The evolution of manned space avionics

The avionic systems considered in the present paper are related to flight controls, communications, navigation, guidance, displays, and instrumentation. The beginning of manned space avionics can be traced to the simple analog system installed in the X-15. The evolution of manned space avionics led finally to the systems of the Space Shuttle when the technology of fault-tolerant electronics permitted an unpowered spacecraft to make an assured landing at a preselected airfield. The relative position of the U.S. to the Soviet Union with respect to manned space avionics underwent changes during this evolution. Throughout the early 1960s, the Soviet Union had a slight lead over the U.S., while in the late 1960s the Apollo program led to a commanding lead of the U.S. An elaborate Soviet space station program in the 1970s resulted in significant gains for the Soviet Union. Forecasts regarding a number of trends in manned space avionics are also provided, taking into account also a permanent lunar base.