STS-121 was a space shuttle mission that launched on July 12, 2006. It was part of NASA's Space Shuttle program and aimed to deliver supplies and equipment to the International Space Station (ISS). The mission was significant as it tested new safety measures following the Columbia disaster in 2003. The shuttle Discovery carried a crew of seven astronauts, including Eileen Collins, the first female commander of a shuttle mission. During the 13-day mission, the crew conducted various experiments and performed a spacewalk to inspect the shuttle's thermal protection system. The mission successfully concluded with a landing on July 26, 2006.