On a recent visit to Edwards AFB I had a good opportunity to photograph up-close NASA’s stalwart pair of Boeing 747 Shuttle Carrier Aircraft (SCA). The agency’s first aircraft, pictured below, is one of the oldest 747-100 models still active (line No.86) and was delivered to American Airlines in 1970, the type’s first full year of production. Four years later it was acquired by NASA in the build-up to the start of Shuttle operations and release tests of the Enterprise later that decade.
No, not a mythical 747 twin conversion. This is NASA's first 747SCA, temporarily shorn of its outboard P&W JT9D engines. (All photos Guy Norris)
The second SCA is a former Japan Air Lines 747-100SR, distinguished by five upper-deck cabin windows on each side against just three for the early -100s. Structurally beefed-up for the high duty cycle of the shorter domestic routes flown by JAL, the -100SR was acquired by NASA in 1988. The aircraft was first used in 1991 to ferry the Shuttle Endeavour from Rockwell’s (now Boeing) Palmdale, Calif. production site to Kennedy Space Center, Florida.
The relatively young 747-100SR-based SCA, acquired 14 years after the first Shuttle carrier.
..and here is some SCA trivia: Both aircraft are maintained for continued SCA duties, and are flown at a minimum of 45 day intervals to maintain systems integrity and crew proficiency.
On Shuttle ferry flight, the aircraft carries almost 5 tons of forward ballast to offset the center of gravity imbalance caused by the tail-heavy Orbiter. The SCA carries nearly 2 tons of pig iron up-front in the former first class section, and 3.5 tons of pea gravel in the cargo hold.
…and if you look really closely at the aft attachment on the oldest SCA you’ll notice some very small writing which says (in typically technical NASA fashion): "Attach Orbiter Here - Black Side Down."
Check out the mighty SCA/Shuttle combo in action (below).