STS-41-B was NASA's tenth Space Shuttle mission and the fourth flight of the . It launched on February 3, 1984 and landed on February 11, 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. Because the original successor to STS-9, STS-10, was canceled due to payload delays, the next flight, originally and internally designated STS-11, became STS-41-B as part of the new numbering system.
Crew
Spacewalks
;EVA 1
- Personnel: McCandless and Stewart
- Date: February 7, 1984
- Duration: 5 hours, 55 minutes
! Launch
! Landing
|rowspan=8| 150px<br />Seats 1–4 are on the flight deck.<br />Seats 5–7 are on the mid-deck.
|-
! 1
|colspan=2| Brand
|-
! 2
|colspan=2| Gibson
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! 3
| McNair
| McCandless
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! 4
|colspan=2| Stewart
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! 5
| McCandless
| McNair
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! 6
|colspan=2 style="background-color:lightgray"| Unused
|-
! 7
|colspan=2 style="background-color:lightgray"| Unused
|}
Mission summary
thumb|upright=1.0|right|STS-41B launch
thumb|upright=1.0|right|Palapa B2 after deployment
thumb|upright=1.0|right|Astronaut Bruce McCandless exercises the [[Manned Maneuvering Unit.]]
thumb|upright=1.0|right|McCandless approaches his maximum distance from Challenger.
Crew
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.
Launch and satellite deployment
Challenger lifted off from Kennedy Space Center at 08:00:00 a.m. EST on February 3, 1984. It was estimated that 100,000 people attended the launch. 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; 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. At 8:25 a.m. EST, pulsing the MMU's thrusters, McCandless ventured out of Challengers payload bay, and reached from the orbiter. Stewart tested the "work station" foot restraint at the end of the Remote Manipulator System (Canadarm). 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. but the damage was minimal enough that Challenger and its crew were unharmed.
{| class="wikitable"
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! Flight day
! Song
! Artist/composer
! Played for
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| Day 2
| Garbled during the broadcast, title unknown
| Contraband