If weather and spacecraft systems cooperate, Discovery will touch down at Kennedy Space Center at 11:04 a.m. Central time after completing 134 orbits of the Earth. Deorbit ignition of the orbiter's maneuvering engines will occur at 9:53 a.m. CST to slow the spacecraft's forward velocity, allowing it to drop back into the Earth's atmosphere. Returning as an unpowered hypersonic glider, Discovery will follow a ground track taking it across Texas and Louisiana before it sweeps out over the Gulf of Mexico and into Florida.
Weather in Florida is predicted to be near but within acceptable margins for crosswinds and clouds.
Today there are two landing opportunities at KSC and two to Edwards Air Force Base, California. Discovery has a second chance to land at KSC at 12:45 p.m. CST or could land at Edwards at either 12:35 p.m. or 2:17 p.m. Weather at Edwards is predicted to be good on Saturday but unacceptable on Sunday. KSC weather will be near margins both days. Flight controllers will try both opportunities into KSC before considering the Edwards landing.
Although a normal entry, approach, and landing are expected, precautionary plans are in place to accommodate a deployment of Discovery's drag chute during reentry. The Shuttle Training Aircraft that performs routine weather observations prior to landing and during final approach will also visually monitor Discovery's drag chute compartment.
If Discovery lands today, the astronauts will spend the night at KSC before returning to Houston mid-day on Sunday to a welcome at Ellington Field.