MOSCOW -- After weeks of uncertainty, Russian space officials have set the early hours of March 22 as the definitive target for the Mir's fiery reentry into Earth's atmosphere.

Mir. Photo: NASA

If everything goes as scheduled, the entire process of deorbiting will take only six hours, during which Mir will make four final orbits around the planet. In case of emergency, the ground controllers have 24 hours to solve problems and complete the operation.

According to Nikolai Anfimov, the chief of TsNIIMash, the main research institution of the Russian space industry, the Progress cargo ship docked to the station will fire its maneuvering trusters for the first time around 0100 GMT on March 22 (8 p.m. EST on 21st). This and the second firing of the Progress engines one orbit later, will leave the Mir on a 220-165-kilometer elliptical orbit.

Mir will then circle the Earth passively one more time, before entering its final orbit. The station's third and last maneuver will start around 0700 GMT (2 a.m. EST) with the firing of the Progress trusters and its main engine joining in later in the burn. The reentry and disintegration of the station will take place in the next thirty minutes.

Although the commands to fire the engines onboard Mir will be transmitted during the station's pass within the range of Russian ground control station, the outpost will leave the communication range at the time of the engine shut down in the final maneuver.

The ground control stations in Ulan-Ude and Petrapavlovsk-Komchatskiy in the Russian Far East will be the last to receive the telemetry from the doomed spacecraft.