Spaceflight Now: Space Station Mir

Discarded Progress deorbits; Mir enters stabilized mode

Posted: January 29, 2001

A Progress spacecraft. Photo: NASA
The Progress M43 cargo spacecraft, which undocked from Russia's space station Mir on January 25, reentered Earth's atmosphere Monday where it burned up.

The spacecraft fired its braking engine at 0258 GMT (9:58 p.m. EST Sunday) and according to calculations of the mission control in Korolev, the ship's debris, which survived the reentry fell into a designated area of the ocean.

The Progress M43 remained in orbit longer than normal as a back up for the new cargo craft Progress M1-5, which successfully docked to Mir on January 27.

The Progress M1-5 delivered 2,677-kilogram propellant cache critically needed for Mir deorbiting operations currently planned for the beginning or middle of March 2001.

If Progress M1-5 failed to dock with Mir, the mission control in Korolev, could have tried to re-dock Progress M43 to the station. The cargo ship carried food rations and air supplies onboard, which the emergency crew could use, if it had to travel to Mir to facilitate the docking between Progress M1-5 and the station.

In the meantime, soon after docking between Mir and Progress M1-5, ground controllers in Korolev sent Mir into a slow spin. Spin stabilization will preserve the propellant onboard and evenly distribute the exposure of the station's solar panels to the sun.

According to the mission control, the station is fully under control and should be ready for deorbiting on March 6. Depending on the condition of the upper atmosphere, the actual reentry date might be one or two days off the target date.

The regular peak of solar activity, which takes place approximately every 11 years, causes wild fluctuations in the density of the Earth atmosphere. The phenomena makes more diffucult to predict the atmospheric drag, which causes low-orbiting spacecraft, including Mir, gradually spiral down toward denser atmosphere and ultimately reenter.