Progress-M1 (Russian: Прогресс-М1, GRAU indices 11F615A55 and 11F615A70), also known as Progress 7K-TGM1, is a Russian spacecraft which is used to resupply space stations. It is a variant of the Progress spacecraft, derived from the Progress-M, but modified to carry more propellant for refuelling the space station instead of other cargoes such as water. A Progress M1 11F615A55 spacecraft could carry 1,700 kilograms (3,700 lb) of propellant, compared to the 850 kilograms (1,870 lb) that a Progress-M of the same generation could carry.