Crew of three drop toward icy Asian landing

A Russian Soyuz spacecraft has completed an engine burn to start a plunge from orbit expected to drop it and a crew of three onto the icy, snow-covered plains of Kazakhstan at 2:15 a.m.

Click here to open a NASA TV video player and watch the landing live.

Conditions at the targeted landing site northeast of the remote town of Arkalyk are poor enough that a convoy off all-terrain vehicles may replace the fleet of Mi-8 helicopters typically deployed for crew search and rescue operations.

Two helicopters that lifted off from the northern town of Kustanai were forced to turn back. The ATVs driving roughly 50 miles from Arkalyk in sub-freezing temperatures may not reach the landing site ahead of the spacecraft.

Seated in the Soyuz TMA-15 descent module -- the middle of three -- are its commander, cosmonaut Roman Romanenko, who is flanked by European Space Agency astronaut Frank De Winne to his left and Canadian Space Agency astronaut Bob Thirsk to his right.

The crew closed the hatches to the International Space Station's Zarya module at 7:43 p.m. EST and undocked at 10:56 p.m.

The departure left only American astronaut Jeff Williams and Russian Max Suraev manning the station.

A first, short engine firing separated the spacecraft from the station, followed by the four-minute, 19-second deorbit burn at 1:26 a.m. as the spacecraft flew over the south Atlantic Ocean.

Within 20 minutes, pyrotechnic devices will break apart the three Soyuz modules before it re-enters Earth's atmosphere.

Only the descent module will return to the chilly ground, its plunge slowed by two parachutes around 2 a.m. and thrusters firing just before touchdown.

The return would end a 188-stay in space for the trio that served on the station's Expedition 21.