| Official name | OPS 8781 |
| Alternative name | NOSS 2 MSD (OPS 8781) + Star-20 |
| Cospar ID | 1977-112A |
| Norad ID | 10502 |
| Launch date | 1977-12-08 |
| Launch site | AFWTR |
| Launch vehicle | Atlas-F MSD |
| Country/Organization | USA |
| Type application | Ocean Surveillance Launch Dispenser |
| Operator | ? |
| RCS size | UNKNOWN |
| Decay date | ON ORBIT |
| Period (min) | 102.71 |
| Inclination (deg) | 63.32 |
| Perigee (km) | 468 |
| Apogee (km) | 1306 |
| Eccentricity | 0.472378804960541 |
| Mean motion (revs. per day) | 14.0200564696719 |
| Semi-Major axis (km) | 7265.135 |
| Raan (deg) | 142.639 |
| Arg of perigee (deg) | 150.0869 |
| Shape | Cyl |
| Mass (kg) | 63.43 |
| Diameter (m) | 1.5 |
| Height (m) | 1.6 |
| Span (m^2) | 1.6 |
| Contractors | Naval Research Laboratory (NRL) (#1, 2); ? (#3 - 9) |
| Equipment | ? |
| Propulsion | FW-4D ? |
| Configuration | ? |
| Satellite | COSPAR | Date | LS | Launch Vehicle | Remarks | |
|---|---|---|---|---|---|---|
| OPS 6431 | 1976-038A | 1976-04-30 | AFWTR | Atlas-F MSD | with Parcae 1A, Parcae 1B, Parcae 1C | |
| OPS 8781 | 1977-112A | 1977-12-08 | AFWTR | Atlas-F MSD | with Parcae 2A, Parcae 2B, Parcae 2C | |
| OPS 7245 | 1980-019A | 1980-03-03 | AFWTR | Atlas-F MSD | with Parcae 3A, Parcae 3B, Parcae 3C | |
| OPS 0252 | 1983-008A | 1983-02-09 | AFWTR | Atlas-H MSD | with Parcae 5A, Parcae 5B, Parcae 5C, LIPS 2 | |
| OPS 6432 | 1983-056A | 1983-06-09 | AFWTR | Atlas-H MSD | with Parcae 6A, Parcae 6B, Parcae 6C | |
| OPS 8737 | 1984-012A | 1984-02-05 | AFWTR | Atlas-H MSD | with Parcae 7A, Parcae 7B, Parcae 7C | |
| USA 15 | 1986-014A | 1986-02-09 | AFWTR | Atlas-H MSD | with Parcae 8A, Parcae 8B, Parcae 8C | |
| USA 22 | 1987-043A | 1987-05-15 | AFWTR | Atlas-H MSD | with Parcae 9A, Parcae 9B, Parcae 9C, LIPS 3 |
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