Launch from the Baikonur Cosmodrome; landing
202 km east of Dzhezkazgan.
Following a one day solo flight Soyuz 11
docked with the space station
June 07, 1971. The crew transferred into the station. It was the first space
station flight in space history.
The crew performed different
scientific work in the areas of biology, astronomy and Earth observation were
part of the scientific work. The main instrument, a large solar telescope, was
inoperative because its cover failed to jettison. The mission was cut short due
of problems aboard the station including an electrical fire. The planned
highlight of the mission was to have been the observation of an N-1 booster
launch, but the launch was postponed. The crew also found that using the
exercise treadmill as they were required to do twice a day caused the whole
station to vibrate.
During the landing operations a pressure
equalization valve was opened prematurly and the cosmonauts perished due to a
loss of cabin atmosphere and of non-wearing of pressure suits. As a result of
this disaster pressure suits were worn during launch, docking maneuvers and
reentry in the following missions.
It quickly became apparent that they
had asphyxiated. The fault was traced to a breathing ventilation valve, located
between the orbital module and the descent module, that had been jolted open as
the descent module separated from the service module, 723 seconds after
retrofire. The two were held together by explosive bolts designed to fire
sequentially; in fact, they fired simultaneously. The force of this caused the
internal mechanism of the pressure equalization valve to loosen a seal that was
usually discarded later and normally allowed automatic adjustment of the cabin
pressure. The valve opened at an altitude of 168 kilometers (104 mi), and the
gradual loss of pressure was fatal within seconds. The valve was located
beneath the seats and was impossible to find and block before the air was lost.
Flight recorder data from the single cosmonaut outfitted with biomedical
sensors showed cardiac arrest occurred within 40 seconds of pressure loss. By
935 seconds after the retrofire, the cabin pressure was zero, and remained
there until the capsule entered the Earth's atmosphere.