May 27, 2015
— The International Space Station now has a newly-vacated parking spot, thanks to the relocation of a supply closet to another port on the orbiting outpost.
The move of the Permanent Multipurpose Module (PMM) on Wednesday morning (May 27), marked the first major remodeling of the station in four years and advanced plans to accommodate Boeing and SpaceX commercial crewed spacecraft at the complex beginning in 2017.
Flight controllers, working from NASA's Mission Control in Houston, commanded the station's robotic arm to carefully maneuver the 11-ton PMM – also called "Leonardo" – from its original location on the Earth-facing side of Unity Node 1 to the forward port on Tranquility Node 3.
Space Station commander Terry Virts and flight engineer Scott Kelly oversaw both the unbolting of the PMM earlier in the day and its final attachment at 8:08 a.m. CDT (1308 GMT). The 22-foot-long (6.7 m) module's relocation began at 4:50 a.m. CDT (0950 GMT).
NASA graphic showing the original location of the PMM (in blue) and its new position (in green) onboard the space station. (NASA)
Virts and Kelly, both NASA astronauts and Expedition 43 crew members, closed the hatch leading into to the PMM on Tuesday. They are scheduled to reopen the module on Thursday to begin setting it up for use in its new location.
"We will run some ventilation lines, power lines, data lines [and] some cables to allow us to talk to the [module] in its new location," stated Kenny Todd, ISS mission operations integration manager, in a NASA interview on Tuesday.
Currently, cargo vehicles, including SpaceX's Dragon, the HTV from Japan and Orbital ATK's Cygnus, are berthed to the Earth-facing, or nadir, port on Harmony Node 2. Before the move on Tuesday, the freighters' back-up location was Harmony's space-facing, or zenith, port.
By freeing Unity's nadir port of the PMM to serve as a new parking spot for cargo vehicles, Harmony's zenith port can now be repurposed for crewed spacecraft to use. A similar robotics operation targeted for later this year will relocate a pressurized mating adapter to the Node 2 port for its new role.
The Permanent Multipurpose Module, as it was seen shortly after its original installation on the Unity node in March 2011. (NASA)
Harmony's forward port will also be used by Boeing's CST-100 and SpaceX's Dragon spacecraft when they start to fly astronauts to and from the station in the coming years. Both Node 2 ports will be equipped with new international docking adapters, the first of which is set for delivery on a SpaceX Cargo Dragon in June.
The PMM was originally designed as one of three logistics modules that were used to haul supplies back and forth to the station by the space shuttle. Modified to stay on orbit, the PMM was launched for the last time on STS-133, the final flight of the shuttle Discovery, on Feb. 24, 2011, and was installed on Unity five days later.
Primarily used to store spares and supplies, the PMM has an internal volume roughly the same as a two-car garage.