Tim Furniss/LONDON
RUSSIAN SPACE officials have confirmed that the losses of two Soyuz U boosters on launches from Baikonur and Plesetsk on 14 May and 20 June were caused by defective payload shrouds. Each shroud disintegrated at T+49s (Flight International, 3-9 July).
The Plastik company of Syzran, Russia, which makes the shrouds, says that glue between layers of the glass-reinforced-plastic payload fairing had been incorrectly applied after a change in manufacturing procedures in 1995. As a result, the shroud was weakened and unable to tolerate the aerodynamic pressure. The TsSKB Progress company, of Samara, also admits that payload-shroud latches which it manufactured were defective. The failures and cash shortages had been responsible for the delay to the next planned Soyuz U launch of a Progress M32 unmanned tanker and manned Soyuz TM24 craft to the Mir 1 space station (Flight International, 24-30 July).
The launches were delayed further when the Progress M23 flight from Baikonur - with a new, all-metal payload shroud - was first called off on 22 July, to enable the integrity of the original Samara latches to be double-checked.
The launch was then aborted at T-10s, after a fuel-valve malfunction, on 25 July and cancelled on 27 July. Officials chose to use a new booster, and the Military Space Forces suggested sabotage as the cause of the technical problems.
The Progress M32 was to have delivered 2.4t of fuel, food, and experiments to the Mir. The TM24 launch will not now take place earlier than 19 August.
The Mir is crewed by two Russian cosmonauts and NASA astronaut Shannon Lucid, whose return aboard the Space Shuttle Atlantis/ STS79 has been delayed until mid-September because of the need to replace the solid-rocket boosters for this mission.
Source: Flight International