Soyuz 25 (Russian: Союз 25, Union 25) was an October, 1977, Soviet crewed space flight, the first to the new Salyut 6 space station, which had been launched 10 days earlier. However, the mission was aborted when cosmonauts Vladimir Kovalyonok and Valery Ryumin failed to engage the docking latches of the station despite five attempts. Lacking sufficient fuel to attempt a dock at the other end of the station and with battery power for only two days, they returned to Earth.[2]
COSPAR ID | 1977-099A ![]() |
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SATCAT no. | 10401 |
Mission duration | 2 days, 44 minutes, 45 seconds |
Orbits completed | 32 |
Spacecraft properties | |
Spacecraft type | Soyuz 7K-T |
Manufacturer | NPO Energia |
Launch mass | 6,860 kilograms (15,120 lb) |
Crew | |
Crew size | 2 |
Members | Vladimir Kovalyonok Valery Ryumin |
Callsign | Фотон (Foton - "Photon" |
Start of mission | |
Launch date | October 9, 1977, 02:40:35 (1977-10-09UTC02:40:35Z) UTC |
Rocket | Soyuz-U |
Launch site | Baikonur 1/5[1] |
End of mission | |
Landing date | October 11, 1977, 03:25:20 (1977-10-11UTC03:25:21Z) UTC |
Landing site | 185 kilometres (115 mi) NW of Tselinograd |
Orbital parameters | |
Reference system | Geocentric |
Regime | Low Earth |
Perigee altitude | 198.5 kilometres (123.3 mi) |
Apogee altitude | 258.1 kilometres (160.4 mi) |
Inclination | 51.66 degrees |
Period | 88.66 minutes |
Soyuz programme (Crewed missions) |
The failure led to a new rule whereby every crew had to have at least one person aboard who had previously flown in space.[3]
Position | Cosmonaut | |
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Commander | Vladimir Kovalyonok First spaceflight | |
Flight Engineer | Valery Ryumin First spaceflight |
Position | Cosmonaut | |
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Commander | Yuri Romanenko | |
Flight Engineer | Aleksandr Ivanchenkov |
Soyuz 25 was launched on 9 October 1977 with a crew of two cosmonauts to dock with the orbiting Salyut 6 space station, which had been launched 10 days earlier, on 29 September.[4] The crew were to stay on board for about 90 days, which would break the Soviet space endurance record, and possibly the all-time record of 84 days held by the crew of Skylab 4.[3] The station was a new version of a Salyut with modifications including a second docking port which allowed supply ships and other crews to visit during the duration of a mission.[4]
The vehicle approached the station the next day, and it contacted the forward port, but the Soyuz craft failed to make a hard dock with the station. The cosmonauts told the ground crew that they had attempted to dock four times, but that the contact light failed to come on. While the crew waited in soft dock - the docking system probe was latched onto the Salyut docking drogue, but the probe had failed to retract and bring the craft together - the ground crew studied the problem.[4]
On the 20th orbit, Kovalenko undocked the Soyuz, and attempted to dock for the fifth time during the 23rd orbit, but failed again. The decision was made to return to earth, as the Soyuz was equipped with batteries designed to last about two days, and the craft lacked fuel to attempt to dock with the port on the opposite side of the station.[4]
A news release was issued: "At 07.09 Moscow time today (10 October) the automatic rendezvous of the Soyuz 25 ship and the Salyut 6 station was begun. From a distance of 120 metres, the vehicles performed a docking manoeuvre. Due to deviations from the planned procedure for docking, the link-up was called off. The crew has begun making preparations for a return to Earth."[3]
The crew thus had to make an early reentry and landed 185 km (115 mi) northwest of Tselinograd, Kazakhstan on 11 October.
The failure was a serious blow to the Soviets, as their media had given the flight a high profile, noting that the flight had come from the same launchpad as Sputnik 1 and Vostok 1,[3] and coincided with the 60th anniversary of the October Revolution.
The problem was traced later to a faulty mechanism on the Soyuz; this was not discovered until after the Soyuz 26 flight performed an EVA to inspect the second docking port on Salyut 6.
The mission failure resulted in a rule stating that future crews would include at least one cosmonaut who had already flown a space mission.[3] This resulted in the all-rookie backup crew of Aleksandr Ivanchenkov and Yuri Romanenko being paired with veteran cosmonauts for future missions. The rule was not relaxed until 1994 and Soyuz TM-19.
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Main topics |
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Past missions (by spacecraft type) |
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Future missions |
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Uncrewed missions are designated as Kosmos instead of Soyuz; exceptions are noted "(uncrewed)". The † sign designates failed missions. Italics designates cancelled missions. |
← 1976 · Orbital launches in 1977 · 1978 → | |
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Kosmos 888 | Meteor-2 No.2 | Kosmos 889 | Kosmos 890 | NATO 3B | Kosmos 891 | OPS 3151 | Soyuz 24 | Kosmos 892 | Molniya-2-17 | Kosmos 893 | Tansei 3 | Kosmos 894 | Unnamed | Kiku 2 | Kosmos 895 | Kosmos 896 | Kosmos 897 | Palapa A2 | OPS 4915 | Kosmos 898 | Molniya-1-36 | Kosmos 899 | Kosmos 900 | Meteor-M No.39 | Kosmos 901 | Kosmos 902 | Kosmos 903 | Kosmos 904 | GEOS-1 | Kosmos 905 | Kosmos 906 | Molniya-3 No.19 | Kosmos 907 | OPS 9437 · OPS 9438 | Kosmos 908 | Kosmos 909 | Kosmos 910 | OPS 9751 | Kosmos 911 | Kosmos 912 | Intelsat IVA F-4 | Kosmos 913 | Kosmos 914 | OPS 5644 | Kosmos 915 | Kosmos 916 | Kosmos 917 | GOES 2 | Signe 3 | Kosmos 918 | Kosmos 919 | Kosmos 920 | NTS-2 | Molniya-1 No.45 | Kosmos 921 | OPS 4800 | Meteor-Priroda No.2-2 | Kosmos 922 | Kosmos 923 | Kosmos 924 | Kosmos 925 | Kosmos 926 | Kosmos 927 | Kosmos 928 | Himawari 1 | Kosmos 929 | Kosmos 930 | Kosmos 931 | Kosmos 932 | Kosmos 933 | Gran' No.13L | Kosmos 934 | Kosmos 935 | Kosmos 936 | TKS-VA No.009P · TKS-VA No.009A | Unnamed | HEAO-1 | Voyager 2 | Kosmos 937 | Kosmos 938 | Kosmos 939 · Kosmos 940 · Kosmos 941 · Kosmos 942 · Kosmos 943 · Kosmos 944 · Kosmos 945 · Kosmos 946 | Sirio 1 | Kosmos 947 | Molniya-1-38 | Kosmos 948 | Voyager 1 | Kosmos 949 | Kosmos 950 | Kosmos 951 | OTS-1 | Kosmos 952 | Kosmos 953 | Kosmos 954 | Kosmos 955 | Ekran No.12L | Prognoz 6 | OPS 7471 | Kosmos 956 | Interkosmos 17 | Salyut 6 | Intelsat IVA F-5 | Kosmos 957 | Soyuz 25 | Kosmos 958 | Kosmos 959 | ISEE-1 · ISEE-2 | Kosmos 960 | Kosmos 961 | Molniya-3 No.18 | Transat | Kosmos 962 | Meteosat 1 | Kosmos 963 | Unnamed | Kosmos 964 | Kosmos 965 | OPS 8781 · OPS 8781 SSU-1 · OPS 8781 SSU-2 · OPS 8781 SSU-3 | Soyuz 26 | OPS 4258 | Kosmos 966 | Kosmos 967 | Meteor-2 No.3 | Sakura 1 | Kosmos 968 | Kosmos 969 | Kosmos 970 | Kosmos 971 | Kosmos 972 | Kosmos 973 | |
Payloads are separated by bullets ( · ), launches by pipes ( | ). Crewed flights are indicated in underline. Uncatalogued launch failures are listed in italics. Payloads deployed from other spacecraft are denoted in (brackets). |