Converting an MPLM to a PMM

The Multi-Purpose Logistics Module (MPLM) are pressurized modules for transporting equipment, supplies and experimental devices to and from the International Space Station (ISS). An MPLM is carried in the cargo bay of a Shuttle and attached to the Unity or Harmony modules on the ISS for the duration of a mission, usually about 10 days. From there, supplies are offloaded, and finished experiments and waste are reloaded. The MPLM is then returned to the Space Shuttle payload bay for return to Earth. Three modules were built, Leonardo, Raffaello and Donatello. The modules were provided to NASA under contract by the Italian Space Agency. Each MPLM was built to be on-orbit a maximum of one month at a time. The MPLM Leonardo is being modified to turn it into the Pressurized Multipurpose Module (PMM), which will remain permanently attached to the ISS following the STS- 133 mission. The Space Shuttle is the only vehicle or rocket that has the capacity to carry the MPLM to the ISS. With the planned retirement of the Space Shuttle in 2011, NASA has found another use for the MPLM. With the modifications of the MPLM into a PMM the ISS will have another permanent module as part of the ISS that will be used as a storage module