To the editors:

One of Cecil Adams’s recent columns dealt with the issue of explosive decompression [March 22]. Although your information was good, you should have mentioned the case history of near rapid decompression which killed three cosmonauts in 1971. Below is an excerpt from my 1990 book, Almanac of Soviet Manned Space Flight.

“At 1:35 A.M., June 30, the crew fired the Soyuz retro rockets to deorbit and twelve minutes later separated from the orbital and service modules. At this time, the orbital module was normally separated by 12 pyrotechnic devices which were supposed to fire sequentially, but they incorrectly fired simultaneously, and this caused a ball joint in the capsule’s pressure equalization valve to unseat allowing air to escape. The valve normally opens at low altitude to equalize cabin air pressure to the outside air pressure. This caused the cabin to lose all its atmosphere in about 30 seconds while still at a height of 168 km. In seconds, Patsayev realized the problem and unstrapped from his seat to try and cover the valve inlet and shut off the valve, but there was little time left. It would take 60 seconds to shut off the valve manually and Patsayev managed to half close it before passing out. Dobrovolsky and Volkov were virtually powerless to help since they were strapped in their seats, with little room to move in the small capsule and no real way to assist Patsayev. The men died shortly after passing out. Fifteen and a half minutes after retrofire, the pressure reached zero in the capsule and remained that for eleven and a half minutes, at which point the cabin started to fill with air from the upper atmosphere. The rest of the descent was normal and the capsule landed at 2:17 A.M. The recovery forces located the capsule and opened the hatch only to find the cosmonauts motionless in their seats. On first glance they appeared to be asleep, but closer examination showed why there was no normal communication from the capsule during the descent.

“The Soviets had to give a detailed report on the accident to NASA, in preparation for the Apollo-Soyuz Test Project, during which they said that the amount of tissue damage to the cosmonauts’ bodies caused by the boiling of their blood during the 11.5 minutes of exposure to vacuum could at first have been misinterpreted as being the result of a catastrophic and instantaneous decompression. The cause of death was pulmonary embolism. Only through analysis of the telemetry records could the failure of the valve be determined. The telemetry showed that the altitude control thrusters had automatically fired to counteract the force of the air escaping from the valve. Examination also found traces of pyrotechnic residue in the valve which also proved that the valve had opened when the pyrotechnics were fired. NASA verified these conclusions after viewing the telemetry data.”

Dennis Newkirk

Fairfax, Virginia