Paul Allen’s Stratolaunch puts world’s biggest airplane into the sky for first time

Stratolaunch, the aerospace venture founded by the late Microsoft co-founder Paul Allen, sent the world’s biggest airplane into the air today for its first flight test.

The twin-fuselage plane, which incorporates parts from two Boeing 747 jumbo jets and has a world-record wingspan of 385 feet, took off from Mojave Air and Space Port in California for what’s expected to be a flight lasting a couple of hours.

Stratolaunch didn’t immediately issue any statements about the flight, which had been anticipated for months — but Thomas Zurbuchen, NASA’s associate administrator for the science mission directorate, invoked Allen’s memory in his tweeted congratulations.

“This is about going to the edge of space and beyond!” Zurbuchen wrote. “I only wish the late @PaulGAllen could see this — his memory and impact lives on.”

Allen founded Stratolaunch in 2011 to develop the large carrier airplane as a flying launch pad for orbital-class rockets. A year ago, Stratolaunch executives said they planned to fly the plane this past summer, but on-the-ground runway tests took longer than expected.

After Allen’s death in October at the age of 65, the venture went through a round of restructuring. In January, Stratolaunch drastically reduced its staff, put its plans to develop its own rocket engine and lineup of launch vehicles on hold, and said it would focus on flight-testing its monster airplane.

The plan ahead calls for further tests over the next 12 to 18 months, with the aim of getting the plane fully certified by the Federal Aviation Administration. Stratolaunch has already struck a deal to use Northrop Grumman’s Pegasus XL rocket to send payloads weighing as much as 816 pounds (370 kilograms) to low Earth orbit. Launches would begin once the plane, nicknamed Roc, wins operational certification.

Stratolaunch’s air-launch system is designed to carry multiple rockets up to an altitude of about 40,000 feet, and then drop them into the air to fire up their rocket engines. The advantage of such a system is that it can take off from any runway that’s long enough to accommodate the plane, fly around bad weather if need be, and launch a satellite into any orbital inclination.

Potential customers range from commercial satellite operators to the U.S. military. It’s not clear, however, just how big of a market niche Stratolaunch will occupy. Because satellites are getting smaller and smaller, with more and more capabilities, some say the world’s biggest plane may be too big to make business sense.

Stratolaunch was a spinoff from Allen’s backing for the SpaceShipOne private space effort that won a $10 million prize in 2004. Other air-launch spinoffs include Virgin Galactic and Virgin Orbit, two ventures that are under the wing of British billionaire Richard Branson’s Virgin Group. This week, Virgin Orbit announced a deal to use Guam as a base of operations for sending small satellites into space with its LauncherOne air-launch system