Nando Times

Russian space officials prepare to realign Mir

By VLADIMIR ISACHENKOV, Associated Press

MOSCOW (March 21, 2001 6:45 a.m. EST) - With the Mir space station on the designated low orbit, space officials prepared Wednesday for the delicate job of stabilizing the station. The maneuver is considered essential for the success of its controlled plunge into the South Pacific.

The station lowered to an altitude of 132 miles on Wednesday - the orbit designated as a starting point for the descent process that is to culminate Friday, said Mission Control spokesman Valery Lyndin.

"The next step will be bringing Mir to a stable position on Thursday," he said.

Mir has been in a slow rolling motion since the end of January as space officials tried to save its unstable batteries and precious fuel for the re-entry. Mission Control officials have acknowledged that switching on its computer-controlled orientation system could be tricky.

In December, Mission Control lost contact with the station for more than 20 hours because the batteries suddenly lost power. Space officials have managed to retain contact with Mir during several subsequent power losses, but each of those incidents disabled its central computer for several days.

Fearing that Mir's unstable batteries could cause similar glitches, Mission Control experts have worked out a backup - using the onboard computer and separate radio communications of the Progress cargo ship docked at the station.

If Mir's position isn't stabilized, the re-entry process will become uncontrollable.

Mir's central computer has remained in the so-called "indicator regime," providing data about the station's systems, which are working normally, Lyndin said. Early Thursday, Mission Control will begin sending computer commands to switch on Mir's orientation system and fire thrusters to steady the station, he said.

The key will be to orient the orbiting station with the sun in such a way that the solar panels can soak up the maximum amount of energy possible to charge the batteries.

If the process goes smoothly and Mir remains stable, the Progress will fire its engines twice for about 20 minutes Friday morning, at around 3:30 a.m. Moscow time (7:30 p.m. EST Thursday) and 5 a.m. Moscow time (9 p.m. EST Thursday) during consecutive orbits. That will slow the station and change its orbit from round to elliptical.

Then, at around 8 a.m. Moscow time (midnight Thursday EST), Progress engines will fire one last time for 23 minutes to send the station hurtling into the South Pacific between Australia and Chile. Most of Mir is expected to burn up in the atmosphere during the fiery re-entry, but up to 27.5 tons of debris are expected to reach the Earth surface.

Space officials voiced confidence that they could carry out a safe descent, pointing to their experience in dumping dozens of Progress ships and other spacecraft into the same area of the Pacific the same way.

But the 143-ton station is by far the heaviest spacecraft ever dumped, and its dimensions and shape make it difficult to exactly predict the re-entry.

All engine thrusts would be conducted over Russian territory to allow Mission Control to get maximum information from ground radars. Once the Progress engine fires the last time, Mir will head down over China and Japan - and will be invisible to Mission Control.

Russian space officials said there was no way to track the Mir after it heads down and quickly locate where the debris went.

-- Rachel Gibson (rgibson@hotmail.com), March 21, 2001