WIKIARCHIVES.SPACE

Discussion of the software problem which delayed the first Shuttle orbital flight.
On April 10, 1981, about 20 minutes prior to the scheduled launching of the first flight of America's Space Transportation System, astronauts and technicians attempted to initialize the software system which "backs-up" the quad-redundant primary software system ......and could not. In fact, there was no possible way, it turns out, that the BFS (Backup Flight Control System) in the fifth onboard computer could have been initialized properly with the PASS (Primary Avionics Software System) already executing in the other four computers