Spacecraft information: ESIAFI 1
| Launched | 20 February 1981 |
| Flight ended | – |
| Status | Non-operational |
| Launch site | Air Force Eastern Test Range, Florida, USA |
| Owner | United States |
| NORAD ID | 12309 |
| COSPAR ID | 1981-018A |
| Alternative names |
COMSTAR 4 |
| Observing |
Current orbital elements
| Inclination | 8.669° |
| Eccentricity | 0.00030 |
| RA ascending node | 20.741 hr |
| Argument perigee | 92.443° |
| Mean anomaly | 267.708° |
| Orbital period | 1436.061 min |
| Epoch of osculation | 04 Jul 2026, 21:15 |
Derived Quantities
| Min Altitude | 35780.3 km |
| Mean Altitude | 35793.0 km |
| Peak Altitude | 35805.8 km |
Launched alongside
ATLAS CENTAUR R/BOrbital History
Drag the graphs below left or right to change the time range, or use your scroll wheel to zoom in or out.