The space station contains three PMAs. They are used to connect spacecraft and modules with different docking mechanisms.

The space station’s newest piece, the Harmony module (Node 2), was delivered to the International Space Station by the STS-120 Discovery crew.

The PMA-2 is a 1.5-ton cone-shaped docking port. It is the only PMA that contains the Station-to-Shuttle Power Transfer System (SSPTS), which allows a space shuttle mission to remain at the space station longer because it uses power from the station, rather than from the shuttle.

The next move, scheduled for Wednesday, November 14, 2007, is to again use the Canadarm2 robotic arm to move the 16-ton Harmony module and its attached PMA-2 docking port to its final position at the forward hatch of the Destiny laboratory.

In other words, Destiny will be positioned closest to space station, followed by Harmony, and at the end will be PMA-2, which will allow space shuttles and other spacecraft to dock to the space station. A space shuttle, for instance, will approach the PMA-2 at about 0.1 foot per second. When it makes contact with the PMA-2, it will automatically latch onto the shuttle.

Then, on Tuesday, November 20 and Saturday, November 24, 2007, two spacewalks are scheduled that are dedicated to hooking up lines for data, cooling, and power onto the Harmony module.

In unison with the space station activities, NASA is preparing the space shuttle Atlantis for its scheduled December 6, 2007 liftoff.