failure, and to health problems caused by fumes from chemicals used to develop film from the station’s surveillance cameras.
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| Soyuz 23 | October 14-16, 1976 | |
| Vyacheslav Zudov, Valeri Rozhdestvenski Crew code name—Radon Failed to dock with Salyut 5. | ||
| Soyuz 24 | February 8-25, 1977 | |
| Viktor Gorbatko, Yuri Glazkov Crew code name—Terek The cosmonauts entered the station wearing breathing masks, apparently because of the problems encountered on Soyuz 21, but the air proved safe to breathe. The main purpose of their mission seems to have been to tie up loose ends generated by the precipitous departure of the Soyuz 21 crew. They loaded the Salyut 5 Earth-return capsule with samples and film. It detached the day after their departure from the station, on February 26, and was recovered. The Soyuz 24 crew conducted Earth observation and materials sciences experiments. They also conducted an air replacement engineering experiment with implications for future Progress freighter operations. Air was released from the forward end of the station while simultaneously being replaced from storage tanks in the Soyuz 24 orbital module. | ||
2.7 Salyut 6/DOS-5 (September 29, 1977-July 29, 1982)Salyut 6 (figure 2-9) was the first second-generation DOS-type Salyut space station. |
 Figure 2-9. Salyut 6, the third DOS station to be manned. Addition of the aft port (left) forced redesign of the main propulsion system. |
