GRAIL launch Tweetup participants pose for a group photograph Wednesday, September 7, 2011, at the NASA Kennedy Space Center in Cape Canaveral, Fla. Photo Credit: (NASA/Bill Ingalls)
GRAIL launch Tweetup participants pose for a group photograph Wednesday, September 7, 2011, at the NASA Kennedy Space Center in Cape Canaveral, Fla. Photo Credit: (NASA/Bill Ingalls)