Space shuttle Endeavour’s astronauts performed a checkout of the orbiter’s flight control surfaces. This standard day-before-entry test provides assurance to the crew and Mission Control that Endeavour’s elevons and speed brake will provide control once the shuttle enters the atmosphere for Wednesday’s 2:35 a.m. EDT landing.
The crew will “hotfire” Endeavour’s Reaction Control System thruster jets to verify their ability to steer the shuttle through its entry profile before it encounters the atmosphere.