STS-127 shuttle mission crew members from left, Commander Mark Polansky, Pilot Doug Hurley, Mission Specialists Christopher Cassidy, Tom Marshburn, Dave Wolf and Julie Payette of the Canadian Space Agency, give a presentation at the NASA Tweetup event held at NASA Headquarters, September 24, 2009 in Washington. The NASA Tweetup featured a presentation and a question and answer session with the crew of the STS-127 shuttle mission to install new hardware and expand the Japanese Kibo laboratory on the International Space Station. Photo Credit: (NASA/Carla Cioffi)