ACCOUNTANTS' CONSENT The Board of Directors Orbital Sciences Corporation We consent to the incorporation by reference in the Registration Statement on Form S-8 dated August 31, 1995 of Orbital Sciences Corporation of our report dated May 25, 1995, except as to note 8(d) which is at September 29, 1995, with respect to the consolidated balance sheets of MacDonald, Dettwiler and Associates Ltd. as at March 31, 1995 and 1994, and the related consolidated statements of earnings, retained earnings and changes in financial position for each of the years in the three year period ended March 31, 1995, which report appears in the Form 8-K of Orbital Sciences Corporation dated October 19, 1995. (Signed) KPMG Peat Marwick Thorne Chartered Accountants Vancouver, Canada October 19, 1995