. SOYUZ TM25

Flight Crew

TSIBLIYEV, Vasily Vasilyevich, 42, Russian Air Force, commander, 2nd mission

Previous mission: Soyuz TM17 (1993)

LAZUTKIN, Alexandr Ivanovich, 39, civilian, flight engineer EWALD, Reinhold, 40, German cosmonaut researcher

Flight Log

Following the docking of TM25 to Mir on 12 February and the transfer of the cosmonauts to the station, there were six crew members aboard once again. The Mir EO-22 crew of Korzun and Kaleri now included NASA astronaut Linenger, who had arrived the month before. The Mir EO-23 crew of Tsibliyev and Lazutkin would continue their mission with Linenger after Ewald had completed his 18-day research programme and returned to Earth with the EO-22 cosmonauts. The EO-23 crew would also work with Mike Foale, who would replace Linenger in May 1997. Theirs would be an eventful and challenging residency, with the 23 February fire aboard the station and the 25 June collision of Progress M34 to contend with.

Ewald’s research centred on medical experiments to study the effects of micro­gravity on human performance, the function of both hormones and the cardiovascular system, and related psychological effects. In addition, he had a programme of technological and materials processing experiments. Following the fire on board the station, Ewald completed his experiments and prepared for the return to Earth with the EO-22 crew, leaving Mir on 2 March aboard Soyuz TM24.

The EO-23 crew now settled down to their research programme, but the science schedule was frequently interrupted by essential maintenance work on the Mir’s aging systems. One of these repairs was to deal with reported coolant system leaks, which sprayed ethylene glycol into the station’s atmosphere, reaching dangerous levels at

times. Again, delays in supplying a new Soyuz R7 launch vehicle meant that the Russians were told they would have to extend their mission by six weeks. On 29 April, Jerry Linenger became the first American to perform an EVA from a space station (for 4 hours 49 minutes) since the Skylab crews some 23 years previously. Linenger also became the first US astronaut to use a Russian EVA suit. This was a new variant called Orlan-M, which was the latest update to the basic Orlan suit that had been used since 1978. Orlan-M would also be used on early Russian EVA operations at ISS.

During the EVA, the crew installed the Optical Properties Monitor on Kristall and removed some US experiments that would be returned to Earth on STS-84. The EO-23 crew were scheduled to make two further EVAs in June, but other events precluded these from taking place.

Following the next exchange of NASA crew members in May 1997, Mike Foale became the fifth astronaut to work on the Mir station. He had a busy science programme planned that would complement that of the Russian cosmonauts, though most of their time was still being taken up with housekeeping and maintenance. On 25 June, Tsibliyev attempted to re-dock Progress M34. An attempt to use the TORU remote control system had failed during Progress M33 operations in March and in order for the system to be re-qualified for use, Tsibliyev found himself having to try to perform an operation that he had had little training for. When the Progress approached, the cosmonaut realised that it was not responding to commands as it should have been and tried to guide it past the station for another attempt. However, it collided with the Spektr module, puncturing the pressurised compartment and damaging the solar arrays. As alarms sounded, the air inside the station rapidly began leaking into the vacuum of space. Internal power and instrument connections leading from the core module to Spektr were severed and the crew were able to seal the hatch, shutting off the module (and with it, most of Foale’s equipment and personal possessions) and the leak. In the days that followed, Mir suffered other problems, including an inadvertent crew error that caused the station to drift, losing solar lock. It took a Herculean effort that tested all three crew members to finally bring the station back under control and avoid the need for an emergency evacuation. It had been hoped that Tsibliyev and Lazutkin could perform EVAs to effect repairs, but concerns over the health of the commander put these plans on hold until the arrival of the next crew. After much discussion between Russian and American space officials and the astronaut himself, it was decided that Foale would remain on the station with the replacement crew, as planned.

Even the end of the EO-23 mission was not trouble-free. The re-entry burn occurred on time and the parachute deployed, but the soft-landing rockets that should have fired 1.5 metres off the ground failed, resulting in a 7.5 m/sec landing impact. The seat shock absorbers saved the crew from serious injury. Post-flight investigation revealed that the soft-landing rockets had fired, but at 5.8 km altitude. Initially blamed for the collision with Progress, the crew were eventually cleared of all responsibility, although neither ever flew again. It was later determined that the mass of trash inside the Progress had been miscalculated by a ton. This meant that the manoeuvring and braking burns were not as effective as they should have been, thus making Progress arrive quicker and close in more rapidly than estimated.

Milestones

195th manned space flight 84th Russian manned space flight 77th manned Soyuz mission 24th manned Soyuz TM mission 23rd Mir resident crew

30th Russian and 64th flight with EVA operations

1st US EVA in a Russian spacesuit

Tsibliyev celebrates his 43rd birthday in space (20 Feb)