Which space shuttle conducted the first spacewalk from a shuttle?

The space shuttle that conducted the first spacewalk from a shuttle was Challenger. Its first mission, STS-6, launched on April 4, 1983, and marked the Space Shuttle program’s first extravehicular activity (EVA).

Astronauts Story Musgrave and Donald Peterson performed the spacewalk on April 7–8, testing new shuttle spacesuits and working in Challenger’s payload bay. The EVA lasted 4 hours and 17 minutes, making it the first American spacewalk since the final Skylab 4 EVA nearly a decade earlier.

This milestone is sometimes confused with the first spacewalk ever. That occurred in 1965, when Soviet cosmonaut Alexei Leonov left Voskhod 2. The first American spacewalk was performed by Ed White during Gemini 4 in 1965. Challenger’s achievement was specifically the first EVA carried out as part of the Space Shuttle program.

STS-6 also introduced other shuttle innovations, including a lightweight external tank, lightweight solid rocket booster casings, and the shuttle’s first head-up display. Challenger later flew nine missions before being lost during the launch of STS-51-L in 1986.