Mir on the last lap

The altitude of the Russian space station Mir fell yesterday to 251km which may be estimated as critical. All space-borne control systems are reportedly in order. When Mir's altitude falls to 250km, the conditions of the station's systems, the atmospheric variables and Mission Control's readiness to handle a 137-ton station must be tested. Mir's altitude falls by 1,800 to 2,000 meters daily. On March 20, it will reach the 220-kilometre mark. At that time, the Russian tracking stations will monitor the switching on and off of the braking engines but not the actual fall and disintegration of the station. This will not, however, affect the safety of the descent, because its path will follow that of Progress cargo vehicles, Soyuz manned spacecraft and earlier generation Salyut space stations.