----

----

| þ | QUARTERLY      REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF      1934 |
|--------|---------------------------------------------------------------------------------------------------|
|   | For      the quarterly period ended June 30,2009                                                  |

| o      | TRANSITION      REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIESEXCHANGE      ACT OF 1934 |
|--------|---------------------------------------------------------------------------------------------------|
|   | For      the transition period from ______ to______                                               |

| Delaware                                    | 06-1209561                                |
|---------------------------------------------|-------------------------------------------|
| (State      of Incorporation of Registrant) | (I.R.S.      Employer Identification No.) |

----

----

----

|   | ITEM      1.   FINANCIALSTATEMENTS |
|--------|---------------------------------------------------|

|   | ORBITAL      SCIENCES CORPORATION |
|--------|-----------------------------------|

|                                                                                                  |   | June      30, |    |   | December      31,  |   |
|-------------------------------------------------------------------------------------------------------|--------|---------------|---------|--------|--------------------|--------|
|                                                                                                  |   | 2009          |    |   | 2008               |   |
|                                                                                                  |   |          |    |   | (As      Adjusted) |   |
| ASSETS                                                                                                |   |          |    |   |               |   |
| Current      assets:                                                                                  |   |          |    |   |               |   |
|   Cash      and cash equivalents                                                            |   | $             | 340,287 |   |               | $      | 328,307 |   |
|   Receivables,      net                                                                     |   |          | 217,740 |   |               |   | 203,111 |   |
|   Inventories,      net                                                                     |   |          | 44,941  |   |               |   | 33,434 |   |
|   Deferred      income taxes, net                                                           |   |          | 39,331  |   |               |   | 35,368 |   |
|   Other      current assets                                                                 |   |          | 3,533   |   |               |   | 8,951 |   |
| Total      current assets                                                                             |   |          | 645,832 |   |               |   | 609,171 |   |
| Investments                                                                                           |   |          | 14,700  |   |               |   | 16,700 |   |
| Property, plant and equipment,      net                                                               |   |          | 115,932 |   |               |   | 104,880 |   |
| Goodwill                                                                                              |   |          | 55,551  |   |               |   | 55,551 |   |
| Deferred income taxes,      net                                                                       |   |          | 52,248  |   |               |   | 63,206 |   |
| Other      non-current assets                                                                         |   |          | 24,848  |   |               |   | 4,387 |   |
| Total      assets                                                                                     |   | $             | 909,111 |   |               | $      | 853,895 |   |
|                                                                                                  |   |          |    |   |               |   |   |   |
| LIABILITIES      AND STOCKHOLDERS’ EQUITY                                                       |   |          |    |   |               |   |   |   |
| Current      liabilities:                                                                             |   |          |    |   |               |   |   |   |
|   Accounts      payable and accrued expenses                                                |   | $             | 149,646 |   |               | $      | 179,658 |   |
|   Deferred      revenues and customer advances                                              |   |          | 152,928 |   |               |   | 80,059 |   |
| Total      current liabilities                                                                        |   |          | 302,574 |   |               |   | 259,717 |   |
| Long-term      obligations                                                                            |   |          | 117,780 |   |               |   | 115,372 |   |
| Other      non-current liabilities                                                                    |   |          | 8,170   |   |               |   | 5,700 |   |
| Total      liabilities                                                                                |   |          | 428,524 |   |               |   | 380,789 |   |
| Commitments      and contingencies                                                                    |   |          |    |   |               |   |   |   |
| Stockholders’      equity:                                                                      |   |          |    |   |               |   |   |   |
|   Preferred      Stock, par value $.01; 10,000,000 shares authorized, none      outstanding |   |          | — |   |               |   | — |   |
|   Common      Stock, par value $.01; 200,000,000 shares authorized, 56,482,376      and     |   |          |    |   |               |   |   |   |
|     57,499,260      shares outstanding, respectively                              |   |          | 565     |   |               |   | 575 |   |
|   Additional      paid—in capital                                                     |   |          | 537,214 |   |               |   | 547,389 |   |
|   Accumulated      other comprehensive loss                                                 |   |          | (3,088  | )      |               |   | (2,813 | ) |
|   Accumulated      deficit                                                                  |   |          | (54,104 | )      |               |   | (72,045 | ) |
| Total      stockholders’ equity                                                                 |   |          | 480,587 |   |               |   | 473,106 |   |
| Total      liabilities and stockholders’ equity                                                 |   | $             | 909,111 |   |               | $      | 853,895 |   |

----

|                                                       |   | Quarters      Ended June 30, |    |   | Six      Months Ended June 30, |   |
|------------------------------------------------------------|--------|------------------------------|---------|--------|--------------------------------|--------|
|                                                       |   | 2009                         |    |   | 2008                           |   |   | 2009 |   |   | 2008 |   |
|                                                       |   |                         |    |   | (As      Adjusted)             |   |   |   |   |   | (As      Adjusted) |   |
| Revenues                                                   |   | $                            | 270,129 |   |                           | $      | 301,223 |   |   | $ | 565,870 |   |   | $ | 584,768 |   |
| Cost      of revenues                                      |   |                         | 208,815 |   |                           |   | 242,789 |   |   |   | 455,163 |   |   |   | 477,471 |   |
| Research      and development expenses                     |   |                         | 30,734  |   |                           |   | 10,202 |   |   |   | 49,705 |   |   |   | 18,406 |   |
| Selling,      general and administrative expenses          |   |                         | 17,759  |   |                           |   | 21,745 |   |   |   | 37,017 |   |   |   | 42,413 |   |
| Income      from operations                                |   |                         | 12,821  |   |                           |   | 26,487 |   |   |   | 23,985 |   |   |   | 46,478 |   |
| Investment      impairment charge                          |   |                         | (600    | )      |                           |   | (10,600 | ) |   |   | (1,300 | ) |   |   | (10,600 | ) |
| Interest      income and other                             |   |                         | 1,750   |   |                           |   | 1,452 |   |   |   | 7,413 |   |   |   | 3,838 |   |
| Interest      expense                                      |   |                         | (2,157  | )      |                           |   | (2,187 | ) |   |   | (4,414 | ) |   |   | (4,321 | ) |
| Income      from continuing operations before income taxes |   |                         | 11,814  |   |                           |   | 15,152 |   |   |   | 25,684 |   |   |   | 35,395 |   |
| Income      tax provision                                  |   |                         | (3,075  | )      |                           |   | (5,041 | ) |   |   | (7,743 | ) |   |   | (13,222 | ) |
| Income      from continuing operations                     |   |                         | 8,739   |   |                           |   | 10,111 |   |   |   | 17,941 |   |   |   | 22,173 |   |
| Income      from discontinued operations, net of taxes     |   |                         | — |   |                           |   | 14,969 |   |   |   | — |   |   |   | 15,918 |   |
| Net      income                                            |   | $                            | 8,739   |   |                           | $      | 25,080 |   |   | $ | 17,941 |   |   | $ | 38,091 |   |
|                                                       |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
| Basic      income per share:                               |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
| Income      from continuing operations                     |   | $                            | 0.15    |   |                           | $      | 0.17 |   |   | $ | 0.31 |   |   | $ | 0.37 |   |
| Income      from discontinued operations                   |   |                         | — |   |                           |   | 0.25 |   |   |   | — |   |   |   | 0.27 |   |
| Net      income                                            |   |                         | 0.15    |   |                           |   | 0.42 |   |   |   | 0.31 |   |   |   | 0.64 |   |
|                                                       |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
| Diluted      income per share:                             |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
| Income      from continuing operations                     |   | $                            | 0.15    |   |                           | $      | 0.17 |   |   | $ | 0.31 |   |   | $ | 0.36 |   |
| Income      from discontinued operations                   |   |                         | — |   |                           |   | 0.24 |   |   |   | — |   |   |   | 0.26 |   |
| Net      income                                            |   |                         | 0.15    |   |                           |   | 0.41 |   |   |   | 0.31 |   |   |   | 0.62 |   |

----

|                                                                                                    |   | Six      Months Ended June 30, |    |
|---------------------------------------------------------------------------------------------------------|--------|--------------------------------|---------|
|                                                                                                    |   | 2009                           |    |   | 2008 |   |
|                                                                                                    |   |                           |    |   | (As      Adjusted) |   |
| Operating      Activities:                                                                              |   |                           |    |   |   |   |
|   Net      income                                                                             |   | $                              | 17,941  |   |   | $ | 38,091 |   |
|   Adjustments      to reconcile net income to net cash provided by operating      activities: |   |                           |    |   |   |   |   |   |
|       Gain      on sale of business, net of tax                           |   |                           | — |   |   |   | (14,800 | ) |
|       Investment      impairment charge                                   |   |                           | 1,300   |   |   |   | 10,600 |   |
|       Depreciation      expense                                           |   |                           | 9,632   |   |   |   | 9,156 |   |
|       Deferred      income taxes                                          |   |                           | 6,668   |   |   |   | 10,091 |   |
|       Stock-based      compensation and other                             |   |                           | 6,683   |   |   |   | 6,441 |   |
|   Changes      in assets and liabilities                                                      |   |                           | 2,093   |   |   |   | (16,656 | ) |
|      Net cash provided by operating      activities                            |   |                           | 44,317  |   |   |   | 42,923 |   |
|                                                                                                    |   |                           |    |   |   |   |   |   |
| Investing      Activities:                                                                              |   |                           |    |   |   |   |   |   |
|   Capital      expenditures                                                                   |   |                           | (18,357 | ) |   |   | (11,855 | ) |
|   Net      proceeds from sale of business                                                     |   |                           | — |   |   |   | 39,882 |   |
|   Net      proceeds from sale of property                                                     |   |                           | 100     |   |   |   | 2,193 |   |
|   Sale      of investment                                                                     |   |                           | 1,138   |   |   |   | — |   |
|   Other                                                                                       |   |                           | 84      |   |   |   | 1,081 |   |
|      Net      cash (used in) provided by investing activities                  |   |                           | (17,035 | ) |   |   | 31,301 |   |
|                                                                                                    |   |                           |    |   |   |   |   |   |
| Financing      Activities:                                                                              |   |                           |    |   |   |   |   |   |
|   Repurchase      of common stock                                                             |   |                           | (16,681 | ) |   |   | (15,131 | ) |
|   Net      proceeds from issuances of common stock                                            |   |                           | 1,262   |   |   |   | 6,216 |   |
|   Tax      benefit of stock-based compensation                                                |   |                           | 117     |   |   |   | 2,427 |   |
|      Net      cash used in financing activities                                |   |                           | (15,302 | ) |   |   | (6,488 | ) |
|                                                                                                    |   |                           |    |   |   |   |   |   |
| Net      increase in cash and cash equivalents                                                          |   |                           | 11,980  |   |   |   | 67,736 |   |
| Cash      and cash equivalents, beginning of period                                                     |   |                           | 328,307 |   |   |   | 235,822 |   |
| Cash      and cash equivalents, end of period                                                           |   | $                              | 340,287 |   |   | $ | 303,558 |   |

----

----

----

|                                                | Quarter      Ended June 30, 2008    |           |
|-----------------------------------------------------|-------------------------------------|----------------|
|                                                | Previously      Reported            | Adjustment     | As      Adjusted |
| Interest      expense                               |                                |  $(1,098) |   |   |  $(1,089) |   |   |  $(2,187) |   |
| Income      from continuing operations before taxes |                                |  16,241   |   |   |  (1,089) |   |   |  15,152 |   |
| Income      tax provision                           |                                |  (5,459)  |   |   |  418 |   |   |  (5,041) |   |
| Net      income                                     |                                |  25,751   |   |   |  (671) |   |   |  25,080 |   |
|                                                |                                |           |   |   |   |   |   |   |   |
| Basic      net income per share                     |                                |  $0.44    |   |   |  $(0.02) |   |   |  $0.42 |   |
| Diluted      net income per share                   |                                |  0.43     |   |   |  (0.02) | (1) |   |  0.41 | (1) |
|                                                |                                |           |   |   |   |   |   |   |   |
|                                                | Six      Months Ended June 30, 2008 |           |
|                                                | Previously      Reported            | Adjustment     | As      Adjusted |
| Interest      expense                               |                                |  $(2,143) |   |   |  $(2,178) |   |   |  $(4,321) |   |
| Income      from continuing operations before taxes |                                |  37,573   |   |   |  (2,178) |   |   |  35,395 |   |
| Income      tax provision                           |                                |  (14,058) |   |   |  836 |   |   |  (13,222) |   |
| Net      income                                     |                                |  39,433   |   |   |  (1,342) |   |   |  38,091 |   |
|                                                |                                |           |   |   |   |   |   |   |   |
| Basic      net income per share                     |                                |  $0.67    |   |   |  $(0.03) |   |   |  $0.64 |   |
| Diluted      net income per share                   |                                |  0.65     |   |   |  (0.03) | (1) |   |  0.62 | (1) |

|                                        | Previously      Reported | Adjustment | As      Adjusted |           |
|---------------------------------------------|--------------------------|------------|------------------|----------------|
| Non-current      deferred income taxes, net |  $73,851            |       |             | $10,645)       |   |  $63,206 |   |
| Other      non-current assets               |  5,033              |       |             |  (646)    |   |  4,387 |   |
| Total      assets                           |  865,186            |       |             |  (11,291) |   |  853,895 |   |
| Long-term      obligations                  |  143,750            |       |             |  (28,378) |   |  115,372 |   |
| Total      liabilities                      |  409,167            |       |             |  (28,378) |   |  380,789 |   |
| Additional      paid-in capital             |  525,027            |       |             |  22,362   |   |  547,389 |   |
| Accumulated      deficit                    |  (66,770)           |       |             |  (5,275)  |   |  (72,045) |   |
| Total      stockholders' equity             |  456,019            |       |             |  17,087   |   |  473,106 |   |

----

|   | • | Launch      Vehicles.  Rockets that are used as interceptor and      target vehicles for missile defense systems, small- and medium-class space      launch vehicles that place satellites into Earth orbit, and suborbital      launch vehicles that place payloads into a variety of high-altitude      trajectories. |
|--------|---------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | • | Satellites and Space      Systems.  Small- and medium-class spacecraft that are      used to enable global and regional communications and broadcasting, to      conduct space-related scientific research, to carry out interplanetary and      other deep-space exploration missions, to enable national security      applications, to collect imagery and other remotely-sensed data about the      Earth and to demonstrate new space  technologies. |
|--------|---------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | • | Advanced Space      Programs.  Human-rated space systems for Earth-orbit and      lunar exploration, advanced launch systems for medium-class satellites,      and small satellites and satellite subsystems primarily used for national      security space programs and to demonstrate new space      technologies. |
|--------|---------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

----

|                                  |   | Quarters      Ended June 30, |    |   | Six      Months Ended June 30, |   |
|---------------------------------------|--------|------------------------------|---------|--------|--------------------------------|--------|
|                                  |   | 2009                         |    |   | 2008                           |   |   | 2009 |   |   | 2008 |   |
| Launch      Vehicles:                 |   |                         |    |   |                           |   |   |   |   |   |   |   |
|   Revenues(1)               |   | $                            | 117,072 |   |                           | $      | 115,024 |   |   | $ | 236,312 |   |   | $ | 220,281 |   |
|   Operating      income     |   |                         | 4,082   |   |                           |   | 13,399 |   |   |   | 8,368 |   |   |   | 21,014 |   |
|   Identifiable      assets  |   |                         | 161,163 |   |                           |   | 127,609 | (2) |   |   | 161,163 |   |   |   | 127,609 | (2) |
|   Capital      expenditures |   |                         | 1,267   |   |                           |   | 955 |   |   |   | 2,727 |   |   |   | 4,957 |   |
|   Depreciation              |   |                         | 1,470   |   |                           |   | 1,340 |   |   |   | 3,081 |   |   |   | 2,627 |   |
| Satellites and Space      Systems:    |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
|   Revenues(1)               |   | $                            | 94,121  |   |                           | $      | 108,078 |   |   | $ | 204,278 |   |   | $ | 214,480 |   |
|   Operating      income     |   |                         | 7,734   |   |                           |   | 7,578 |   |   |   | 15,534 |   |   |   | 15,447 |   |
|   Identifiable      assets  |   |                         | 165,670 |   |                           |   | 164,119 | (2) |   |   | 165,670 |   |   |   | 164,119 | (2) |
|   Capital      expenditures |   |                         | 4,940   |   |                           |   | 3,213 |   |   |   | 8,464 |   |   |   | 5,069 |   |
|   Depreciation              |   |                         | 2,169   |   |                           |   | 2,222 |   |   |   | 4,345 |   |   |   | 4,363 |   |
| Advanced      Space Programs:         |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
|   Revenues                  |   | $                            | 62,053  |   |                           | $      | 79,719 |   |   | $ | 130,399 |   |   | $ | 152,328 |   |
|   Operating      income     |   |                         | 1,005   |   |                           |   | 5,730 |   |   |   | 83 |   |   |   | 10,572 |   |
|   Identifiable      assets  |   |                         | 103,936 |   |                           |   | 85,185 | (2) |   |   | 103,936 |   |   |   | 85,185 | (2) |
|   Capital      expenditures |   |                         | 5,171   |   |                           |   | — |   |   |   | 5,749 |   |   |   | — |   |
|   Depreciation              |   |                         | 3       |   |                           |   | 3 |   |   |   | 6 |   |   |   | 6 |   |
| Corporate      and Other:             |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
|   Revenues(1)               |   | $                            | (3,117  | )      |                           | $      | (1,598 | ) |   | $ | (5,119 | ) |   | $ | (2,321 | ) |
|   Operating      income     |   |                         | — |   |                           |   | (220 | )(3) |   |   | — |   |   |   | (555 | ) |
|   Identifiable      assets  |   |                         | 478,342 |   |                           |   | 476,982 | (2)(4) |   |   | 478,342 |   |   |   | 476,982 | (2)(4) |
|   Capital      expenditures |   |                         | 1,082   |   |                           |   | 951 | (3) |   |   | 1,417 |   |   |   | 1,829 | (3) |
|   Depreciation              |   |                         | 1,114   |   |                           |   | 1,056 | (3) |   |   | 2,200 |   |   |   | 2,160 | (3) |
| Consolidated:                         |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
|   Revenues                  |   | $                            | 270,129 |   |                           | $      | 301,223 |   |   | $ | 565,870 |   |   | $ | 584,768 |   |
|   Operating      income     |   |                         | 12,821  |   |                           |   | 26,487 |   |   |   | 23,985 |   |   |   | 46,478 |   |
|   Identifiable      assets  |   |                         | 909,111 |   |                           |   | 853,895 | (2)(4) |   |   | 909,111 |   |   |   | 853,895 | (2)(4) |
|   Capital      expenditures |   |                         | 12,460  |   |                           |   | 5,119 |   |   |   | 18,357 |   |   |   | 11,855 |   |
|   Depreciation              |   |                         | 4,756   |   |                           |   | 4,621 |   |   |   | 9,632 |   |   |   | 9,156 |   |

|   |  (1)  Corporate      and other revenues are comprised solely of the elimination of intersegment      sales.  Launch vehicles segment revenues include $2.5 million      and $0.3 million of intersegment sales in the quarters ended June 30, 2009      and 2008, respectively, and $3.3 million and $0.5 million of intersegment      sales in the six months ended June 30, 2009 and 2008,      respectively.  Satellites and space systems segment revenues      include $0.6 million and $1.2 million of intersegment sales in the      quarters ended June 30, 2009 and 2008, respectively, and $1.7 in the six      months ended June 30, 2009 and2008. |
|--------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | (2)  As      of December 31, 2008. |
|--------|----------------------------------------------|

|   | (3)  Includes      amounts attributable to a former business unit that was sold in the second      quarter of 2008. |
|--------|-------------------------------------------------------------------------------------------------------------------------------|

|   | (4)  As      adjusted (see Note 3). |
|--------|-----------------------------------------------|

----

|                                             |                                                           |   | Quarters      Ended June 30, |    |   | Six      Months Ended June 30, |   |
|--------------------------------------------------|----------------------------------------------------------------|--------|------------------------------|---------|--------|--------------------------------|--------|
| Numerator                                        |                                                           | 2009   |                         |    | 2008   |                           |   | 2009 |   |   | 2008 |   |
|                                             | Income      from continuing operations                         |   | $                            | 8,739   |   |                           | $      | 10,111 |   |   | $ | 17,941 |   |   | $ | 22,173 |   |
|                                             | Percentage      allocated to shareholders (1)                  |   |                         | 98.5    | %      |                           |   | 98.2 | % |   |   | 98.5 | % |   |   | 98.2 | % |
|                                             | Numerator      for basic and diluted earnings per share        |   | $                            | 8,608   |   |                           | $      | 9,929 |   |   | $ | 17,672 |   |   | $ | 21,774 |   |
|                                             |                                                           |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
| Denominator                                      |                                                           |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |
|                                             | Denominator      for basic earnings per share - weighted-      |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
|                                             |     average      shares outstanding        |   |                         | 56,450  |   |                           |   | 58,656 |   |   |   | 56,818 |   |   |   | 58,575 |   |
|                                             | Dilutive      effect of stock options                          |   |                         | 733     |   |                           |   | 1,240 |   |   |   | 748 |   |   |   | 1,279 |   |
|                                             | Dilutive      effect of convertible notes                      |   |                         | — |   |                           |   | 191 |   |   |   | — |   |   |   | — |   |
|                                             | Denominator      for diluted earnings per share                |   |                         | 57,183  |   |                           |   | 60,087 |   |   |   | 57,566 |   |   |   | 59,854 |   |
|                                             |                                                           |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
| Per      share income from continuing operations |                                                           |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |
|                                             | Basic                                                          |   | $                            | 0.15    |   |                           | $      | 0.17 |   |   | $ | 0.31 |   |   | $ | 0.37 |   |
|                                             | Diluted                                                        |   |                         | 0.15    |   |                           |   | 0.17 |   |   |   | 0.31 |   |   |   | 0.36 |   |
|                                             |                                                           |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
| _____________________________________            |                                                           |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |
|  (1)                                        | Basic      weighted-average shares outstanding                 |   |                         | 56,450  |   |                           |   | 58,656 |   |   |   | 56,818 |   |   |   | 58,575 |   |
|                                             | Basic      weighted-average shares outstanding and unvested    |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
|                                             |    restricted      share units expected to vest |   |                         | 57,326  |   |                           |   | 59,720 |   |   |   | 57,693 |   |   |   | 59,652 |   |
|                                             | Percentage      allocated to shareholders                      |   |                         | 98.5    | %      |                           |   | 98.2 | % |   |   | 98.5 | % |   |   | 98.2 | % |

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|                                |   | June      30, |    |   | December      31, |   |
|-------------------------------------|--------|---------------|---------|--------|-------------------|--------|
|                                |   | 2009          |    |   | 2008              |   |
| Billed                              |   | $             | 69,694  |   |              | $      | 51,156 |   |
| Unbilled                            |   |          | 148,046 |   |              |   | 151,955 |   |
|      Total |   | $             | 217,740 |   |              | $      | 203,111 |   |

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|                        | June      30, 2009 |                            | December      31, 2008       |
|-----------------------------|--------------------|---------------------------------|------------------------------|
| Cost      or Amortized Cost |               | Net      Unrealized Gain (Loss) |                         | Fair      Value |   | Cost      or Amortized Cost |   | Net      Unrealized Loss |   | Fair      Value |
| Debt                        |  $12,900      |                            |  $        200 |   |  $13,100 |   |  $12,900 |   |  $— |   |  $12,900 |
| Equity                      |  2,500        |                            |  (900)                  |   |  1,600 |   |  3,800 |   |  — |   |  3,800 |
| Total                       |  $15,400      |                            |  $(700)                 |   |  $14,700 |   |  $16,700 |   |  $— |   |  $16,700 |
|                        |               |                            |                         |   |   |   |   |   |   |   |   |

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|                                                  |   | Quarters      Ended June 30, |    |   | Six      Months Ended June 30, |   |
|-------------------------------------------------------|--------|------------------------------|---------|--------|--------------------------------|--------|
|                                                  |   | 2009                         |    |   | 2008                           |   |   | 2009 |   |   | 2008 |   |
| Debt      Securities                                  |   |                         |    |   |                           |   |   |   |   |   |   |   |
| Fair      value at beginning of period                |   | $                            | 12,800  |   |                           | $      | 17,600 |   |   | $ | 12,900 |   |   | $ | 17,700 |   |
| Temporary      impairment (charges) credits, net      |   |                         | 300     |   |                           |   | 1,100 |   |   |   | 200 |   |   |   | 1,000 |   |
| Other-than-temporary      impairment charges          |   |                         | — |   |                           |   | (1,400 | ) |   |   | — |   |   |   | (1,400 | ) |
|     Net      change in fair value |   |                         | 300     |   |                           |   | (300 | ) |   |   | 200 |   |   |   | (400 | ) |
| Fair      value at end of period                      |   | $                            | 13,100  |   |                           | $      | 17,300 |   |   | $ | 13,100 |   |   | $ | 17,300 |   |
|                                                  |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
|                                                  |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
| Equity      Securities                                |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
| Fair      value at beginning of period                |   | $                            | 1,900   |   |                           | $      | 7,900 |   |   | $ | 3,800 |   |   | $ | 10,300 |   |
| Temporary      impairment (charges) credits, net      |   |                         | 300     |   |                           |   | 6,600 |   |   |   | (900 | ) |   |   | 4,200 |   |
| Other-than-temporary      impairment charges          |   |                         | (600    | )      |                           |   | (9,200 | ) |   |   | (1,300 | ) |   |   | (9,200 | ) |
|     Net      change in fair value |   |                         | (300    | )      |                           |   | (2,600 | ) |   |   | (2,200 | ) |   |   | (5,000 | ) |
| Fair      value at end of period                      |   | $                            | 1,600   |   |                           | $      | 5,300 |   |   | $ | 1,600 |   |   | $ | 5,300 |   |
|                                                  |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
|                                                  |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
| Total                                                 |   |                         |    |   |                           |   |   |   |   |   |   |   |   |   |   |   |
| Fair      value at beginning of period                |   | $                            | 14,700  |   |                           | $      | 25,500 |   |   | $ | 16,700 |   |   | $ | 28,000 |   |
| Temporary      impairment (charges) credits, net      |   |                         | 600     |   |                           |   | 7,700 |   |   |   | (700 | ) |   |   | 5,200 |   |
| Other-than-temporary      impairment charges          |   |                         | (600    | )      |                           |   | (10,600 | ) |   |   | (1,300 | ) |   |   | (10,600 | ) |
|     Net      change in fair value |   |                         | — |   |                           |   | (2,900 | ) |   |   | (2,000 | ) |   |   | (5,400 | ) |
| Fair      value at end of period                      |   | $                            | 14,700  |   |                           | $      | 22,600 |   |   | $ | 14,700 |   |   | $ | 22,600 |   |

----

----

|                                                          |   | Quarter      Ended June 30, |   |   | Six      Months Ended June 30, |   |
|---------------------------------------------------------------|--------|-----------------------------|--------|--------|--------------------------------|--------|
|                                                          |   | 2009                        |   |   | 2008                           |   |   | 2009 |   |   | 2008 |   |
|                                                          |   |                        |   |   | (As      Adjusted)             |   |   |   |   |   | (As      Adjusted) |   |
| Net      income                                               |   | $                           | 8,739  |   |                           | $      | 25,080 |   |   | $ | 17,941 |   |   | $ | 38,091 |   |
| Temporary      investment impariment (charges) credits, net   |   |                        | 600    |   |                           |   | 7,700 |   |   |   | (700 | ) |   |   | 5,200 |   |
| Defined      benefit plans, net of tax                        |   |                        | 743    |   |                           |   | (377 | ) |   |   | 425 |   |   |   | (987 | ) |
|      Total      comprehensive income |   | $                           | 10,082 |   |                           | $      | 32,403 |   |   | $ | 17,666 |   |   | $ | 42,304 |   |

----

|                                  | Restricted      Stock Units     |                                              | Stock      Options |
|---------------------------------------|---------------------------------|---------------------------------------------------|--------------------|
|                                  |  Number      of Units | Weighted      Average Measurement Date Fair Value |               |  Number      of Options |   |  Weighted Average      Eercise Prce |
| Outstanding      at December 31, 2008 |  877,794                   |                                              |  $23.01       |   |   |  2,500,233 |   |   |  $9.01 |   |
|   Granted(1)                |  32,510                    |                                              |  17.90        |   |   |  — |   |   |  — |   |
|   Exercised                 |  —                   |                                              |  —      |   |   |  (48,901) |   |   |  8.99 |   |
|   Vested                    |  (21,446)                  |                                              |  23.19        |   |   |  — |   |   |  — |   |
|   Forfeited                 |  (10,845)                  |                                              |  21.94        |   |   |  (7,500) |   |   |  12.15 |   |
|   Expired                   |  —                   |                                              |  —      |   |   |  (80,800) |   |   |  28.00 |   |
| Outstanding      at June 30, 2009     |  878,013                   |                                              |  $22.83       |   |   |  2,363,032 | (2) |   |  $8.35 |   |

| (1)   | The      fair value of restricted stock unit grants is determined based on the      closing market price of Orbital’s common stock on the date of      grant.  Such value is recognized as expense over the service      period, net of estimatedforfeitures. |
|-----------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| (2)   | The      weighted average remaining contractual term is 3.04  years. |
|-----------------|----------------------------------------------------------------------|

|                                                                                               | Quarters      Ended June 30,   |
|----------------------------------------------------------------------------------------------------|--------------------------------|
| (in      millions)                                                                                 | 2009                           |   | 2008 |
| Stock-based      compensation expense                                                              |  $2.7                     |   |   | $1.9 |   |
| Income      tax benefit related to stock-based compensation expense                                |  0.9                      |   |   |  0.6 |   |
| Intrinsic      value of options exercised computed as the market                                   |                           |   |   |   |   |
|    price      on the exercise date less the price paid to exercise the      options |  0.1                      |   |   |  5.3 |   |
| Cash      received from exercise of options                                                        |  0.3                      |   |   |  4.0 |   |
| Tax      benefit recorded as credits to additional paid-in capital      related                    |                           |   |   |   |   |
|    to      stock-based compensation transactions                                    |  0.1                      |   |   |  1.7 |   |
|                                                                                               |                           |   |   |   |   |
|                                                                                               | Six      Months Ended June 30, |
| (in      millions)                                                                                 | 2009                           |   | 2008 |
| Stock-based      compensation expense                                                              |  $5.1                     |   |   | $4.0 |   |
| Income      tax benefit related to stock-based compensation expense                                |  1.7                      |   |   |  1.2 |   |
| Intrinsic      value of options exercised computed as the market                                   |                           |   |   |   |   |
|    price      on the exercise date less the price paid to exercise the      options |  0.3                      |   |   |  7.1 |   |
| Cash      received from exercise of options                                                        |  0.4                      |   |   |  5.4 |   |
| Tax      benefit recorded as credits to additional paid-in capital      related                    |                           |   |   |   |   |
|    to      stock-based compensation transactions                                    |  0.1                      |   |   |  2.4 |   |

|                                                                                                  | As      of         |
|-------------------------------------------------------------------------------------------------------|--------------------|
| (in      millions)                                                                                    | June      30, 2009 |
| Shares      of common stock available for grant under stock-based incentive      plans                |               |  1.5 |   |
| Aggregate      intrinsic value of restricted stock units that are expected to      vest               |               |  $13.3 |   |
| Unrecognized      compensation expense related to non-vested restricted stock units,      expected to |               |   |   |
|    be      recognized over a weighted-average period of 1.34 years                     |               |  10.1 |   |
| Aggregate      intrinsic value of stock options outstanding, all fully    vested                      |               |  16.2 |   |

----

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----

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| ·   | Launch      Vehicles.  Rockets that are used as interceptor and      target vehicles for missile defense systems, small- and medium-class space      launch vehicles that place satellites into Earth orbit, and suborbital      launch vehicles that place payloads into a variety of high-altitude      trajectories. |
|--------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| ·   | Satellites and Space      Systems.  Small- and medium-class spacecraft that are      used to enable global and regional communications and broadcasting, to      conduct space-related scientific research, to carry out interplanetary and      other deep-space exploration missions, to enable national security      applications, to collect imagery and other remotely-sensed data about the      Earth and demonstrate new spacetechnologies. |
|--------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

| ·   | Advanced Space      Programs.  Human-rated space systems for Earth-orbit and      lunar exploration, advanced launch systems for medium-class satellites,      and small satellites and satellite subsystems primarily used for national      security space programs and to demonstrate new space      technologies. |
|--------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

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|                                    |   | Second      Quarter |    |   | First      Six Months |   |
|-----------------------------------------|--------|---------------------|---------|--------|-----------------------|--------|
| (in      thousands, except percentages) |   | 2009                |    |   | 2008                  |   |   | %      Change |   |   | 2009 |   |   | 2008 |   |   | %      Change |   |
| Revenues                                |   | $                   | 117,072 |   |                  | $      | 115,024 |   |   |   | 2% |   |   | $ | 236,312 |   |   | $ | 220,281 |   |   |   | 7% |   |
| Operating      income                   |   |                | 4,082   |   |                  |   | 13,399 |   |   |   | (70%) |   |   |   | 8,368 |   |   |   | 21,014 |   |   |   | (60%) |   |
| Operating      margin                   |   |                | 3.5     | %      |                  |   | 11.6 | % |   |   |   |   |   |   | 3.5 | % |   |   | 9.5 | % |   |   |   |   |

----

|                                    |   | Second      Quarter |   |   | First      Six Months |   |
|-----------------------------------------|--------|---------------------|--------|--------|-----------------------|--------|
| (in      thousands, except percentages) |   | 2009                |   |   | 2008                  |   |   | %      Change |   |   | 2009 |   |   | 2008 |   |   | %      Change |   |
| Revenues                                |   | $                   | 94,121 |   |                  | $      | 108,078 |   |   |   | (13%) |   |   | $ | 204,278 |   |   | $ | 214,480 |   |   |   | (5%) |   |
| Operating      income                   |   |                | 7,734  |   |                  |   | 7,578 |   |   |   | 2% |   |   |   | 15,534 |   |   |   | 15,447 |   |   |   | 1% |   |
| Operating      margin                   |   |                | 8.2    | %      |                  |   | 7.0 | % |   |   |   |   |   |   | 7.6 | % |   |   | 7.2 | % |   |   |   |   |

----

|                                    |   | Second      Quarter |   |   | First      Six Months |   |
|-----------------------------------------|--------|---------------------|--------|--------|-----------------------|--------|
| (in      thousands, except percentages) |   | 2009                |   |   | 2008                  |   |   | %      Change |   |   | 2009 |   |   | 2008 |   |   | %      Change |   |
| Revenues                                |   | $                   | 62,053 |   |                  | $      | 79,719 |   |   |   | (22%) |   |   | $ | 130,399 |   |   | $ | 152,328 |   |   |   | (14%) |   |
| Operating      income                   |   |                | 1,005  |   |                  |   | 5,730 |   |   |   | (82%) |   |   |   | 83 |   |   |   | 10,572 |   |   |   | (99%) |   |
| Operating      margin                   |   |                | 1.6    | %      |                  |   | 7.2 | % |   |   |   |   |   |   | 0.1 | % |   |   | 6.9 | % |   |   |   |   |

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| ITEM      4.   CONTROLS ANDPROCEDURES |
|------------------------------------------------------|

----

| ITEM      2. | UNREGISTERED      SALES OF EQUITY SECURITIES AND USE OFPROCEEDS |
|--------------|-----------------------------------------------------------------|

| (a)   | None. |
|-----------------|-------|

| (b)   | None. |
|-----------------|-------|

----

|     Period                       |    Total      Number of Shares Purchased |     Average      Price Paid Per Share |   Total      Number of Shares Purchased as Part of Publicly Announced Plans or      Programs(1) | Maximum      Number (or Approximate Dollar Value) of Shares That May Yet Be Purchased      Under the Plans or Programs(1) |
|------------------------------------------------------|---------------------------------------------------------|-----------------------------------------------------------|-----------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------------------------------------|
| April      1, 2009  to April 30, 2009 | 162,600                                                 | $12.92                                                    | 162,600                                                                                                   | $45,635,237                                                                                                               |
|                                                 |                                                    |                                                      |                                                                                                      |                                                                                                                      |
| May      1, 2009 to May 31, 2009                | —                                                 | —                                                   | —                                                                                                   | 45,635,237                                                                                                                |
|                                                 |                                                    |                                                      |                                                                                                      |                                                                                                                      |
| June      1, 2009 to June 30, 2009              | —                                                 | —                                                   | —                                                                                                   | 45,635,237                                                                                                                |
|                                                 |                                                    |                                                      |                                                                                                      |                                                                                                                      |
| TOTAL                                                | 162,600                                                 | $12.92                                                    | 162,600                                                                                                   | $45,635,237                                                                                                               |

| (1)   | On      March 6, 2009, we announced a plan (“2009 Plan”), to repurchase up to $50      million of outstanding common stock through March 5, 2010, subject to      certain conditions.  During the quarter ended June 30, 2009, we      repurchased 162,600 shares under the 2009 Plan.  The purchases      were made in open markettransactions. |
|-----------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

|   | Not      applicable. |
|--------|----------------------|

----

| (a)   | The      annual meeting of stockholders of the Company was held on      April 30, 2009. |
|-----------------|---------------------------------------------------------------------------------------------------|

| (b)   | Election      of five directors, each serving for a three-year term ending in      2012: |
|-----------------|------------------------------------------------------------------------------------------|

----

| (c)   | The      following is a brief description of the other matter voted on at the      meeting and the number of votes cast for, against or abstaining from the      matter: |
|-----------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------|

----

----

| Exhibit      No. | Description                                                                                                                                                                                                                                                             |
|------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| 3.1              | Restated      Certificate of Incorporation (incorporated by reference to Exhibit 4.1 to      the company’s Registration Statement on Form S-3 (File Number 333-08769)      filed and effective on July 25, 1996).                                                 |
| 3.2              | Amended      and Restated Bylaws (incorporated by reference to Exhibit 3.2 to the      company’s Quarterly Report on Form 10-Q for the quarter ended June 30,      2005).                                                                                         |
| 3.3              | Certificate      of Amendment to Restated Certificate of Incorporation, dated April 29,      1997 (incorporated by reference to Exhibit 3.3 to the company’s Annual      Report on Form 10-K for the fiscal year ended December 31,      1998).                   |
| 3.4              | Certificate      of Amendment to Restated Certificate of Incorporation, dated April 30,      2003 (incorporated by reference to Exhibit 3.4 to the company’s Quarterly      Report on Form 10-Q for the quarter ended June 30,  2003).                                 |
|             |                                                                                                                                                                                                                                                                         |
| 4.1              | Form      of Certificate of Common Stock (incorporated by reference to Exhibit 4.1      to the company’s Registration Statement on Form S-1 (File Number 33-33453)      filed on February 9, 1990 and effective on April 24, 1990).                               |
| 4.2              | Indenture      dated as of December 13, 2006, by and between Orbital Sciences Corporation      and The Bank of New York, as Trustee (incorporated by reference to Exhibit      4.1 to the company’s Current Report on Form 8-K filed on December 13,      2006).  |
| 4.3              | Form      of 2.4375% Convertible Senior Subordinated Note due 2027 (incorporated by      reference to Exhibit 4.2 to the company’s Current Report on Form 8-K filed      on December 13, 2006).                                                                        |
|             |                                                                                                                                                                                                                                                                         |
| 31.1             | Certification      of Chairman and Chief Executive Officer pursuant to Section 302 of the      Sarbanes-Oxley Act of 2002 (18 U.S.C. Section 1350) (transmitted      herewith).                                                                                         |
| 31.2             | Certification      of Vice Chairman and Chief Financial Officer pursuant to Section 302 of      the Sarbanes-Oxley Act of 2002 (18 U.S.C. Section 1350) (transmitted      herewith).                                                                                    |
| 32.1             | Written      Statement of Chairman and Chief Executive Officerpursuant      to Section 906 of the Sarbanes-Oxley Act of 2002 (18 U.S.C. Section 1350)      (transmitted herewith).                                                                                      |
| 32.2             | Written      Statement of Vice Chairman and Chief Financial Officerpursuant      to Section 906 of the Sarbanes-Oxley Act of 2002 (18 U.S.C. Section 1350)      (transmitted herewith).                                                                                 |

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