Orbital operations

Like the Space Shuttle Orbiter, Buran was a versatile vehicle that could have been used for a wide range of orbital operations. The following possible tasks were later identified by the Russians:

(a) Deployment of satellites or other cargos: the maximum payload was 30 tons into a 50.7° inclination 200 km orbit and 16 tons into a 97° orbit. The payload bay could house a payload with a maximum length of 15 m and a maximum diameter of 4.15 m. Because of the less stringent center-of-gravity requirements resulting from the absence of main engines, Buran’s maximum payload capacity was actually higher than that of the Space Shuttle.

(b) Servicing satellites in orbit

(c) Returning satellites back to Earth. The maximum mass that could be returned from a 50.7° inclination 200 km orbit was 20 tons.

(d) Space station missions: resupply, assembly, crew exchange, crew rescue.

(e) Missions to assemble large structures in space.

(f) Autonomous scientific missions.

Three basic types of operational mission durations were envisaged for the vehicle. The first would be short-duration missions (up to 3 days) to place heavy payloads into orbit, deliver emergency supplies to space stations, or rescue space station crews. Such missions would be characterized by multiple operations and maneuvers in a relatively short time span, heavily taxing both the crew and the ground and also requiring many of them to be conducted automatically.

Medium-duration missions (up to 8 days) were expected to be the most frequent ones and would have several objectives or one particularly time-consuming and demanding goal. Typical medium-duration flights would include routine missions to space stations, multiple satellite deployment missions, satellite-servicing missions, assembly flights, etc. Although comparable in the number of operations with the short-duration flights, the longer time in orbit would make it possible to more evenly spread the workload for the crew.

Finally, long-duration missions (9 to 30 days) would primarily be devoted to scientific, materials-processing, and biotechnological experiments, which take a relatively long time to produce the necessary results. For this purpose, the Russians were planning to develop a Spacelab-type module to be placed in the cargo bay. The longest missions would have required the installation of an extra cryo kit for the fuel cells. The number of maneuvers performed during this type of mission would have been very low. In terms of the daily workload for the crew and the ground, such missions would have been comparable with a routine workday on a space station.

Range safety restrictions at the Baykonur cosmodrome, mainly dictated by the impact zones of the strap-on boosters, limited the possible orbital inclinations of the spacecraft to 50.7-83°, 97°, 101-104°, and 110°. The vehicle could have operated at altitudes between 200 and 1,000 km, although the higher of these would have necessitated the installation of extra propellant tanks in the cargo bay [29].