Mir crew to venture outside After all but winning the battle with an on-board air leak, Mir cosmonauts Sergei Zaletin and Alexander Kalery are now free to prepare for another important task: a spacewalk.
Once outside the station, the cosmonauts hope to test an innovative technique for sealing air leaks in orbital modules. Russian space officials believe the work will have long-term implications for the future of space exploration.
A 1997 orbital collision between the
Progress cargo ship and Mir space station, which almost took the lives of two Russians and one U.S. astronaut, spurred extensive research in Russia on different methods of searching and fixing air leaks on board piloted spacecraft. Other tasks for the Friday spacewalk will include the examination of Mir's surface and solar panels, and deployment of an experimental thin-film solar panel.
In the meantime, the ground controllers are carefully monitoring the pressure inside Mir. Although the atmosphere appears stable, Russian space officials are not in a hurry to declare a victory over the air leak, which has plagued the station since last summer.
Since a special air-generating electrolysis unit in the station now replenishes Mir's atmosphere, it is harder to monitor possible pressure loss inside the station, said Yuri Grigoriev, deputy designer general to RKK Energia, the Russian company operating Mir. The crew reactivated the electrolysis unit soon after its arrival on the station April 6.
The cosmonauts found and plugged a single air leak on Mir last month and mission managers hoped it would end their worries.
If the pressure had continued to fall, the crew would have had to go through a laborious task of removing numerous cables running through the hatches between the Mir's
core module and the adjoining Kvant 1 module. The procedure would allow them to isolate the two oldest components of Mir and check them for leaks individually.Last Friday, the crew finished a two-day test of the
Kvant 2 module for leaks, but it appeared to be airtight.On a higher orbit
Last week, ground controllers and the crew also tackled another problem affecting the station. A newly arrived Progress cargo ship's engines were used to raise the orbit of the outpost. The maneuver was necessary because this year's higher than average solar activity is causing Earth's atmosphere to "bulge." The resulting increase in atmospheric drag could eventually slow the low-orbit station enough to send it on a fiery plummet back to Earth.
After three orbital maneuvers with Progress' engines, Mir climbed to a 240-mile (390-kilometer) high orbit, where the station can safely circle the Earth until the end of the year.
Taking care of science
With most of the housekeeping chores completed, the crew can concentrate on the scientific duties of the mission. One major experiment called Pelena arrived at the station with the latest Progress ship. The experiment will test a 330-pound (150-kilogram) radiator, which uses oil vapor to cool space-based hardware.
The crew plans to deploy the experiment at the end of May or beginning of June.
When to go home?
While RKK Energia still ponders the future of Mir, Zaletin and Kalery will likely have to wrap up their mission and return home rather than wait for a replacement crew to arrive.
This 28th long-duration mission to Mir became possible thanks to private funds raised by MirCorp, which is based in the Netherlands. The company rented the resources of the station from RKK Energia and intends to turn the outpost into a for-profit facility.
The latest plans call for the crew to return home on June 12. The mission could be extended by five or six days, however, since it is ultimately limited by the amount of water and food delivered by the latest Progress. MirCorp has yet to finance another cargo ship launch to Mir and according to Russian space officials, additional money is not expected before June.
Even if RKK Energia decides to deorbit the station at the end of the year, at least one more Progress mission to Mir will be needed.
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