Mir Docking Module - Development

Development

The docking module originated in the 1992 design version of the cancelled Mir-2 space station, which featured a combined docking compartment and airlock to facilitate docking missions during the Soviet Buran space shuttle programme (this module, SO-1, was eventually incorporated into the Russian Orbital Segment of the International Space Station as Pirs). When the Shuttle-Mir programme began, engineers realised that in order to enable US space shuttles to dock to Mir, the Kristall module would have to be relocated to the forward port of the core 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 on Kristall's Lyappa arm, which, should it fail, would prevent any further shuttle missions to the station. Adding a small extension to Kristall, 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 the Mir-2 docking compartment.

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 two Soyuz TM-16 type Soyuz orbital modules cut in half, with a cylindrical central portion mounted in the centre of the two halves which incorporated docking apparatus (the other two halves were not used). An APAS-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. Development of the simplified module was given priority over the more complex Mir-2 type SO-1, and the flight model, the first to make use of NASA's new Space Station Processing Facility, was delivered to Kennedy Space Centre on 7 June 1995 alongside the new solar arrays which were to be launched with it.

The module was launched aboard the Space Shuttle Atlantis on 12 November 1995 on mission STS-74 and both the module and Atlantis docked to Mir on 15 November, leaving STS-71 as the only Shuttle-Mir docking mission requiring Kristall to be relocated.