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 DSCS-III satellites in Atlantis' payload bay | |
| Names | Space Transportation System-21 |
|---|---|
| Mission type | Satellite deployment |
| Operator | NASA / U.S. DoD |
| COSPAR ID | 1985-092A |
| SATCAT no. | 16115 |
| Mission duration | 4 days, 1 hour, 44 minutes and 38 seconds |
| Distance travelled | 2,707,948 km (1,682,641 mi) |
| Orbits completed | 64 |
| Spacecraft properties | |
| Spacecraft | Space Shuttle Atlantis |
| Launch mass | N/A |
| Landing mass | 86,400 kg (190,500 lb) |
| Payload mass | 19,968 kg (44,022 lb) |
| Crew | |
| Crew size | 5 |
| Members | |
| Start of mission | |
| Launch date | October 3, 1985, 15:15:30 UTC (11:15:30 am EDT) |
| Launch site | Kennedy, LC-39A |
| Contractor | Rockwell International |
| End of mission | |
| Landing date | October 7, 1985, 17:00:08 UTC (10:00:08 am PDT) |
| Landing site | Edwards, Runway 23 |
| Orbital parameters | |
| Reference system | Geocentric orbit |
| Regime | Low Earth orbit |
| Perigee altitude | 475 km (295 mi) |
| Apogee altitude | 484 km (301 mi) |
| Inclination | 28.50° |
| Period | 94.20 minutes |
 STS-51-J mission patch  From left: Stewart, Hilmers, Bobko, Pailes and Grabe | |
STS-51-J was NASA's 21st Space Shuttle mission and the maiden flight of Space Shuttle Atlantis. It launched from Kennedy Space Center, Florida, on October 3, 1985, carrying a payload for the U.S. Department of Defense (DoD), and landed at Edwards Air Force Base, California, on October 7, 1985.