STS-121

space shuttle mission

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July 22, 2026

Quick Summary

STS-121 was a space shuttle mission that launched on July 4, 2006, using the orbiter Discovery. The mission's primary goal was to test new equipment and procedures for shuttle safety and to deliver supplies and crew members to the International Space Station (ISS). This mission was significant as it was the second flight after the Columbia disaster in 2003, and it aimed to demonstrate the shuttle's readiness for continued operations. The crew conducted several spacewalks to test repair techniques and assess the shuttle's thermal protection system. STS-121 successfully increased the ISS crew size from two to three, contributing to the ongoing assembly and research aboard the station.12

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Mark Kelly
Life in space
…July 2006 on the 13-day STS-121 mission as pilot of the space shuttle Discovery. He also made two flights to the ISS as mission commander.
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…July 2006 on the 13-day STS-121 mission as pilot of the space shuttle Discovery. He also made two flights to the ISS as mission commander.
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Stephanie Wilson
Wilson’s first spaceflight was the STS-121 mission of the space shuttle Discovery, which launched on July 4, 2006, to the ISS. STS-121 was the second flight after the Columbia disaster, and thus a key aim of the mission was testing safety procedures that would detect shuttle orbiter damage like that…
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Wilson’s first spaceflight was the STS-121 mission of the space shuttle Discovery, which launched on July 4, 2006, to the ISS. STS-121 was the second flight after the Columbia disaster, and thus a key aim of the mission was testing safety procedures that would detect shuttle orbiter damage like that…
Read More