STS-121

The second space shuttle flight since the loss of Columbia is scheduled for July 1. Shuttle missions have been delayed nearly a year to allow for design changes to the shuttle's external fuel tank insulation system. Falling foam debris from the external fuel tank damaged the Columbia orbiter and resulted in the breakup of the vehicle during re-entry in 2003. Following initial design changes, foam debris was still a persistent problem during the first launch of the shuttle since Columbia in July 2005. Additional design changes bring us up to date, with the launch of shuttle Discovery on mission STS-121 July 1. During this mission, the shuttle will dock with the International Space Station and test some of the new safety measures that have been put in place since the Columbia accident. For one, the exterior of the shuttle will be inspected for launch damage using a new laser detection system shortly before re-entry.

From left to right are Michael Fossum, Thomas Reiter, Mark Kelley, Steven Lindsey, Lisa Nowak, Stephanie Wilson, and Piers Sellers.