While Endeavour is the star as it travels the West to its retirement home in Los Angeles, the 2 747s which ferried the shuttles from landing bases to Florida have played an amazing role in the NASA program.
“Features that distinguish the two SCAs from standard 747 jetliners are:
- Three struts with associated interior structural strengthening protrude from the top of the fuselage (two aft, one forward) on which the orbiter is attached.
- Two additional vertical stabilizers, one on each end of the standard horizontal stabilizer, to enhance directional stability.
- Removal of all interior furnishings and equipment aft of the forward No. 1 doors.
- Instrumentation used by SCA flight crews and engineers to monitor orbiter electrical loads during the ferry flights and also during pre- and post-ferry flight operations.
NASA 905 was the first SCA. It was obtained from American Airlines in 1974. Shortly after acceptance by NASA, the SCA flew a series of wake vortex research flights at the Dryden Flight Research Center, Edwards, Calif., in a study to seek ways of reducing turbulence produced by large aircraft. Pilots flying as much as several miles behind large aircraft have encountered wake turbulence that has caused control problems. The NASA study helped the Federal Aviation Administration modify flight procedures for commercial aircraft during airport approaches and departures. Following the wake vortex studies, NASA 905 was modified by Boeing to its present SCA configuration.”
Photo Credit Space.com of a Shuttle being piggybacked on a SCA