The modified Soyuz TMA manned transport spacecraft has been developed on the basis of a Soyuz TM spacecraft in accordance with intergovernmental agreements between Russia and the USA and is an integral part of the Orbital Station Complex. The main purpose of the manned transport spacecraft is to provide rescue of the main crew of the station and delivery of special visiting crews.
During the flight the spacecraft fulfills the following tasks:

• delivery of a visiting crew consisting of up to three persons and small accompanying cargoes (research equipment, personal affairs of cosmonauts, repair equipment for the station, etc.);
• constant availability of the spacecraft, attached to the station during its manned flight, in the standby mode to be ready for emergency descent of the main crew onto the ground in case of hazardous situation on the station, cosmonaut illness or injury, etc. (assured crew return vehicle function);
• planned descent of the visiting crew onto the ground; the composition of the spacecraft crew during delivery and return may be changed on the station;
• returning to the ground, together with the crew, payloads of relatively low mass and volume (results of crew work on the station, personal affairs, etc.);
• disposal of wastes from the station in the living compartment to be burned down in the atmosphere during descent.

Modified Vehicle Soyuz TMA Overall View	Modified Vehicle Soyuz TMA Layout