Tim Furniss/KENNEDY SPACE CENTER
By 7 August, Russia's Soyuz TM26 should have arrived at the troubled Mir space station. It will be a member of the next mission to the Mir who will be most worried about the success of the TM26, however. US astronaut Navy Cdr Wendy Lawrence is part of the Space Shuttle STS86/Atlantis team - the seventh Shuttle Mir Mission (SMM) - due to be launched on 18 September. It is her job to replace colleague Michael Foale for a working shift aboard the Russian space station, but, if 20% of the electrical power to the Mir cannot be restored by TM26 cosmonauts Anatoli Solovyov and Pavel Vinogradev, there will be calls for the cancellation of Lawrence's mission.
Such a move could spell the end of the SMM programme, although NASA and the Russian Space Agency will fight such a move vigorously, for many reasons.
The SMMs provide valuable assistance to the Mir and essential logistic support. "It would be a problem for the Mir without the Shuttle coming and going," says SMM director Frank Culbertson. NASA also wants more astronaut experience in long-term spaceflight and working with Russian colleagues in space and on the ground, in preparation for operations aboard the International Space Station (ISS).
Russia can earn valuable fees from customer flights to the Mir. A French astronaut's trip, scheduled for January 1998, is worth $20 million to Russia. Finally, abandoning the SMM programme or the Mir itself will provide ammunition for ISS critics in the US Congress.
RUNNING REPAIRS
Solovyov and Vinogradev are due to arrive at the Mir on 7 August. By 20 August, they will be into their first repair mission - an internal spacewalk in the node/connector airlock of the station to reconnect the electrical cables from the three remaining solar panels on the Spektr module to the Mir's main electrical supply.
One of the Spektr's arrays was damaged by the collision of the Progress M35 on 25 June, which also caused a slow depressurisation of the Spektr. To seal off its hatch from the rest of the station after the incident, the electrical cables between it and the rest of the Mir had to be pulled out by the resident crew.
Solovyov and Vonogradev will attempt to reconnect them by fitting a customised unit over the existing Spektr hatch, to enable the cables to run into the Mir while allowing the hatch to remain closed. The cables from the Spektr will be plugged into one side of the new cover and the cables from the rest of Mir to the outer part, with the mating resulting, it is hoped, in restoration of power.
If this is successful, the electrical power on the Mir will be increased to 70%, enough to assist the working of its attitude-control systems and to bring the two science modules, the Priroda and Kristall, to full working order. About 60% of the US experiments are in the Priroda and 40% were lost when the Spektr depressurised.
The reason a full 100% power capability cannot be regained is partly because of the loss of the fourth Spektr solar panel and because of the need to align the remaining panels to the Sun so that a proper thermal balance can be maintained.
The second of maybe six spacewalks by the TM26 duo will be to inspect the exterior of the Spektr module to see whether it can be repaired. They may also try to enter the Spektr to assess damage caused by the vacuum and low temperatures. This may be attempted during the end of the first internal spacewalk if time allows.
Later spacewalks may try to repair or replace the fourth solar panel on the Spektr. Russian officials are working on a new adhesive which may be able to breach the small hole in the hull, says Yuri Baturin, secretary of the Kremlin Defence Council. "Rumours of the death of the Russian space programme are not only exaggerated, but are wrong," he says.
The NASA SMM 7 mission may also be able to bring new equipment to the station. The cargo may include a cutting tool to enable the TM26 duo to remove Spektr's damaged panel and eventually replace it. As 40% of the US science experiments - as well as much of Foale's personal items - were inside the Spektr, NASA will be keen to replace or retrieve them. The STS86 crew includes Vladimir Titov, who spent a year on the Mir in 1987-8, and his experience may prove invaluable.
It is expected that the flight plan for the SMM 7 will be amended right up to launch, and even during the mission. A decision on whether Lawrence stays or comes back on the Atlantis in September may not even be made until it is time for the Shuttle to undock. Foale will return as planned on the Atlantis while his crewmates, Vasily Tsiblyev and Alexander Lazutkin, are due to land in their Soyuz TM25 on 14 August.
Source: Flight International
