Soyuz 17

Soyuz 17 (Template:Langx, Union 17) was the first of two long-duration missions to the Soviet Union's Salyut 4 space station in 1975. The flight by cosmonauts Aleksei Gubarev and Georgy Grechko set a Soviet mission-duration record of 29 days, surpassing the 23-day record set by the ill-fated Soyuz 11 crew aboard Salyut 1 in 1971.

Mission parameters

• Mass: Template:Cvt<ref name="Display">Template:Cite web Template:PD-notice</ref>
• Perigee: Template:Cvt<ref name="Trajectory">Template:Cite web Template:PD-notice</ref>
• Apogee: Template:Cvt
• Inclination: 51.6°
• Period: 91.7 minutes

Mission highlights

Salyut 4 was launched 26 December 1974, and Soyuz 17, with cosmonauts Georgy Grechko and Aleksei Gubarev as its first crew, was launched 16 days later on 10 January 1975.<ref name=newkirk>Template:Cite book</ref> Gubarev manually docked Soyuz 17 to the station on 12 January 1975, and upon entering the new station he and Grechko found a note from its builders which said, "Wipe your feet"!<ref name=newkirk/>

Salyut 4 was in an unusually high circular orbit of Template:Cvt when Soyuz 17 docked with the station. Salyut designer Konstantin Feoktistov said this was to ensure propellant consumption would be half of what was needed for lower-altitude Salyuts.<ref name=clark>Template:Cite book</ref>

The crew worked between 15 and 20 hours a day, including their 2Template:Frac hour exercise period.<ref name=newkirk/> One of their activities included testing communication equipment for tracking ships and contacting mission control via a Molniya satellite.<ref name=newkirk/> Astrophysics was a major component of the mission, with the station's solar telescope activated on 16 January 1975.<ref name=clark/> The crew later discovered that the main mirror of the telescope had been ruined by direct exposure to sunlight when the pointing system failed. They resurfaced the mirror on 3 February 1975 and worked out a way of pointing the telescope using a stethoscope, stopwatch, and the noises the moving mirror made in its casing.<ref name=newkirk/>

On 14 January 1975, a ventilation hose was set up from Salyut 4 to keep the Soyuz ventilated while its systems were shut down.<ref name=newkirk/> On 19 January 1975, it was announced that ion sensors were being used to orient the station, a system described as being more efficient.<ref name=clark/> A new teleprinter was used for communications from the ground crew, freeing the Salyut crew from constant interruptions during their work.<ref name=clark/>

The cosmonauts began powering down the station on 7 February 1975 and they returned to Earth in the Soyuz capsule two days later, on 9 February 1975.<ref name=clark/> They safely landed near Tselinograd in a snowstorm with winds of 72 km/h and wore gravity suits to ease the effects of re-adaptation.<ref name=newkirk/>

Soyuz-17 Cliff in Antarctica is named after the mission.