Progress cargo spacecraft

In place of a descent module Progress carries a refuelling compartment: fuel and oxidiser tanks are pumped into the station's own tanks through lines after docking. That solution extended the life of the Salyut stations and Mir from months to years. The ship is expendable: after unloading it is filled with waste and deorbited over the Pacific. More than 170 flights have been made in over forty years; Progress vehicles also tested new rendezvous profiles, including the two-orbit approach. On display is a full-scale engineering mock-up with the solar arrays deployed.