Three space station crew members headed home

Half the International Space Station's six-person crew has begun a roughly three-hour journey home to Earth.

At 8:23 p.m. EST, hooks and latches on the Rassvet module released the Soyuz TMA-19 spacecraft carrying American astronauts Doug Wheelock and Shannon Walker and Russian cosmonaut Fyodor Yurchikhin.

"We have separation," Yurchikhin, commander of the Soyuz known as "Olympus," radioed to mission controllers in Moscow.

The undocking officially ended the station's 25th expedition and a more than five month residence for the three departing crew members.

Their destination: north-central Kazakhstan, where snow and freezing rain are falling and temperatures are in the teens.

An engine burn planned at 10:55 p.m. EST and lasting about four minutes will drop the Soyuz from orbit.

Twenty-five minutes later, the spacecraft's upper and lower modules will split away, leaving only the descent module holding the crew as it plunges toward the atmosphere.

Atmospheric re-entry is expected to begin at 11:23 a.m. The spacecraft will deploy parachutes about nine minutes later and touch down at 11:46 p.m. EST.

You can watch the Thanksgiving Day landing (Eastern time) live here -- click on the NASA TV box at right to launch a viewer.