DSCS-III satellites in Atlantis' payload bay
NamesSpace Transportation System-21
Mission typeSatellite deployment
OperatorNASA / U.S. DoD
COSPAR ID1985-092A Edit this at Wikidata
SATCAT no.16115
Mission duration4 days, 1 hour, 44 minutes, 38 seconds (achieved)
Distance travelled2,707,948 km (1,682,641 mi)
Orbits completed64
Spacecraft properties
SpacecraftSpace Shuttle Atlantis
Launch massN/A
Landing mass86,400 kg (190,500 lb)
Payload mass19,968 kg (44,022 lb)
Crew size5
Start of mission
Launch dateOctober 3, 1985, 15:15:30 UTC
RocketSpace Shuttle Atlantis
Launch siteKennedy Space Center, LC-39A
ContractorRockwell International
End of mission
Landing dateOctober 7, 1985, 17:00:08 UTC
Landing siteEdwards Air Force Base,
Runway 23
Orbital parameters
Reference systemGeocentric orbit
RegimeLow Earth orbit
Perigee altitude475 km (295 mi)
Apogee altitude484 km (301 mi)
Period94.20 minutes

STS-51-J mission patch

Back row: David C. Hilmers, William A. Pailes
Seated: Robert L. Stewart, Karol J. Bobko, Ronald J. Grabe
← STS-51-I (20)
STS-61-A (22) →

STS-51-J was NASA's 21st Space Shuttle mission and the first 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.


Position Astronaut
Commander Karol J. Bobko
Third and last spaceflight
Pilot Ronald J. Grabe
First spaceflight
Mission Specialist 1 David C. Hilmers
First spaceflight
Mission Specialist 2 Robert L. Stewart
Second and last spaceflight
Payload Specialist 1 William A. Pailes, MSE
Only spaceflight

Backup crew

Position Astronaut
Payload Specialist 1 Michael W. Booen, MSE
First spaceflight

Crew notes

All five astronauts on the secret mission were active-duty military officers.[1] Before William A. Pailes was assigned to the STS-51-J flight, Mike Mullane was rumored to have been assigned as mission specialist 3 on his second trip to space.

Mission summary

STS-51-J launched on October 3, 1985, at 15:15:30 UTC (11:15:30 a.m. EDT), from Launch Pad 39A at the Kennedy Space Center. The launch was delayed by 22 minutes and 30 seconds due to a problem with a main engine liquid hydrogen prevalve close remote power controller; the controller was showing a faulty "on" indication.

The mission was the second shuttle flight totally dedicated to deploying a United States Department of Defense payload,[1] after STS-51-C. Its cargo was classified, but it was reported that two (USA-11 and USA-12) DSCS-III (Defense Satellite Communications System) satellites were launched into geostationary orbits by an Inertial Upper Stage (IUS). The DSCS satellites used X-band frequencies (8/7 GHz). Each DSCS-III satellite had a design life of ten years, although several of the DSCS satellites have far exceeded their design life expectancy.[2]

The mission was deemed successful. After a flight lasting 4 days, 1 hour, 44 minutes and 38 seconds, Atlantis landed on Runway 23 at Edwards Air Force Base at 17:00:08 UTC (13:00:08 EDT) on October 7, 1985. During STS-51-J, mission commander Bobko became the first astronaut to fly on three different shuttle orbiters, and the only astronaut to fly on the maiden voyages of two different orbiters.

Attempt Planned Result Turnaround Reason Decision point Weather go (%) Notes
1 3 Oct 1985, 2:53:00 pm delayed technical faulty indication from main engine liquid hydrogen prevalve close remote power controller
2 3 Oct 1985, 3:15:30 pm success 0 days, 0 hours, 23 minutes

Mission insignia

The 51-J mission insignia, designed by Atlantis's first crew, pays tribute to the Statue of Liberty and the ideas it symbolizes, but also as not to emphasize the "classified" nature of the mission like the first one did. The historical gateway figure bears additional significance for astronauts Karol J. Bobko, mission commander; and Ronald J. Grabe, pilot, both New York City natives.


See also


  1. ^ a b Blakeslee, Sandra (October 8, 1985). "ASTRONAUTS RETURN FROM SECRET [sic]". The New York Times. p. C3. ISSN 0362-4331. Retrieved June 18, 2021.
  2. ^ Day, Dwayne (January 4, 2010). "A lighter shade of black: the (non) mystery of STS-51J". The Space Review. Retrieved February 5, 2022.