Launch set for 7:59 a.m. MDT. Six hours, 12 minutes after launch, during the fifth orbit, astronauts release a Tracking and Data Relay Satellite from the cargo bay. Activate experiments to process materials and study the effect of weightlessness on red blood cells and organic materials.
Continue previous experiments and start others that examine the influence of weightlessness on crystals and other substances, photograph lightning in the atmosphere and demonstrate the feasibility of using infrared communications links in space.
Continue experiments. Photograph the horizon "twilight glow" before sunrise and after sunset. Practice re-entry procedures, including donning pressure suits and setting up a telescoping pole that the astronauts would slide down if they had to bail out during landing.
Astronauts hold an in-flight news conference. Deactivate experiments, stow equipment and prepare for return to Earth.
Fire deorbit engines and start an hourlong descent, with landing at Edwards Air Force Base, Calif., set for 8:55 a.m. MDT on Monday, after a flight of four days and 55 minutes.