STS-41-B

Bruce McCandless II demonstrates the Manned Maneuvering Unit (MMU), floating in space above a clouded Earth.
Names	Space Transportation System-10
Mission type	Communications satellites deployment Equipment testing
Operator	NASA
COSPAR ID	1984-011A
SATCAT no.	14681
Mission duration	7 days, 23 hours, 15 minutes, 55 seconds (achieved)
Distance travelled	5,329,150 km (3,311,380 mi)
Orbits completed	128
Spacecraft properties
Spacecraft	Space Shuttle Challenger
Launch mass	113,603 kg (250,452 lb)
Landing mass	91,280 kg (201,240 lb)
Payload mass	12,815 kg (28,252 lb)[1]
Crew
Crew size	5
Members	Vance D. Brand Robert L. Gibson Bruce McCandless II Robert L. Stewart Ronald E. McNair
EVAs	2
EVA duration	12 hours, 12 minutes First: 5 hours, 55 minutes Second: 6 hours, 17 minutes
Start of mission
Launch date	3 February 1984, 13:00:00 UTC
Rocket	Space Shuttle Challenger
Launch site	Kennedy Space Center, LC-39A
Contractor	Rockwell International
End of mission
Landing date	11 February 1984, 12:15:55 UTC
Landing site	Kennedy Space Center, Runway 15
Orbital parameters
Reference system	Geocentric orbit[2]
Regime	Low Earth orbit
Perigee altitude	307 km (191 mi)
Apogee altitude	317 km (197 mi)
Inclination	28.50°
Period	90.80 minutes
Instruments
Get Away Special (GAS) canisters
STS-41-B mission patch Standing: Mission Specialists Robert L. Stewart, Ronald McNair and Bruce McCandless II. Stewart and McCandless are wearing Extravehicular Mobility Units (EMUs). Seated: Vance D. Brand and Robert L. Gibson Space Shuttle program ← STS-9 STS-41-C (11) →

STS-41-B was the tenth NASA Space Shuttle mission and the fourth flight of the Space Shuttle Challenger. It launched on 3 February 1984, and landed on 11 February 1984 after deploying two communications satellites. It was also notable for including the first untethered spacewalk.

Following STS-9, the flight numbering system for the Space Shuttle program was changed. Thus, the next flight, instead of being designated STS-10, became STS-41-B; the original successor to STS-9, STS-10, was canceled due to payload delays.

Crew

Spacewalks

EVA 1

• Personnel: McCandless and Stewart
• Date: 7 February 1984
• Duration: 5 hours, 55 minutes^[3]

EVA 2

• Personnel: McCandless and Stewart
• Date: 9 February 1984
• Duration: 6 hours, 17 minutes^[3]

Crew seating arrangements

Seat[4]	Launch	Landing	Seats 1–4 are on the Flight Deck. Seats 5–7 are on the Middeck.
S1	Brand	Brand
S2	Gibson	Gibson
S3	McNair	McCandless
S4	Stewart	Stewart
S5	McCandless	McNair

Mission summary

STS-41B launch

Palapa B2 after deployment

Astronaut Bruce McCandless exercises the Manned Maneuvering Unit.

McCandless approaches his maximum distance from Challenger.

Challenger lifted off from Kennedy Space Center at 08:00:00 a.m. EST on 3 February 1984. It was estimated that 100,000 people attended the launch.^[5] Two communications satellites were deployed about 8 hours after launch; one, Westar 6, was for America's Western Union, and the other, Palapa B2, for Indonesia;^[6] both were Hughes-built HS-376-series satellites. However, the Payload Assist Modules (PAM) for both satellites malfunctioned, placing them into a lower-than-planned orbit. Both satellites were retrieved successfully in November 1984 during STS-51-A, which was conducted by the orbiter Discovery.^[6]

The STS-41-B crew included commander Vance D. Brand, making his second Shuttle flight; pilot Robert L. Gibson; and mission specialists Bruce McCandless II, Ronald E. McNair, and Robert L. Stewart.

On the fourth day of the mission, astronauts McCandless and Stewart performed the first untethered spacewalk, operating the Manned Maneuvering Unit (MMU) for the first time.^[3][7] McCandless ventured out 98 m (322 ft) from the orbiter, while Stewart tested the "work station" foot restraint at the end of the Remote Manipulator System (Canadarm). On the seventh day of the mission, both astronauts performed another extravehicular activity (EVA) to practice capture procedures for the Solar Maximum Mission (SMM) satellite retrieval and repair operation, which was planned for the next mission, STS-41-C.^[3]

STS-41-B also achieved the reflight of the West German-sponsored SPAS-1 pallet/satellite, which had originally flown on STS-7.^[8] This time, however, it remained in the payload bay due to an electrical problem in the RMS (Canadarm). The mission also carried five Get Away Special (GAS) canisters, six live rats in the middeck area, a Cinema-360 camera and a continuation of the Continuous Flow Electrophoresis System and Monodisperse Latex Reactor experiments.^[8] Included in one of the GAS canisters was the first experiment designed and built by a high school team to fly in space. The experiment, on seed germination and growth in zero gravity, was created and built by a team of four students from Brighton High School in Utah through a partnership with Utah State University.^[8]

Brighton High School STS-11 Decal

The 7 days, 23 hours, 15 minutes, and 55 seconds flight ended on 11 February 1984 with a successful landing at Kennedy Space Center's Shuttle Landing Facility. This marked the first landing of a spacecraft at its launch site. Challenger completed 128 orbits and traveled 5,329,150 km (3,311,380 mi).

Mission insignia

Designed by artist Robert McCall, the eleven stars in the blue field symbolize the mission's original designation as STS-11. The left panel shows the deployment of a satellite, and the right panel shows an astronaut using the MMU.

Wake-up calls

NASA began a tradition of playing music to astronauts during the Project Gemini, and first used music to wake up a flight crew during Apollo 15. Each track is specially chosen, often by the astronauts' families, and usually has a special meaning to an individual member of the crew, or is applicable to their daily activities.^[9]

After the mission

Astronaut Bruce McCandless II sued singer Dido in 2010 over the use of a public domain photo of him in space on this mission on her 2008 album Safe Trip Home.^[10]

Two years after this mission, Ronald E. McNair was a crew member of the ill-fated STS-51-L. He and his six colleagues were killed when Challenger disintegrated 14 km (8.7 mi) above the Atlantic Ocean 73 seconds after liftoff.^[11]