ISS crew repairs three of the four faulty gyroscopes

The crew of the International Space Station (ISS) has repaired three of the four gyroscopes that are responsible for the ISS orientation, Vladimir Solovyov, flight controller of the Russian segment, told journalists immediately after the ISS crew, which had worked in open space for six hours, returned to the station.

"The crew soon saw that they can do it and by the middle of the job Padalka and Fink became over-energetic," said Solovyov. Flight engineer Michael Fink worked in the same spacesuit he wore during the previous failed mission in open space in the night of June 24/25.

"Don't trouble trouble, they say, and though I assured you that spacesuit would not be used again, Michael wore it this time," said the Russian official. In his words, the two-man crew of commander Gennady Padalka and flight engineer Michael Fink "worked very well; we could see on the monitors that they wanted to finish the job maximally quickly." They completed the drawn-out repairs of the faulty US gyroscope on July 1.

Since they worked 40 minutes ahead of schedule, the crew also did several additional jobs; in particular, they mounted engineering equipment on the outer surface of the Russian docking module Pirs.

The first emergency job in outer space in the night of June 24/25 lasted only 10 minutes and was cut short because of a sharp fall of oxygen pressure in Fink's spacesuit. It turned out later that he had not turned fully on the injector lever that injects oxygen into the spacesuit. This is why pressure plummeted and the crew had to rush back to the station.

Padalka and Fink replaced the electricity supply remote control block of the US-made gyroscope, which called for turning electricity off in the US module for a short time. According to the Russian Flight Control Centre, the initial programme of the 9th mission (Padalka and Fink) provided for two routine space walks: in late July and in late August. But life changed these plans.

As of now, the ISS orientation is ensured by the three working gyroscopes of the station's four and by Russian jet micro-engines. At first, the crew planned to use the US EMU spacesuits for repairing the second gyroscope on June 10. All preparatory measures for the crew and for surface services were planned for this day. But it turned out that the cooling system of one of the suits was not working. By the suggestion of the US side, the crew worked in the Russian Orlan M spacesuits, which called for changing the schedule of preparations for and the cycles of work in outer space, because the crew moved to the gyroscopes not from the American but from the Russian module. Consequently, the date was set for June 16.

American medics thought the optimal date would be June 28, as the change in the work and sleep routine of the crew would be balanced with the astronauts' biological rhythms. The medics said a disruption of the rhythm would reduce the effectiveness of work.

But the Russian doctors do not care so much for biological factors. For Russian specialists, the key factor for choosing the date and time of working in outer space is the availability of maximum radio communication zones through Russian ground-based stations, which ensures full-scale control of the astronauts' work and health. That condition could not be fulfilled on June 28. At the American request, the joint groups of Russian and American specialists made an additional analysis of the situation to choose the new date for the mission and reached a compromise decision, setting it for the night of June 24/25 Moscow time. But it was aborted because of Fink.

Consequently, the second simultaneous mission in outer space in the history of the ISS was completed on the second try.