Touchdown - NASA 911, one of two modified Boeing 747s that were modified for use as Shuttle Carrier Aircraft for the space shuttles, lands at Air Force Plant 42 in Palmdale Feb. 8 after its final flight, a short hop from NASA's Dryden Flight Research Center at Edwards Air Force Base. (NASA /Tony Landis)› View Larger Image

Jeff Moultrie, Bob Zimmerman and Henry Taylor, (left to right) of Johnson Space Center's Aircraft Operations Directorate took a brief moment for the photographer in the flight deck of NASA Shuttle Carrier Aircraft 911 after crewing its final flight, a brief ferry from NASA's Dryden Flight Research Center at Edwards Air Force Base to the Dryden Aircraft Operations Facility adjacent to Air Force Plant 42 in Palmdale. (NASA / Tony Landis) › View Larger Image One of NASA's two modified Boeing 747s that were modified for use as space shuttle carrier aircraft, NASA 911, made its final flight Feb. 8. The big four-engine converted jumbo jet's final mission was a short flight lasting only about 20 minutes from NASA's Dryden Flight Research Center at Edwards Air Force Base to The Dryden Aircraft Operations Facility adjacent to Air Force Plant 42 in Palmdale.

The converted jetliner will be retired and initially become a source of parts to keep the remaining Shuttle Carrier Aircraft, NASA 905, flying until the three remaining space shuttles have been ferried to the cities of their final display venues. Those sites include the National Air and Space Museum's Udvar-Hazy Center near Washington, D.C. (Discovery), the Intrepid Sea, Air and Space Museum in New York City (Enterprise), the California Science Center in Los Angeles (Endeavour) and the visitor center at NASA's Kennedy Space Center in Florida (Atlantis).

After those deliveries are completed, both shuttle carrier aircraft, which are currently owned by NASA's Johnson Space Center, will be used as a source of spare parts to support NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) Boeing 747SP aircraft flying.

NASA 911, a Boeing 747-100SR short-range version, was the second Shuttle Carrier Aircraft. It was built in November 1973 and was flown in commercial airline service by Japan Air Lines for about 15 years. It was obtained by NASA in 1989 and after modifications by The Boeing Co., it was delivered to NASA on Nov. 20, 1990 to serve as a carrier aircraft for the space shuttles for the next 21 years.

"There was a lot of work that went into the initial design of how to modify the airplane, how to attach (the shuttle to) it, what could you do, how would it fly, what precautions (you had to take) and things like that," reflected Henry Taylor of the Johnson Space Center, who served as flight engineer for many of the shuttle ferry flights, including the last flight of NASA 911. "It just goes to show what American ingenuity can do."

NASA 911 amassed 33,004.1 flight hours over its more than 38-year flying career. That includes 386 flights after it was converted to a shuttle carrier aircraft, including 66 flights carrying a space shuttle on a ferry flight.