Overmyer, Lind, Van den Berg, and Thornton in Spacelab Module LM1 during flight | |
| Names | Space Transportation System-17 Spacelab 3 |
|---|---|
| Mission type | Microgravity research |
| Operator | NASA |
| COSPAR ID | 1985-034A |
| SATCATno. | 15665 |
| Mission duration | 7 days, 8 minutes, 46 seconds |
| Distance travelled | 4,651,621 km (2,890,383 mi) |
| Orbits completed | 111 |
| Spacecraft properties | |
| Spacecraft | Space Shuttle Challenger |
| Launch mass | 111,980 kg (246,870 lb) |
| Landing mass | 96,373 kg (212,466 lb) |
| Payload mass | 15,610 kg (34,410 lb) |
| Crew | |
| Crew size | 7 |
| Members | |
| Start of mission | |
| Launch date | April 29, 1985, 16:02:18 (1985-04-29UTC16:02:18Z) UTC (12:02:18 pm EDT) |
| Launch site | Kennedy,LC-39A |
| Contractor | Rockwell International |
| End of mission | |
| Landing date | May 6, 1985, 16:11:04 (1985-05-06UTC16:11:05Z) UTC (9:11:04 am PDT) |
| Landing site | Edwards, Runway 17 |
| Orbital parameters | |
| Reference system | Geocentric orbit |
| Regime | Low Earth orbit |
| Perigee altitude | 346 km (215 mi) |
| Apogee altitude | 352 km (219 mi) |
| Inclination | 57.00° |
| Period | 91.50 minutes |
STS 51-B mission patch Standing:Lind,Wang,Thagard,Thornton andVan den Berg Sitting:Overmyer andGregory | |

STS-51-B was the 17th flight of theNASASpace Shuttle program and the seventh flight ofSpace ShuttleChallenger. The launch ofChallenger on April 29, 1985, was delayed by 2 minutes and 18 seconds, due to a launch processing failure.Challenger was initially rolled out to the pad to launch on theSTS-51-E mission. The shuttle was rolled back when a timing issue emerged with theTDRS-B satellite. When STS-51-E was canceled,Challenger was remanifested with the STS-51-B payloads. The shuttle landed successfully on May 6, 1985, after a week-long mission.
| Position | Astronaut | |
|---|---|---|
| Commander | Robert F. Overmyer Second and last spaceflight | |
| Pilot | Frederick D. Gregory First spaceflight | |
| Mission Specialist 1 | Don L. Lind Only spaceflight | |
| Mission Specialist 2 Flight Engineer | Norman E. Thagard Second spaceflight | |
| Mission Specialist 3 | William E. Thornton Second and last spaceflight | |
| Payload Specialist 1 | Lodewijk van den Berg Only spaceflight EG&G | |
| Payload Specialist 2 | Taylor G. Wang Only spaceflight Jet Propulsion Laboratory | |
| Position | Astronaut | |
|---|---|---|
| Payload Specialist 1 | Mary Helen Johnston | |
| Payload Specialist 2 | Eugene H. Trinh | |
| Seat[1] | Launch | Landing | Seats 1–4 are on the flight deck. Seats 5–7 are on the mid-deck. |
|---|---|---|---|
| 1 | Overmyer | ||
| 2 | Gregory | ||
| 3 | Lind | ||
| 4 | Thagard | ||
| 5 | Thornton | ||
| 6 | van den Berg | ||
| 7 | Wang | ||
The mission insignia features theChallenger with her payload doors open, to show the onboardSpacelab 3. The orbiter rides over the American flag. The seven crewmembers are represented by the 7 stars on the patch, that indirectly refer to theMercury Seven as a nod to their legacy. Behind the orbiter, the contours ofPegasus can be seen, as a reference to theEuropean Space Agency (ESA). The white board surrounding it all has the appearance of a space suit helmet, with the names of the two respective teams grouped around them on a round band encircling the insignia, and the two mission specialists on an added section below. To further create some sort of contrast, the team colors are reprised for each member's name.

Challenger lifted off fromKennedy Space Center (KSC)'s launch pad 39A at 12:02:18 p.m.EDT on April 29, 1985. The crew members includedRobert F. Overmyer, commander;Frederick D. Gregory, pilot;Don L. Lind,Norman E. Thagard andWilliam E. Thornton, mission specialists; andLodewijk van den Berg, ofEG&G Energy Management, Inc., andTaylor G. Wang, of theJet Propulsion Laboratory (JPL), both payload specialists.[2] Average age of 48.6 was the oldest for an American space mission.[3] Similar to theprevious Spacelab mission (STS-9), the crew was divided roughly in half to cover 12-hour shifts, with Overmyer, Lind, Thornton and Wang forming the Gold team, and Gregory, Thagard and Van den Berg as the Silver team.
STS-51-B was the second flight of theEuropean Space Agency (ESA)'sSpacelab pressurized module, and the first with the Spacelab module in a fully operational configuration. Spacelab's capabilities for multi-disciplinary research inmicrogravity were successfully demonstrated. The gravity gradient attitude of the orbiter proved quite stable, allowing the delicate experiments in materials processing and fluid mechanics to proceed normally. The crew operated around the clock in two 12-hour shifts. Twosquirrel monkeys and 24rats were flown in special cages,[4] the second time American astronauts flew live non-humanmammals aboard the shuttle. The crew members in orbit were supported 24 hours a day by a temporary Payload Operations Control Center, located at theJohnson Space Center.
An experiment designed by Taylor Wang malfunctioned upon activation. Wang, feeling immense pressure, received permission to attempt a fix and was successful in repairing the experiment, though remarks made by him caused concern for the safety of the crew and the mission.[5] The incident was covered in anArs Technica article on 22 January 2024. There,John Fabian, mission specialist onSTS-51-G, the very next shuttle flight after 51-B, was cited to explain why a lock was recently installed on the door of the side hatch: "It was installed when we got into orbit so that the door could not be opened from the inside and commithara-kiri, kill the whole crew. That was not because of anybody we had on our flight but because of a concern about someone who had flown before 51-G."[5]
On the mission, Spacelab carried 15 primary experiments, of which 14 were successfully performed. TwoGetaway Special (GAS) experiments required that they be deployed from their canisters, a first for the program. These were NUSAT (Northern Utah Satellite) and GLOMR (Global Low Orbiting Message Relay satellite). NUSAT deployed successfully, but GLOMR did not deploy, and was returned toEarth.
A Cosmic Ray Experiment byIndian Space Research Organisation, named Anuradha was launched onboard the mission. It measured the ionization states of low energy cosmic rays in near-earth space. It consisted of a Barrel shaped recorder consisting of plastic sheets. It detected cosmic rays at the rate of seven a minute for 64 hours and produced 10000 sheets of data
Challenger landed safely atEdwards Air Force Base at 12:11:04 p.m. EDT on May 6, 1985, after a mission lasting 7 days, 8 minutes, and 46 seconds.
While participating in the investigation into thedestruction ofChallenger during STS-51L in 1986, Overmyer discovered that a problem with the shuttle'sO-rings, similar to that which led to the disaster, had emerged during the launch of STS-51B.Morton-Thiokol engineers told Lind after the mission that "you came within three-tenths of one second of dying".[6] It was the problem with the O-rings on the leftsolid rocket motor (SRM) on this launch (SRM-16A) that promptedRoger Boisjoly to write a memo toBob Lund about the potential for the O-rings to cause catastrophic failure.[7]