PAYLOAD DEPLOYMENT AND RETRIEVAL

For satellite deployment missions Buran would have been equipped with an extend­able turntable that would first lift the payload out of the confines of the cargo bay. After deploying the payload’s appendages and checking all on-board systems, the satellite would then have been spun up and released with the help of springs.

Buran was also supposed to be outfitted with a robotic arm system to deploy and retrieve payloads. One of its primary tasks would have been to lift space station modules out of the vehicle’s cargo bay and attach them to available docking ports and also to provide a stable platform for spacewalking cosmonauts. Developed by the Central Scientific Research Institute of Robotic Technology and Technical Cyber­netics (TsNII RTK) in Leningrad, the so-called On-Board Manipulator System (SBM) was similar in design to the Shuttle’s Canadian-built Remote Manipulator System (RMS). Measuring 15m and weighing 360 kg, it had six joints and could lift a payload of up to 30 tons. Maximum translation speed was 30 cm per second without a payload and 10 cm per second with a payload. The SBM would be operated manually from a console in the aft flight deck with two joysticks, one to move the arm itself, and

the other to operate the grapple fixture. Three cameras, one on the wrist and two in the cargo bay, would have assisted in these operations. It was also possible to operate the arm automatically using software stored in the on-board computer. During unmanned missions the arm could even have been controlled from Mission Control via the on-board computer system. With the Shuttle never having been designed to fly unmanned, the RMS did not provide that capability, although the technique was later introduced for the International Space Station’s Remote Manipulator System (SSRMS), which was first remotely operated from the ground in March 2006.

The major difference with the RMS was that even on standard missions Buran would have carried two arms, one on the left, the other on the right longeron to provide more flexibility in loading/unloading operations or provide back-up cap­ability. Although provisions for two arms were incorporated in each Space Shuttle Orbiter, the idea of ever flying two RMS units on a single Orbiter was abandoned in the late 1990s. After the 2003 Columbia accident the remaining Shuttle Orbiters were equipped with a second arm known as the Orbiter Boom Sensor System, but this is solely intended to make camera surveys of RCC panels and heat shield tiles.

The SBM was not flown on Buran’s only mission in November 1988, but was supposed to be installed on the second flight vehicle for a docking mission with the

Mir space station. A working model of the arm was built and installed at TsNII RTK on a special test stand capable of simulating weightless conditions [26].