World’s Largest Piggyback Ride!

Two Jumbo Jets as the Shuttle Carrier Aircraft 

By NASA – Kennedy Space Center image archive, Public Domain, https://commons.wikimedia.org/w/index.php?curid=30115847

The Space Shuttle Program continued for almost 30 years, starting in 1981 with the STS-1 mission and ending in 2011 with the STS-135 mission. A total number of 135 missions have been flown with five shuttles: Columbia, Challenger, Discovery, Atlantis, and Endeavor. Two shuttles were completely lost during two missions killing all astronauts on board. 

A shuttle named Enterprise was the first orbiter to be built and used for Approach and Landing Tests (ALT). However, it never flew into space. 

Kennedy Space Center (KSC) in Florida was the launch site for all the missions while 78 landings were performed in Kennedy Space Center, in the meantime, Edwards Air Force Base handled 54 landings, and a single landing was performed in White Sands, Mexico. 

To be precise, the space shuttle is the term used for the entire vehicle, while the aircraft-shaped vehicle is the Orbiter Vehicle (OV). The orange color external fuel tanks were not recoverable as it burns in the atmospheric re-entry. The white color Solid Rocket Boosters were recovered for later use. 

Orbiter Vehicle spends most of the time in Orbiter Processing Facility (OPF) getting ready for the next mission. When the Orbiter Vehicle landed in a place other than Kennedy Space Center, it requires to be transported back to the KSC. Here comes the mighty Shuttle Carrier Aircraft (SCA) into the action. 

How Many Shuttle Carrier Aircraft Were There? 

There were two of them specially designed to piggyback the space shuttle. SCA N905, a B747-123 model that was built in 1970 and flew under American Airlines joined with NASA in 1974. NASA obtained the other SCA, N911 in 1990 from Japan Airlines. 

What Were the Major Differences? 

Both the SCAs were initially built by Boeing as usual commercial jets and later modified to piggyback the shuttles. Boeing undertook the modifications of both the aircraft and had to undergo extensive modifications improving the sturdiness to support the shuttle which was weighing somewhere around 75 tonnes. 

The Orbiter Vehicle was mounted to struts bolstered to the B747 fuselage. Due to the high weight and unusual shape, a pair of vertical stabilizers were added to the horizontal stabilizer to regain the lost stability.  A mate-demate device was used to piggyback the Orbiter Vehicle to and from the SCA. 

Apart from the widely known piggyback rides, the first shuttle carrier aircraft was used for the launch of the Enterprise shuttle amidst the test flights. As shuttle Enterprise was not fitted with any engines, SCA piggybacked the shuttle to the required altitude.  

Where are Shuttle Carrier Aircraft now?

Both the SCAs retired one year later with the discontinuation of the space shuttle program. SCA N911 flew to Dryden Flight Research Facility in California marking its final mission and resting in the Joe Davies Heritage Airpark in Palmdale, California. The other SCA coded N905 flew its final missions ferrying the retired space shuttles to the museums and marked its retirement after flying to Los Angeles International Airport carrying the space shuttle Endeavor. Now, SCA N905 is resting in the Space Center Houston. The mockup space shuttle Independence, a full-scale replica mated atop the SCA N905 and kept at the Independence Plaza opened to the public. 

Will There be any Future Need? 

The space shuttle program is discontinued and it is unlikely to think that there will be any requirements in the future. The development of fully reusable space vehicles from companies like SpaceX has eliminated the use of space shuttle-like vehicles to transport crew to and from the International Space Station (ISS). Therefore, shuttle carrier aircraft will be history and remembered for the unmatched contribution they made to the technological advancements. 

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