Pressurized mating adapter

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PMA-2 connects to the Unity module (left) in the Kennedy Space Center .

Pressurized Mating Adapter ( PMA , in German for "pressurized connection adapter ") describes a series of three coupling adapters of the International Space Station (ISS) that are used to dock feeder vehicles and as a connection between the American and Russian segments. The adapter PMA-1 is used to connect the Unity connection node to the Sarja module, two further adapters (PMA-2 and PMA-3) were used as docking points for the space shuttle . The canceled Crew Return Vehicle (CRV) and the Orion spaceship , which has meanwhile been planned as a feeder to the ISS, were also to dock at a PMA.

technology

Each conical PMA is made of aluminum, is approximately 2.0 m long and has a mass between 1.6 t (PMA-1) and 1.2 t (PMA-3). Each adapter has a 1.3 m wide American-style CBM ( Common Berthing Mechanism ) coupling socket at one end , which is used in all other US modules of the station, and a laterally offset APAS-95 coupling socket (Androgynous Peripheral Attachment) System) of Russian design with a diameter of 0.7 m for docking the space shuttles or the Sarja module.

The experience gained from the shuttle docking module developed for the Mir space station flowed into the construction of the PMA . On the Mir, the Russian module Kristall used the previous APAS-89 coupling unit , which was intended for the Russian Buran space shuttle. Inside the heated PMAs there is normal air pressure, so that space travelers can move between the individual sections of the ISS or a docked space shuttle in these tunnel-like modules without a space suit . If the PMA is not occupied by spacecraft, the interior is mainly used as a storage room for supplies and equipment that is not required. Various brackets are mounted on the outer skin of the PMAs, which are used to hold smaller components and spare parts for outboard operations.

The adapters were manufactured by Boeing in Huntington Beach ( California ).

PMA-1

First assembly work on the ISS as part of the STS-88 shuttle mission: The US docking node Unity is docked with the PMA-2 on the space shuttle. Opposite Sarja (above) is connected to PMA-1.

PMA-1 was brought to the ISS on December 4, 1998 on the STS-88 mission along with the Unity Liaison Node and PMA-2. Both PMAs were mounted on the Unity module before the start. The Sarja module was connected to the PMA-1 coupling adapter with the robot arm of the space shuttle Endeavor . This makes PMA-1 the link between the US and Russian sections of the ISS.

The Russian Strela-1 crane was temporarily stored at PMA-1 from 1999 .

PMA-2

PMA-2 was attached to the Unity module on the opposite side of PMA-1 before takeoff and was also transported to the ISS with STS-88. It served as a docking point for the space shuttle until 2011.

With the further expansion of the station, PMA-2 was implemented several times. It was first moved to the bow of the US laboratory Destiny on February 12, 2001 during the STS-98 mission , which occupied the previous docking point of PMA-2. The 16th long-term crew of the ISS finally relocated PMA-2 to its final position in November 2007 with the help of the Canadarm2 robotic arm at the bow of the Harmony connection node delivered during the STS-120 mission .

On February 4, 2007, PMA-2 was equipped with the SSPTS ( Station-to-Shuttle Power Transfer System ) lines during an outboard operation. This enabled the US space shuttles to be supplied with energy from the space station and thus to remain connected for longer.

In 2016, the International Docking Adapter (IDA-2) was transported to the ISS as part of the payload of the CRS-9 mission and docked with the Canadarm on the APAS-95 side of the PMA-2 . A space walk was necessary to connect the cables and wires, which took place on August 19, 2016. The adapter turned the APAS-95 coupling nozzle into a coupling nozzle that complies with the newly developed International Docking System Standard . In March 2019, a spaceship - a Dragon 2 - docked there for the first time as part of the SpX-DM1 test mission .

PMA-3

The launch of PMA-3 took place on October 11, 2000 together with the Z1 lattice structure with the STS-92 mission . PMA-3 was installed on the bottom of the Unity module.

A month and a half later, when STS-97 brought the P6 solar cell element, the Endeavor was the first space shuttle to dock with PMA-3. The Atlantis also docked with PMA-3 during the STS-98 mission to enable Unity's PMA-2 docking adapter to be moved to the Destiny laboratory. This was the second and final coupling of a space shuttle to PMA-3.

In March 2001, PMA-3 was relocated to the port side of Unity during the STS-102 mission to make way for the MPLM. On August 30, 2007, the PMA-3 was re-docked to the bottom of Unity to make room for the temporary docking of the Harmony module during the STS-120 mission. On January 25, 2010, PMA-3 was relocated to the top of Harmony in order not to interfere with the docking of Tranquility during the STS-130 mission.

Upon activation of Tranquility, PMA-3 was relocated to its temporary final position on the front of the Tranquility module on February 16, 2010. It remained there as a replacement in the event of a defect in the PMA-2 used for shuttle couplings and also serves as a micrometeorite protection shield for Tranquility.

On March 26, 2017, PMA-3 was finally relocated again to the zenith position of Harmony using Canadarm2. There was IDA-3 attached to the simultaneous docking of two spacecraft of the type CST-100 Star liner and Dragon 2 to enable.

See also

Web links

Commons : Pressurized Mating Adapters  - Collection of images, videos and audio files

Individual evidence

  1. ^ SpaceX conducts second ground landing after launch of CRS-9 Dragon to ISS. Spaceflight insider, July 18, 2016, accessed on May 29, 2017 .
  2. ↑ Spacewalkers attach docking adapter to space station for commercial vehicles. Spaceflight now, August 19, 2016, accessed May 29, 2017 .
  3. ↑ International Space Station PMA-3 docking module relocated. SpaceFlight Insider, accessed March 30, 2017 .