This mission was intended to visit the Salyut
7 space station, which was occupied by the
The crew were sitting on the pad awaiting fueling of the Soyuz-U
booster to complete prior to liftoff. At T-90 seconds, a valve failed to close,
causing liquid kerosene propellant to spill onto the pad and ignite. The launch
control team activated the escape system but the control cables had already
burned, and the Soyuz crew could not activate or control the escape system
themselves. 20 seconds later, launch control was finally able to activate the
escape system by radio command, by which time the booster was engulfed in
flames. Explosive bolts fired to separate the descent module from the service
module and the upper launch shroud from the lower. Then the escape system motor
fired, dragging the orbital module and descent module, encased within the upper
shroud, free of the booster with an acceleration of 14 to 17g (137 to 167
m/s²) for five seconds. Although Titov and Strekalov had no way of seeing
what was going on outside, the former recalled feeling "unusual vibrations".
Just after the escape tower pulled the descent module away, the booster
exploded with its remains burning on the pad for nearly 20 hours. Four
paddle-shaped stabilizers on the outside of the shroud opened and the descent
module separated from the orbital module at an altitude of 650 m, dropping free
of the shroud. The descent module discarded its heat shield, exposing the
solid-fuel landing rockets, and deployed a fast-opening emergency parachute.
Landing occurred about four kilometers from the launch pad. The two crew
members were badly bruised after the high acceleration, but were otherwise okay
and did not require any medical attention.
The explosion and fires
severely damaged LC-1 (the same pad used by Sputnik 1 and
cost an estimated 300 million USD to repair.
Soyuz T-10's descent module
was refurbished and later used on