Google translations: From roscosmos.ru Flight from station to station (Перелет со станции на станцию)

35 years ago, on February 20, 1986, the first module of the Mir orbital complex was launched into near-earth orbit. The first expedition arrived at the station on the Soyuz T-15 manned spacecraft (cosmonauts Leonid Kizim and Vladimir Soloviev) and worked in space from March 13 to July 16, 1986. This was the first long-term expedition to the Mir space station and at the same time the last flight to the seventh Salyut.

35 лет назад, 20 февраля 1986 года, на околоземную орбиту был выведен первый модуль орбитального комплекса «Мир». Первая экспедиция прибыла на станцию на пилотируемом корабле «Союз Т-15» (космонавты Леонид Кизим и Владимир Соловьев) и работала в космосе с 13 марта по 16 июля 1986 года. Это была первая долговременная экспедиция на космическую станцию «Мир» и одновременно с этим последний полет к седьмому «Салюту».

There is a slide show with 11 photos and the one below is the 6th. It appears to show a long reinforced truss with a square cross-section and perhaps up to 20 roughly cubic segments. There is what looks like the circular limb of the Earth in the background.

Question: What is this long truss (that I believe is) associated with Mir? What are it's dimensions and what's its purpose?

Mir? from https://www.roscosmos.ru/media/gallery/big/30963/4460290935.jpg from https://www.roscosmos.ru/30963/

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    $\begingroup$ Sorry, I really had to backpedal this time. I re-read the linked article and I updated my answer. It is the Mayak truss on the Salyut-7 space station, erected May 1986. $\endgroup$ May 11 '21 at 1:59

Updated answer:

  • Mayak (Lighthouse/beacon) or URS truss, mounted on Salyut-7 in May 1986.

Unfortunately, it is not the Sofora Arm, but the predecessor to it.

From EVA's carried out from May 28 1986 to May 31 1986, Cosmonauts Leonid Kizim and Vladimir Soloviyov installed the URS (also known as Mayak) truss on the front compartment of the station, after removing previous experiments.

mayak lighthouse

It is described here:


The cosmonauts then attached the cylindrical 150kg URS space assembly device to the hull outside the airlock hatch. The URS device deployed a 20kg, 12-to-15-m tubular metal truss held together by hinges and springs. URS was designed and built by the Paton Institute of Electric Welding in Kiev.

Further descriptions are:

The assembly unit was a rather large 150-kilogram cylindrical container, where a sliding hinge-lattice structure made of aluminium and titanium was laid. It could be pulled out of the "barrel" manually, in a semi-automatic mode and completely without human intervention using an electric motor. A small orange beacon glowed on top of it

A displacement sensor was mounted to record vibrations

Its upper end swayed noticeably. However, this did not frighten the commander, who decided to subject the mast to an unplanned test. Turning his hands over the steps of the staircase directed into space, swaying his whole body, Kizim slowly climbed higher and higher.

After this the experiment was considered over and the truss was disassembled.

This probably accounts for the scarcity of photos and descriptions.

salyut-7 lighthouse kosmos1686 soyuzt15

As you can see, the installation position accounts for the limb position in the currently only known photograph of the truss.


The extended space station configuration of Salyut-7, with TKS craft Kosmos 1686 permanently docked, from October 1985 to February 1991.

That aside, the physical description shows the ancestry of the two trusses that ended up on Mir.

So, for those reasons, I think I should not delete all the info below, it is still useful.

Incidentally, this also describes the second time ever that welding was carried out in space, using the same hand held URI device that Svetlana Savitskaya used for the first time in 1984 (First female EVA and first welding in space, outside a spacecraft).

  • Information below is for the Sofora truss mounted on Mir.

(At the end I note my interest in pursuing this question)

The description for it is that it is made of titanium nickel - each section 500 x 500 mm, each horizontal section is flat welded with holes for each of the Y sections to go through. I think the truss overall was about 21 sections, made up from a flat pack of 80 pieces.

You can also see the flat corner sections, and the cable that snakes its way down the truss.


It is not the left truss as this is the Rapana arm added in 1993, which is much shorter, and being a test for construction for Mir-2, it is a series of hinged boxes that open out, made of carbon fiber.

![rapana unboxed

Its construction is entirely different from the Sofora arm.

With reference to the @GordonD answer and @OrganicMarble comment, with the Mir photo, taken in 1998:

The truss seen to the right, is not a truss at all, it is just a funny angle of the solar panel mounted on top of Mir.

Either side of that are the Strella cranes.


Laborious construction of the Sofora arm by cosmonauts from flatpacks.

and finally, a really good closer photo of the two truss assemblies.

rapana and sofora truss


  • edit:

Reason for update - even after I had finished the answer something still bugged me and I disliked the lower half of the lattice mast - it did not match the close up photo of Mir.

So I looked closer and realised that there was a record of a previous truss, and it was not on Mir.

Then I re-read the OP article, and it specifically mentions Salyut-7.

Then I read the article on http://www.spacefacts.de and I realised I had to update this answer for clarity and the correct answer.

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    $\begingroup$ Great supplemental info! I found a nice picture that confirms "The truss seen to the right, is not a truss at all, it is just a funny angle of the solar panel mounted on top of Mir." nasa.gov/sites/default/files/thumbnails/image/… $\endgroup$ May 10 '21 at 14:02
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    $\begingroup$ I never thought it was the Sofora, hence my comment to the other answer. Nice detective work! $\endgroup$ May 11 '21 at 3:25
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    $\begingroup$ Yeah, it kept gnawing at me! It was something that existed for only a short time, with only 2 crew members present and very little documentation. $\endgroup$ May 11 '21 at 3:30
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    $\begingroup$ This is getting more and more interesting, thanks! $\endgroup$
    – uhoh
    May 11 '21 at 5:02
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    $\begingroup$ Damn, just when I thought I had finally managed to answer a question here! I'll have to keep trying... $\endgroup$
    – GordonD
    May 11 '21 at 8:17

I believe that's the Sofora girder which was made up of 20 segments totalling 14 metres in length. There was an RCS thruster at the top end which made it easier to orient the station and used less propellant. It was assembled by Anatoli Artsebarsky and Sergei Krikalev during four EVAs in July 1991 and the thruster pack installed by Sergei Avdeyev and Anatoli Solovyov in September 1992. Here's a photo of Mir taken from STS-89 showing the truss with the RCS unit at the top and a manipulator crane to the left.

enter image description here

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    $\begingroup$ An overall picture or diagram of the station showing the truss in context would really help this answer. $\endgroup$ May 9 '21 at 13:10
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    $\begingroup$ Link to picture added as requested! $\endgroup$
    – GordonD
    May 9 '21 at 14:48
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    $\begingroup$ Great! I edited the answer to show the picture instead of the link. In the future you can do that using the little image icon in the editing window. Now, I see three long trusses on Mir. How do you know the one in the question is the one with the RCS on it? To me the structure at the tip looks more like the mast closest to the main juncture of the modules. I don't see the big rectangular box in the picture in the question. $\endgroup$ May 9 '21 at 15:31
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    $\begingroup$ Thanks for embedding the picture; I wasn't sure how to do it. The Sofora is mounted on the Kvant module which is the one on the left to which the Soyuz is docked. The box at the top holds the RCS unit and might not have been attached at the time the photo in the original question was taken - as I said it was more than a year before this was installed. The structure in the question photo looks (to me) too big to be either of the other two. $\endgroup$
    – GordonD
    May 9 '21 at 16:22
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    $\begingroup$ @OrganicMarble your question about the "third truss" is addressed in the new answer. $\endgroup$
    – uhoh
    May 10 '21 at 3:25

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