| Name of Satellite, Alternate Names | Milstar DFS-4 (USA 157, Milstar 2-F2) (Military Strategic and Tactical Relay) |
| Country of Operator/Owner | USA |
| Operator/Owner | US Air Force |
| Users | Military |
| Purpose | Communications |
| Class of Orbit | GEO |
| Type of Orbit | |
| Longitude of GEO (degrees) | -67.9 |
| Perigee (km) | 35764 |
| Apogee (km) | 35768 |
| Eccentricity | 4.74653502942852E-05 |
| Inclination (degrees) | 4.5 |
| Period (minutes) | 1435.04 |
| Launch Mass (kg.) | 4536 |
| Dry Mass (kg.) | |
| Power (watts) | 8000 |
| Date of Launch | 27-02-2001 |
| Expected Lifetime | 12 yrs. |
| Contractor | Lockheed Martin Missiles and Space |
| Country of Contractor | USA |
| Launch Site | Cape Canaveral |
| Launch Vehicle | Titan 4B |
| COSPAR Number | 2001-009A |
| NORAD Number | 26715 |
| Comments | Voice communication, data, imagery and video; survivable global military communication system. "World´s most secure, nuclear survivable, space-based communication system." |