TheMir Docking Module, formally known as theStykovochnyy Otsek (SO;Russian:стыковочный отсек,lit. 'Docking compartment'; designation:316GK), was the sixth module of the Russian space stationMir, launched in November 1995 aboard theSpace ShuttleAtlantis.^[4] The module, built byEnergia, was designed to help simplify space shuttle dockings toMir during theShuttle-Mir program, preventing the need for the periodic relocation of theKristall module necessary for dockings prior to the compartment's arrival.^[3] The module was also used to transport two newphotovoltaic arrays to the station, as a mounting point for external experiments, and as a storage module when not in use for dockings.^[1]

Mir Docking Module

The docking module seen in the payload bay of theSpace ShuttleAtlantis onSTS-74, prior to docking withMir.
Module statistics
Part of	Mir
Launch date	12 November 1995
Launch vehicle	Space ShuttleAtlantis (STS-74)
Docked	15 November 1995
Reentry	23 March 2001
Mass	6,134 kg (13,523 lb)
Length	4.7 m (15 ft)
Diameter	2.2 m (7 ft 3 in)
References:[1][2][3]
Configuration
The docking module shown isolated in its basic configuration. Various additional external fixtures are not shown.

The docking module originated in the 1992 design version of the cancelledMir-2 space station, which featured a combined docking compartment and airlock to facilitate docking missions during the SovietBuran space shuttle programme (this module, SO-1, was eventually incorporated into theRussian Orbital Segment of theInternational Space Station asPirs). When theShuttle-Mir programme began, engineers realised that in order to enable US space shuttles to dock toMir, theKristall module would have to be relocated to the forward port of thecore module and back to its own lateral port each time a shuttle docked, a process which was not only time consuming but would also be entirely reliant onKristall'sLyappa arm, which, should it fail, would prevent any further shuttle missions to the station. Adding a small extension toKristall, however, would provide the shuttles the clearance they needed to dock without necessitating the relocation of the module on each occasion, and it was decided to base the design of the new module loosely on that of theMir-2 docking compartment.^[1]

Discussions on providing a docking module for the Shuttle-Mir programme began in May 1993 and approval was granted on 1 November, with the draft plan being developed by December. The module consisted of what were essentially twoSoyuz TM-16 typeSoyuz orbital modules cut in half, with a cylindrical central portion mounted in the center of the two halves which incorporated docking apparatus (the other two halves were not used). AnAPAS-89 docking port was mounted on each end. Mounting points were also provided for two boxes (containing new solar arrays) and other external experiments, and the module was provided with its own thermal control, television transmission, and telemetry systems. Rather than being covered in a newly-manufactured white thermal blanket, the module was flown with an unusual orange blanket, which was selected from pre-existing stock for financial reasons.^[5] Development of the simplified module was given priority over the more complexMir-2 type SO-1, and the flight model, the first to make use of NASA's newSpace Station Processing Facility, was delivered toKennedy Space Center on 7 June 1995 alongside the new solar arrays which were to be launched with it.^[1]

The module was launched aboard theSpace ShuttleAtlantis on 12 November 1995 on missionSTS-74 and both the module andAtlantis docked toMir on 15 November, leavingSTS-71 as the only Shuttle-Mir docking mission requiringKristall to be relocated.^[6]

The module resembles the pressure hull for the cancelledScience Power Platform intended forMir-2 and theInternational Space Station, the test article for which was turned into theRassvet Mini-Research Module 1 and launched in 2010 aboardAtlantis, on missionSTS-132.

In addition to simplifying space shuttle docking missions,Mir's docking module was also used as a carrier for two newphotovoltaic arrays, mounted to the module in boxes, which were later deployed onKvant-1 during spacewalks. The first, theMir Cooperative Solar Array, was jointly designed byNASA and Russia in order to test designs for the futureInternational Space Station. The array was 42 m² in area, and provided 6.7 kW of power when installed on the station during expeditionEO-21 in 1996.^[2][4] The array consisted of 42 US-built panels arranged in a 2.7 m (9 ft) wide and 18 m (59 ft) long array mounted to a Russian-built frame, and was instrumented to provide data for models being used to design the solar arrays for the ISS.^[7] The second array was the Russian-built MSB array, which had originally been intended to be launched as part ofPriroda before the redesign of the module deleted it.^[1] It was installed onKvant-1 during EVA 5 ofEO-24, replacing theKristall array which had previously been mounted there.^[4]

The module was also used as a mounting point for theMir Environmental Effects Payload (MEEP), a set of four experiments intended to study the effects of space debris impacts and exposure to the space environment on a variety of materials.^[8] The materials used in the experiments were being considered for use on the ISS, and by exposing them at a similar orbital altitude to that flown by the station, the experiments provided an assessment of the performance of those materials in a similar space environment.^[8] MEEP also fulfilled the need to examine the occurrence and effects of man-made debris and naturalmicrometeoroids through capture and impact studies.^[8] The experiments were installed on the docking module duringSTS-76,^[9] and retrieved duringSTS-86.^[10]

• Pirs (ISS module)
• Poisk (ISS module)
• Rassvet (ISS module)