NASA Tweetup participants stand at the launch clock, Thursday, Feb. 24, 2011, prior to the launch of the space shuttle Discovery (STS-133) at Kennedy Space Center in Cape Canaveral, Fla. During the 11-day mission, Discovery will deliver the Italian-built Permanent Multipurpose Module (PMM) and Express Logistics Carrier 4 (ELC4) along with another Robonaut 2, which will become the first humanoid robot in space. Discovery, on its 39th and final flight, is NASA's most flown shuttle. Photo Credit: (NASA/Paul E. Alers)
