The astronauts aboard the shuttle-station complex will celebrate the 40th anniversary of man's first moon landing with their own spacewalk.
Late Monday morning, David Wolf and Thomas Marshburn will venture out to hook spare parts to the international space station. It will be the second spacewalk in three days, and take place 40 years to the day that Neil Armstrong and Buzz Aldrin walked on the moon.
The space station crew, meanwhile, will spend Monday working on a broken toilet. One of the station's two commodes malfunctioned Sunday
For the time being, the 13 astronauts are lining up at the two good toilets, one on the station and one on Endeavour. NASA says it hasn't yet become a serious problem.