Heron & Fox

The Androgynous Peripheral Attach System (APAS) on display at the Kennedy Space Center Visitors Complex (KSCVC). APAS was co-developed by Soviet and American engineers as part of a plan to dock an American Apollo spacecraft with a Soviet spacecraft, at first a Salyut station, and ultimately a Soyuz spacecraft. APAS was different from previous docking systems, which had one "active" mechanism on one spacecraft, and one "passive" mechanism on the other spacecraft. Using APAS, either spacecraft can be the active or passive partner. The Apollo-Soyuz Test Project (ASTP), in which an Apollo spacecraft used an APAS adapter to dock to an APAS-equipped Soyuz in orbit. The Soviets continued to work on the APAS system, planning to use it for their reusable Shuttle-like orbiter, Buran, and one module on the Mir station, Kristall, was equipped with two APAS adapters to accommodate Buran. Buran ended up making only one flight under automated control, but the docking system for Buran was moved to the American Space Shuttle so that the Shuttle could dock to Mir, and to prepare for the construction of the coming International Space Station (ISS). The current docking system standard, the International Docking System (IDS) or Low-Impact Docking System (LIDS), is based on APAS.