Soyuz 17

Mission type	Docking with Salyut 4
Operator	Soviet space program
COSPAR ID	1975-001A
SATCAT no.	07604
Mission duration	29 days 13 hours 19 minutes 45 seconds
Orbits completed	479
Spacecraft properties
Spacecraft	Soyuz 7K-T No.5
Spacecraft type	Soyuz 7K-T
Manufacturer	NPO Energia
Launch mass	6570 kg[1]
Landing mass	1200 kg
Crew
Crew size	2
Members	Aleksei Gubarev Georgy Grechko
Callsign	Зенит (Zenit - "Zenith")
Start of mission
Launch date	10 January 1975, 21:43:37 UTC
Rocket	Soyuz
Launch site	Baikonur, Site 1/5[2]
End of mission
Landing date	9 February 1975, 11:03:22 UTC
Landing site	110 km at the northeast of Tselinograd, Kazakhstan
Orbital parameters
Reference system	Geocentric orbit[3]
Regime	Low Earth orbit
Perigee altitude	293.0 km
Apogee altitude	354.0 km
Inclination	51.6°
Period	91.7 minutes
Docking with Salyut 4
Docking date	12 January 1975
Undocking date	9 February 1975
Time docked	28 days
Vimpel Diamond patch Soyuz programme ← Soyuz 16 Soyuz 7K-T No.39 →

Soyuz 17 (Russian: Союз 17, 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.

Position	Cosmonaut
Commander	Aleksei Gubarev First spaceflight
Flight Engineer	Georgy Grechko First spaceflight

Position	Cosmonaut
Commander	Vasily Lazarev
Flight Engineer	Oleg Makarov

Position	Cosmonaut
Commander	Pyotr Klimuk
Flight Engineer	Vitaly Sevastyanov

• Mass: 6,570 kg (14,480 lb)^[1]
• Perigee: 293.0 km (182.1 mi)^[3]
• Apogee: 354.0 km (220.0 mi)
• Inclination: 51.6°
• Period: 91.7 minutes

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.^[4] 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"!^[4]

Salyut 4 was in an unusually high circular orbit of 350 km (220 mi) 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.^[5]

The crew worked between 15 and 20 hours a day, including their 21⁄2 hour exercise period.^[4] One of their activities included testing communication equipment for tracking ships and contacting mission control via a Molniya satellite.^[4] Astrophysics was a major component of the mission, with the station's solar telescope activated on 16 January 1975.^[5] 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.^[4]

On 14 January 1975, a ventilation hose was set up from Salyut 4 to keep the Soyuz ventilated while its systems were shut down.^[4] On 19 January 1975, it was announced that ion sensors were being used to orient the station, a system described as being more efficient.^[5] A new teleprinter was used for communications from the ground crew, freeing the Salyut crew from constant interruptions during their work.^[5]

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.^[5] 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.^[4]

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