Pressurized Mating Adapter

From Wikipedia, the free encyclopedia

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.

Contents 1 Uses 1.1 First station components connected using PMA-1 1.2 Shuttle docking at PMA-2 1.3 PMA-3 2 History 3 See also 4 References

[edit] Uses

Each PMA on the ISS is used slightly differently.

[edit] First station components connected using PMA-1

Using the shuttle's robotic arm the STS-88 crew attached the Zarya 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] Shuttle docking at PMA-2

PMA-2 is currently used when Space Shuttle orbiters dock at the station. It was originally connected to the forward hatch of Unity, but when STS-98 delivered the Destiny Laboratory Module in February of 2001, Destiny was berthed to that hatch and PMA-2 was berthed to the forward hatch of Destiny.^[1] (The removal of PMA-2 from Unity was the first time the Common Berthing Mechanism, or CBM, was used to disconnect two ISS components.^[2]) Harmony (formerly known as Node 2) is scheduled to arrive at the station on STS-120, no earlier than September 2007. When it arrives the orbiter will dock at PMA-2. Then the SSRMS will move Node 2 from the orbiter cargo bay to a temporary location at the port hatch of Unity. After the orbiter departs, the SSRMS will berth PMA-2 to the forward hatch of Node 2. It will then move the two components together to their final location, forward of Destiny.

PMA-1 and PMA-2 both use the Androgynous Peripheral Attach System to dock with the other spacecraft.^[3] 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."^[4])

[edit] PMA-3

In October of 2000 STS-92 brought PMA-3, mounted on a Spacelab pallet, to the station.^[5] 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.^[6] Also, when STS-98 moved PMA-2 from Unity to Destiny, Atlantis was docked at PMA-3.^[1] PMA-3 will be moved to its final location once Node 3 is berthed to Unity.

[edit] History

Pressurized Mating Adapters are Boeing products, as was a similar adapter which allowed the U.S. Space Shuttle to dock with Russia's Mir space station.^[7]

[edit] See also

• ISS assembly sequence

[edit] References

1. ^ ^{a b} STS-98, Mission Control Center (February 10, 2001). Status Report # 07 (html). NASA. Retrieved on 18 January 2007.
2. ^ Harwood, William (February 10, 2001). Atlantis crew to attach Destiny lab to station today (html). Spaceflight Now. Retrieved on 15 January 2007.
3. ^ Human Space Flight - Space Fact (html). NASA (04/07/2002). Retrieved on 17 January 2007.
4. ^ STS-102, Mission Control Center (March 9, 2001). Status Report # 03 (html). NASA. Retrieved on 18 January 2007.
5. ^ STS-92, Mission Control Center (October 16, 2000). Status Report # 10 (html). NASA. Retrieved on 18 January 2007.
6. ^ STS-97, Mission Control Center (Dec. 2, 2000). Status Report # 05 (html). NASA. Retrieved on 18 January 2007.
7. ^ [1]