Complex sentence: HES research was funded by IBM but the program was stopped around 1969 and the program was reportedly used by NASA's Houston Manned Spacecraft Center, which was used the program for documentation on the Apollo space program (van Dam, 1988).
Split into simpler sentences: HES research was funded by IBM but the program was stopped around 1969. The program was used by NASA's Houston Manned Spacecraft Center for documentation on the Apollo space program (van Dam, 1988).