The astronauts put and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A.

In the Operations and Checkout Building (O&C) at NASA's Kennedy Space Center in Florida, the astronauts of space shuttle Discovery's STS-133 crew put on their launch-and-entry suits and check the fit of their helmets and gloves before heading to the Astrovan for the ride to Launch Pad 39A. Mission Specialist Michael Barratt, seen here, is making his first flight aboard a space shuttle. Barratt has called the space station home before, though, after spending 199 days as a crew member of Expeditions 19 and 20 in 2009.

Scheduled to lift off Feb. 24 at 4:50 p.m. EST, Discovery and its crew will deliver the Permanent Multipurpose Module, packed with supplies and critical spare parts, as well as Robonaut 2, the dexterous humanoid astronaut helper, to the International Space Station. Discovery, which will fly its 39th mission, is scheduled to be retired following STS-133. This will be the 133rd Space Shuttle Program mission and the 35th shuttle voyage to the space station. For more information on the STS-133 mission, visit www.nasa.gov/mission_pages/shuttle/shuttlemissions/sts133/. Photo credit: NASA/Jim Grossmann