The Progress is a Russian expendable freighter spacecraft. The spacecraft is an unmanned resupply spacecraft during its flight but upon docking with a space station, it allows astronauts inside, hence it is classified manned by the manufacturer. It was derived from the Soyuz spacecraft, and is launched with the Soyuz rocket. It is currently used to supply the International Space Station, but was originally used to supply Soviet space stations for many years. There are three to four flights of the Progress spacecraft to the ISS per year. Each spacecraft remains docked until shortly before the new one, or a Soyuz arrives. Then it is filled with waste, disconnected, deorbited, and destroyed in the atmosphere. Because of the different Progress variants used for ISS, NASA uses its own nomenclature where "ISS 1P" means the first Progress spacecraft to ISS.