The original APAS-75 docking unit

Design

APAS was designed by Vladimir Syromyatnikov of the Moscow-based RSC Energia and has roots in the Apollo-Soyuz program.^[4] Russia built 5 Soyuz spacecraft that used APAS-75. The first 3 flew as test systems (Cosmos 638, Cosmos 672 and Soyuz 16). One was used for the Apollo-Soyuz Test Project, Soyuz 19 the only Soyuz to actually use the docking system, and the last one flew as Soyuz 22. On the American side the ASTP Docking Module carried one APAS-75 docking collar and one Apollo docking collar.

APAS-89

When Russia started working on Mir they were also working on the Buran shuttle program. APAS-89 was envisioned to be the docking system for Buran with the Mir space station. The original design was heavily modified. The outer diameter was reduced from 2030 mm to 1550 mm and the alignment petals were pointed inward instead of outward. This limited the internal diameter of the docking port to about 800 mm. The Buran shuttle was finally cancelled in 1994 and never flew to the Mir space station, but Mir's Kristall module was outfitted with two APAS docking collars. When the Shuttle-Mir Program began APAS was selected as the docking system. The visiting US Space Shuttles used a Androgynous Peripheral Attach System docking collar originally designed for Buran, mounted on a bracket originally designed for use with the American Space Station Freedom. The Mir Docking Module, basically a spacer module between Kristall and the Shuttle also used APAS-89 on both sides. This design is sometimes called Androgynous Peripheral Docking System.

APAS-95

Its current design is based on that of the Androgynous Peripheral Docking System used in the Shuttle-Mir Program. The system has an active and a passive side. The active capture ring that extends outward from the orbiter will capture the passive mating ring on the space station's Pressurized Mating Adapters. The capture ring aligns them, pulls them together and deploys 12 structural hooks, latching the two systems with an airtight seal.

Other docking systems

Other docking ports on the Russian station modules use the Russian Probe and Cone Mechanism, which works in a similar way for the docking of Russian spacecraft. The NASA-designed Low Impact Docking System, which is to serve as the main docking system for Project Constellation, is a smaller, lighter, simpler version of APAS, but is not compatible with it.

Images

<gallery widths="250px" heights="250px" perrow="6"> Image:Shuttle Orbital Docking System (ODS) close-up.jpg|Space Shuttle Orbital Docking System close-up Image:APAS-89 docking system drawing.png|APAS-89 androgynous docking unit Image:76p-013-low.jpg|APAS in a Shuttle-Mir docking. </gallery>

References

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