the Amended 2005 Plan is set forth under "Proposal 4 - Approval of the Orbital Sciences Corporation Amended and Restated 2005 Stock Incentive Plan" in the Company's amended and restated definitive proxy statement filed with the Securities and Exchange Commission on March 15, 2012, and is incorporated herein by reference. A copy of the Amended 2005 Plan is attached hereto as Exhibit 10.1 and is incorporated herein by reference.

Item 5.07 Submission of Matters to a Vote of Security Holders.

Orbital held its annual meeting of stockholders on April 25, 2012 (the "Annual Meeting"). At the Annual Meeting, four proposals were submitted to, and approved by, Orbital's stockholders. The proposals are described in more detail in Orbital's amended and restated definitive proxy statement for the Annual Meeting filed with the Commission on March 15, 2012. The final voting results were as follows:

Proposal 1

Orbital's stockholders elected the following five directors to serve for
three-year terms expiring at the 2015 annual meeting of stockholders and until
their respective successors are elected and qualified or until their death,
removal or resignation. The voting results are set forth below.

                       For              Against           Abstain   Broker Non-Vote
Robert M. Hanisee   46,322,917                1,090,881   54,740       5,707,118
James G. Roche      47,081,585                 342,189    54,764       5,707,118
Harrison H. Schmitt 44,939,899                2,484,217   54,422       5,707,118
James R. Thompson   45,655,198                1,765,195   58,145       5,707,118
Scott L. Webster    38,574,888               8,858,358    45,292       5,707,118

Proposal 2

Orbital's stockholders ratified the appointment of PricewaterhouseCoopers LLP as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2012. The voting results are set forth below.

For Against Abstain Broker Non-Vote 51,412,873 1,747,167 25,616 -

Proposal 3

Orbital's stockholders approved, by an advisory vote, the compensation paid to the Company's named executive officers. The voting results are set forth below.

For Against Abstain Broker Non-Vote 43,805,988 3,606,114 66,436 5,707,118

Proposal 4

As described above, Orbital's stockholders approved a proposal to amend and restate the Company's 2005 Stock Incentive Plan. The voting results are set forth below.

For Against Abstain Broker Non-Vote 40,513,736 6,899,115 65,687 5,707,118

Item 9.01. Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.   Description

   10.1       Orbital Sciences Corporation Amended and Restated
              2005 Stock Incentive Plan.

   10.2       Form of Stock Unit Agreement under the Amended and
              Restated 2005 Stock Incentive Plan.