Pressurized Mating Adapter
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The International Space Station (ISS) uses three Pressurized Mating Adapters (PMAs) to interconnect spacecraft and modules with different docking mechanisms. The first two PMAs were launched with the Unity module aboard STS-88. The third was launched aboard STS-92.
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[edit] Uses
Each PMA on the ISS is used slightly differently, but all three perform the same basic function of connecting a Common Berthing Mechanism (CBM) port of an ISS module to the Androgynous Peripheral Attach System (APAS) docking port of another module or visiting spacecraft.[1] For this the PMAs carry a passive CBM port and a passive APAS port. They are pressurized and heated from the inside, and through docking rings as well as external connections allow for power and data communications transfer.[2]
[edit] PMA-1
This was one of the first components of the International Space Station and joins the Russian side of the station with the US side. On STS-88 the crew used the shuttle's robotic arm to attach the Zarya control module to PMA-1, which was already connected to the aft berthing port of Unity. PMA-1 now permanently connects these first two station components.
[edit] PMA-2
PMA-2 is currently mounted on the forward port of the Harmony connecting node and used when Space Shuttle orbiters dock at the station. It is the only PMA that has been outfitted with Station-to-Shuttle Power Transfer System (SSPTS) hardware, which allows shuttles to stay docked longer to the space station.[3]
Due to space station assembly PMA-2 has been moved several times. It was originally connected to the forward hatch of Unity, but when STS-98 delivered the Destiny in February of 2001, Destiny was berthed to that hatch while PMA-2 was moved to the forward hatch of the Z1 truss. It was finally moved to the forward hatch of "Destiny". [4] (The removal of PMA-2 from Unity was the first time the Common Berthing Mechanism (CBM) was used to disconnect two ISS components.[5]) After STS-120 had delivered Harmony at the station in October 2007, Canadarm2 relocated PMA-2 to its final location at the forward hatch of Harmony on November 12, 2007. Two days later, the combined package of Harmony and PMA-2 was moved to its final location, the forward hatch of Destiny. PMA-2 will stay berthed at the forward port of Harmony for the remaining duration of the ISS.
When a shuttle docks with the station, its "final approach [is] at a relative velocity of one-tenth of a foot per second. [As it] makes contact with Pressurized Mating Adapter 2 [latches] automatically attach the two spacecraft together. Once relative motion between the spacecraft stops, [a shuttle astronaut] retracts the docking ring on [the shuttle's] mechanism, closing latches to firmly secure the shuttle to the station."[6])
[edit] PMA-3
In October of 2000 STS-92 brought PMA-3, mounted on a Spacelab pallet, to the station.[7] It was initially attached to the nadir (bottom, or Earth-facing) hatch of Unity. One and a half months later, when STS-97 delivered the P6 solar array truss structure, Endeavour docked at PMA-3.[8] Also, when STS-98 moved PMA-2 from Unity to Destiny, Atlantis was docked at PMA-3.[4] PMA-3 was moved in March of 2001 to Unity's port hatch by the crew of STS-102 to make room for the docking of a Multi-Purpose Logistics Module (MPLM).[9] On August 30, 2007 PMA-3 was moved to the nadir hatch of Unity to make room for the temporary docking of the Harmony module that was delivered by STS-120.[10]) Its final location will be the nadir hatch of Node 3 when this will be berthed to Unity, a configuration scheduled for 2010. While Node 3 is being added to ISS, PMA-3 will be temporarily docked to the nadir port of Harmony.
[edit] History
Pressurized Mating Adapters were constructed by Boeing, as was a similar adapter which allowed the U.S. Space Shuttle to dock with Russia's Mir space station.[11]
[edit] See also
[edit] References
- ^ Human Space Flight - Space Fact. NASA (04/07/2002). Retrieved on 2007-01-17.
- ^ STS-92 Press Release Kit: Payload section. NASA (10/10/2000). Retrieved on 2007-10-27.
- ^ International Space Station Status Report #07-08. NASA.
- ^ a b STS-98, Mission Control Center (February 10, 2001). Status Report # 07. NASA. Retrieved on 2007-01-18.
- ^ Harwood, William (February 10, 2001). Atlantis crew to attach Destiny lab to station today. Spaceflight Now. Retrieved on 2007-01-15.
- ^ STS-102, Mission Control Center (March 9, 2001). Status Report # 03. NASA. Retrieved on 2007-01-18.
- ^ STS-92, Mission Control Center (October 16, 2000). Status Report # 10. NASA. Retrieved on 2007-01-18.
- ^ STS-97, Mission Control Center (Dec. 2, 2000). Status Report # 05. NASA. Retrieved on 2007-01-18.
- ^ STS-102, Mission Control Center (March 11, 2001). Status Report # 07. NASA. Retrieved on 2007-01-18.
- ^ SHUTTLE/SOYUZ/ISS PROCESSING MILESTONES. CBS News.
- ^ Boeing: Integrated Defense Systems - NASA Systems - International Space Station - Pressurized Mating Adapters
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