Hubble Space Telescope by the time it was due to be observed. Engineering support for HST is provided by NASA and contractor personnel at the Goddard Space Flight Center in Greenbelt, Maryland, south of the STScI. Hubble's operation is monitored 24 hours per day by four teams of flight controllers who make up Hubble's Flight Operations Team. By early 1986, the planned launch date of October that year looked feasible, but the "Challenger" accident brought the U.S. space program to a halt, grounding the Space Shuttle fleet and forcing the launch of Hubble to be postponed for several years. The telescope had to
Space Shuttle program from the back of a specially modified Boeing 747, only for initial atmospheric landing tests (ALT). "Enterprise"'s first test flight was on February 18, 1977, only five years after the Shuttle program was formally initiated; leading to the launch of the first space-worthy shuttle "Columbia" on April 12, 1981 on STS-1. The Space Shuttle program finished with its last mission, STS-135 flown by "Atlantis", in July 2011, retiring the final Shuttle in the fleet. The Space Shuttle program formally ended on August 31, 2011. Before the Apollo 11 moon landing in 1969, NASA began early studies of space shuttle designs.