A wet workshop is a space station made from a spent liquid-propellant rocket stage. Such a rocket stage contains two large, airtight propellant tanks; it was realized that the larger tank could be retrofit into the living quarters of a space station, while the smaller one could be used for the storage of waste. A large rocket stage would reach a low Earth orbit and undergo later modification. This would make for a cost-effective reuse of hardware that would otherwise have no further purpose, but the in-orbit modification of the rocket stage could prove difficult and expensive. , no wet-workshop space station has been built or flown.