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FILED PURSUANT TO
RULE 424(B)(3)
FILE NO. 333-42271
PROSPECTUS SUPPLEMENT DATED APRIL 7, 1998
TO PROSPECTUS DATED MARCH 12, 1998
ORBITAL SCIENCES CORPORATION
5% CONVERTIBLE SUBORDINATED NOTES DUE 2002
SELLING SECURITYHOLDERS
This Prospectus Supplement should be read in conjunction with the
Prospectus dated March 12, 1998 (the "Prospectus"). The table on pages 30, 31
and 32 of the Prospectus setting forth information concerning the Selling
Securityholders is superceded by the following table:
<TABLE>
<CAPTION>
COMMON
PRINCIPAL PRINCIPAL STOCK
AMOUNT OF AMOUNT OF NOTES OWNED PRIOR COMMON STOCK
NAME OF SELLING SECURITYHOLDER NOTES OWNED OFFERED HEREBY TO OFFERING(1) OFFERED HEREBY(2)
------------------------------ ----------- --------------- -------------- -----------------
<S> <C> <C> <C> <C>
Merrill Lynch International.............. 13,050,000 13,050,000 466,071 466,071
General Motors Employees Domestic Group
Trust.................................. 10,680,000 10,680,000 381,428 381,428
The Strategic Money Management Company
B.V. .................................. 8,300,000 8,300,000 296,428 296,428
Bankers Trust International.............. 5,450,000 5,450,000 194,642 194,642
Bond Fund Series Oppenheimer Bond Fund
For Growth............................. 4,500,000 4,500,000 160,714 160,714
J.P. Morgan Securities Inc.(3)........... 3,550,000 3,550,000 126,785 126,785
Delaware State Employees Retirement
Fund................................... 3,025,000 3,025,000 108,035 108,035
Societe Generale Securities Corp. ....... 2,750,000 2,750,000 98,214 98,214
Deutsche Morgan Grenfell Inc.(4)......... 2,725,000 2,725,000 97,321 97,321
SMALLCAP World Fund, Inc. ............... 2,500,000 2,500,000 89,285 89,285
Paloma Securities L.L.C. ................ 2,170,000 2,170,000 77,500 77,500
Chrysler Corporation Master Retirement
Trust.................................. 2,050,000 2,050,000 73,214 73,214
Allstate Insurance Company............... 2,000,000 2,000,000 95,928(5) 71,428
Lipper Offshore Convertibles, L.P. ...... 2,000,000 2,000,000 71,428 71,428
The Northwestern Mutual Life Insurance
Company................................ 2,000,000 2,000,000 71,428 71,428
Vanguard Convertible Securities Fund,
Inc.................................... 1,850,000 1,850,000 66,071 66,071
Froley, Revy Investment Co. Inc.
Account: Arkansas PERS................. 1,560,000 1,560,000 55,714 55,714
Lipper Convertibles, L.P. ............... 1,500,000 1,500,000 53,571 53,571
Froley, Revy Investment Co. Inc.
Account: Delaware PERS................. 1,350,000 1,350,000 48,214 48,214
Silverton International Fund Limited..... 1,330,000 1,330,000 47,500 47,500
Equitable Life Assurance Separate Account
Convertibles........................... 1,305,000 1,305,000 46,607 46,607
AAM/ZAZOVE Institutional Income Fund,
L.P. .................................. 1,300,000 1,300,000 46,428 46,428
Alexandra Global Investment Fund 1,
Ltd. .................................. 1,300,000 1,300,000 46,428 46,428
Husic Capital Management as a
Discretionary Asset Manager for the
Ameritech Pension Plan under an
Investment Management Agreement dated
December 22, 1995...................... 1,000,000 1,000,000 35,714 35,714
The Minnesota Mutual Life Insurance
Company................................ 1,000,000 1,000,000 35,714 35,714
Hudson River Trust Growth & Income
Account................................ 945,000 945,000 33,750 33,750
Orrington Investments L.P. .............. 937,000 937,000 33,464 33,464
</TABLE>
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<TABLE>
<CAPTION>
COMMON
PRINCIPAL PRINCIPAL STOCK
AMOUNT OF AMOUNT OF NOTES OWNED PRIOR COMMON STOCK
NAME OF SELLING SECURITYHOLDER NOTES OWNED OFFERED HEREBY TO OFFERING(1) OFFERED HEREBY(2)
------------------------------ ----------- --------------- -------------- -----------------
<S> <C> <C> <C> <C>
Declaration of Trust for the Defined
Benefit Plan of ICI American Holdings,
Inc. .................................. 925,000 925,000 33,035 33,035
State Employees' Retirement Fund of the
State of Delaware...................... 900,000 900,000 32,142 32,142
Thermo Electron Balanced Investment
Fund................................... 830,000 830,000 29,642 29,642
Hudson River Trust Balanced Account...... 690,000 690,000 24,642 24,642
Declaration of Trust for the Defined
Benefit Plan of ZENECA Holdings
Inc. .................................. 640,000 640,000 22,857 22,857
Memphis Light, Water and Gas Retirement
Fund................................... 615,000 615,000 21,964 21,964
The J.W. McConnell Family Foundation..... 585,000 585,000 20,892 20,892
Orrington International Fund Ltd. ....... 563,000 563,000 20,106 20,106
Froley, Revy Investment Co. Inc.
Account: ICI American Holdings Trust... 545,000 545,000 19,464 19,464
Froley, Revy Investment Co. Inc.
Account: Zeneca Holdings Trust......... 545,000 545,000 19,464 19,464
Hudson River Trust Growth Investors...... 545,000 545,000 19,464 19,464
Combined Insurance Company of America.... 500,000 500,000 17,857 17,857
Black Diamond Partners, L.P. ............ 460,000 460,000 16,428 16,428
Black Diamond Ltd. ...................... 429,000 429,000 15,321 15,321
Bancroft Convertible Fund, Inc. ......... 350,000 350,000 12,500 12,500
Ellsworth Convertible Growth and Income
Fund, Inc. ............................ 350,000 350,000 12,500 12,500
Hillside Capital Incorporated Corporate
Account................................ 275,000 275,000 9,821 9,821
Froley, Revy Investment Co. Inc.
Account: Nalco Chemical Retirement
Trust.................................. 250,000 250,000 8,928 8,928
First Church of Christ, Scientist --
Endowment.............................. 245,000 245,000 8,750 8,750
Christian Science Trustees for Gifts and
Endowments............................. 225,000 225,000 8,035 8,035
FJH Absolute Return Fund, L.P. .......... 200,000 200,000 7,142 7,142
Partner Reinsurance Company, Ltd. ....... 200,000 200,000 7,142 7,142
The Frist Foundation..................... 160,000 160,000 5,714 5,714
Forum Capital Markets L.P................ 150,000 150,000 5,357 5,357
Equitable Life Assurance Separate Account
Balanced............................... 70,000 70,000 2,500 2,500
Summer Hill Global Partners, L.P. ....... 70,000 70,000 2,500 2,500
Worldwide Transactions Ltd. ............. 63,000 63,000 2,250 2,250
Highbridge Capital Corp. ................ 48,000 48,000 1,714 1,714
David Lipscomb University General
Endowment.............................. 40,000 40,000 1,428 1,428
SUBTOTAL........................ $ 93,595,000 $ 93,595,000 3,367,155 3,342,655
------------ ------------ --------- ---------
Unnamed holders of Notes or any future
transferees, pledgees, donees or
successors of or from any such unnamed
holders(6)............................. $ 6,405,000 $ 6,405,000 228,773(7) 228,773
TOTAL........................... $100,000,000 $100,000,000 3,595,928 3,571,428
============ ============ ========= =========
</TABLE>
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(1) Comprises the shares of Common Stock owned by each Selling Securityholder
prior to the offering, including the shares of Common Stock into which the
Notes held by such Selling Securityholder are convertible at the initial
conversion rate, excluding fractional shares. Fractional shares will not be
issued upon conversion of the Notes; rather, cash will be paid in lieu of
fractional shares, if any. The Conversion
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Rate and the number of shares of Common Stock issuable upon conversion of
the Notes are subject to adjustment under certain circumstances. See
"Description of Notes -- Conversion Rights." Accordingly, the number of
shares of Common Stock issuable upon conversion of the Notes may increase or
decrease from time to time.
(2) Assumes conversion into Common Stock of the full amount of Notes held by the
Selling Securityholder at the initial conversion rate and the offering of
such shares by such Selling Securityholder pursuant to this Prospectus. The
Conversion Rate and the number of shares of Common Stock issuable upon
conversion of the Notes is subject to adjustment under certain
circumstances. See "Description of Notes -- Conversion Rights." Accordingly,
the number of shares of Common Stock issuable upon conversion of the Notes
may increase or decrease from time to time. Fractional shares will not be
issued upon conversion of the Notes; rather, cash will be paid in lieu of
fractional shares, if any. The Selling Securityholders may offer and sell
pursuant to the Prospectus, their Notes, their Conversion Shares or both.
(3) J.P. Morgan Securities Inc. acted as an Initial Purchaser in the original
placement of the Notes. In addition, Morgan Guaranty Trust Company of New
York, an affiliate of J.P. Morgan Securities Inc., acts as an administrative
agent and collateral agent for a syndicate of six banks which provide a
credit facility to the Company.
(4) Deutsche Morgan Grenfell, Inc. ("DMG") acted as an Initial Purchaser in the
original placement of the Notes. In addition, Deutsche Bank AG, New York
Branch, an affiliate of DMG, is the trustee under the Indenture for the
Notes. In addition, Deutsche Bank, another affiliate of DMG, provides an
uncommitted $25 million demand line of credit to the Company.
(5) Does not include (i) 5,800 shares of Common Stock owned by CTC Illinois
Trust Company, as trustee for the Allstate Retirement Plan, or (ii) 3,800
shares of Common Stock owned by CTC Illinois Trust Company, as trustee for
Agents Pension Plan.
(6) No such holder may offer Notes pursuant to this Prospectus until such holder
is included as a Selling Securityholder in a supplement to this Prospectus
in accordance with the Registration Rights Agreement.
(7) Assumes that the unnamed holders of Notes or any future transferees,
pledgees, donees or successors of or from any such unnamed holder do not
beneficially own any Common Stock other than the Common Stock issuable upon
conversion of the Notes at the initial conversion rate.
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