The Endeavour crew prepares to depart the International Space Station tonight. They are scheduled to land back home on Wednesday evening. Their relaxation time is now over and they are preparing to close down the hatches prior to the undocking procedure, which will precede their stressful descent to Earth.

This is a somewhat abrupt change from yesterday's leisurely time, when they were awakened at 12:28 p.m. by a recording of "I am Free" beamed up from Mission Control, a song recorded by members of astronaut Mike Foreman's church near the Johnson Space Center. Yesterday, only minor tasks were scheduled, such as transfer of items and samples which need to get back on Earth to the shuttle. The light schedule allowed for more rest time which is needed to prepare for the return trip.

"The final thing that's kind of on the open to-do list is the very important crew photo. That's where both the station and shuttle crew will get together and take sort of a goodbye photo, a team photo, of everyone together," said yesterday space station Flight Director Bob Dempsey to CBS News.

Shuttle commander Dominic Gorie and his crew will undock from the station at 7:56 p.m. EDT, about a couple of hours after closing down the hatches. "We've seen some incredible changes on the station and it's been a real privilege to be here and see all that," said the station's Expedition 16 commander Peggy Whitson to Space.com

Their sixteen day mission was not only mentally stressful, but also involved many old-fashioned physical tasks with low-tech tools such as hammers and pry bars. However, the highly trained crew overcame unexpected troubles and managed to successfully install the first part of the Japanese space agency's new laboratory module, Kibo, and Canada's new robotics system -- the Special Purpose Dexterous Manipulator, or Dextre.

Landing is set for Wednesday evening at 7:04 p.m. EDT (2304 GMT) at NASA's Kennedy Space Center in Cape Canaveral, Fla.