I have to post some information about this calculator because it’s a distant relative of HP calculators: the Elektronika Mk-52. Two noteworthy facts about this model:

Here’s an excerpt from the Museum of Soviet Calculators on the Web:

Soyuz TM-7, 26 November 1988-27 April 1989

Property of Cosmonaut Aleksandr A. Volkov, Elektronika MK-52 Calculator, with 2-part instructional booklet, used for calculating the perimeters of the docking of Soyuz capsules with Mir in the event of the failure of onboard computers. The bottom of the calculator case and the front covers of both parts of the instructional booklet are signed by Volkov with the inclusive dates of the TM-7 mission and also stamped with the Mir ink cancellation.

“…and there was a ROM module with astronomical programs that the cosmonauts in Mir used… of course it was military/restricted, and no one ever saw it!”

Another excerpt, this time from the Soviet Calculators History webpage:

By the way, the MK-52 flew to the space in the “Soyuz TM-7”, where it was supposed to compute the landing trajectory in case the onboard computer would fail.

Soyuz TM-7 launch

Soyuz TM-7 launch

Elektronika Mk-52

Elektronika Mk-52

Mir space station

Mir space station