TIM FURNISS / LONDON
The European Space Agency has cleared Spanish astronaut Pedro Duque to fly on the Soyuz TMA-3 mission to the International Space Station (ISS) in October. Thedecision follows an investigation into the ballistic re-entry made by the TMA-1 craft returning from the ISS on 4 May.
The probe revealed faults bythe TMA-1 crew, Russia's Nikolai Budarin and NASA's Ken Bowersox and Don Pettit, which could have been the result of a lack of training. Although not publicly disciplined, the crew have been "mildly chastised", it has been reported, and improvements will be made to training for future flights.
Modifications are being made to reduce the chance of incorrect commands by crew members after the TMA-1 crew switched on the Kurs rendezvous-docking system by mistake during re-entry.
This error did not result in the later switch to a ballistic re-entry mode, however. This was caused by a failure in the Busp-M guidance system that controls the traditional re-entry using gyroscopes and accelerometers to send commands to the craft's attitude control system.
The yaw control channel on the Busp unit produced undefined readings indicating a malfunction, causing higher control functions to take the Busp system out of the control loop and convert to a steeper, higher-g ballistic re-entry. The Busp had flown on 49 faultless re-entries since 1979.
As a result of the malfunction, the craft landed 400km (250 miles) short of the intended landing site. The search aircraft heading for the prime landing zone was unaware of the problem even though it was in radio contact with the crew. The crew failed to mention the ballistic re-entry. Mistakes were made in landing procedures with the result that onboard antennas were not deployed and the radio was not switched to an external transmitter once the crew had erected an antenna outside.
Communications with the recovery teams could have been improved considerably had the crew had a mobile satellite telephone aboard the spacecraft, the investigation concluded. This will become standard equipment on future flights.
A mobile unit will be delivered to the ISS to be used by the crew returning in the TMA-2, now docked to the station.
Source: Flight International
