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STS-51-J
	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	Karol J. Bobko; Ronald J. Grabe; David C. Hilmers; Robert L. Stewart; William A. Pailes;
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 Space Shuttle program ← STS-51-I (20) STS-61-A (22) →

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.

Crew


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 Flight Engineer	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

Crew seat assignments

Seat^[1]	Launch	Landing	Seats 1–4 are on the flight deck. Seats 5–7 are on the mid-deck.
1	Bobko
2	Grabe
3	Hilmers
4	Stewart
5	Pailes
6	Unused
7	Unused

Crew notes

All five astronauts on the secret mission were active-duty military officers.^[2] 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,^[2] 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.^[3]

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, 11:15:30 am	Success	—	Technical			Delayed due to faulty indication from main engine liquid hydrogen prevalve close remote power controller.

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.

Gallery

Atlantis lifting off the pad.

References

^ "STS-51J". Spacefacts. Retrieved July 29, 2024.
^ ^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.
^ Day, Dwayne (January 4, 2010). "A lighter shade of black: the (non) mystery of STS-51J". The Space Review. Retrieved February 5, 2022.