Paul Allen’s Stratolaunch: The engineering behind the world’s largest airplane

Picture a football field, goalposts on each end with 100 yards of finely manicured turf stretching between them. Fans in one end zone have to squint to make out what’s happening at the opposite end. A long kick return leaves even world-class athletes winded.

Now imagine an airplane with a wingspan 25 feet longer than that. What you’re picturing is the Stratolaunch, Paul Allen’s satellite-launching airplane that’s unlike any aircraft you’ve seen before.

Why so big?

Peeking out of an extra-large, custom airplane hangar earlier this month, Stratolaunch made its first public appearance and secured its place as the world’s largest ever airplane (by wingspan). The gargantuan aircraft is essentially a rocket launcher, designed to hurl satellites into space for the purposes of communications and scientific research. Unlike traditional rocket launchers, however, Stratolaunch will release rockets from the air, not from the ground.

In order to carry a rocket up to the Stratosphere—around 35,000 feet—Stratolaunch needed to be big. Very big. It has to be robust enough to hold 250,000 pounds of fuel and a rocket payload (satellites, space probes, etc.) of up to 550,000 pounds. Any aircraft tasked with carrying a load that large will end up being very large itself.

A feat of engineering

Built by Scaled Composites, an aircraft design and manufacturing company based in Mojave, California, Stratolaunch is the impressive effort of more than 300 engineers and fabricators. In addition to being the world’s largest airplane by wingspan, it’s also the largest aircraft to be made entirely of composites. There isn’t another aircraft comparable in size or design. It’s truly one of a kind.


Stratolaunch in numbers

•  2 FUSELAGES connect by a “center wing,” making the Stratolaunch look more like a flying catamaran than a rocket launcher.

•  3 CREW MEMBERS needed to operate the aircraft—a pilot, co-pilot and flight engineer.

•  6 BOEING 747 ENGINES required to power the massive airplane.

•  28 WHEELS used for taxiing and landing.

•  2,000 NAUTICAL MILES of approximate operational range.

•  1.3 MILLION LBs of maximum takeoff weight.


Space race 2.0

Whether Paul Allen’s air-launch-to-orbit technology truly takes off remains to be seen. Stratolaunch Systems faces stiff competition from SpaceX, which is revolutionizing ground launches with its large, reusable Falcon 9 rocket.

SpaceX CEO Elon Musk expressed his doubts about horizontal air launches in a Q&A at the Royal Aeronautical Society, saying:


“I think it's important to keep in mind that the payload to orbit advantage from an air launch is're high up there and so surely that's've got some speed and altitude, you can use a higher expansion ratio on the nozzle, doesn't all that add up to a meaningful improvement in payload to orbit? The answer is no, it does not, unfortunately. It's quite a small improvement. It's maybe a 5% improvement in payload to orbit, something like that, and then you've got this humungous plane to deal with.

And then, once you get beyond a certain scale, you just can't make the plane big enough.”


However, Allen is confident that Stratolaunch’s “airport-style approach to operations” and ability to avoid hazards like “inclement weather, airborne traffic and heavy marine activity” give it a key advantage over ground-launch technology.

The Stratolaunch team plans to perform ground and in-flight testing over the next several months. If everything goes according to plan, it will host a launch demonstration as early as 2019.

As a custom fabricator of technology used in the next frontier of space exploration, we’re excited to continue our custom projects for the aerospace and space industries.

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