Stratolaunch, the aerospace company founded by the late Seattle billionaire Paul Allen, put the world’s biggest airplane through its second flight test today, two years after the first flight.
“We are airborne!” Stratolaunch reported in a tweet.
Today’s takeoff from California’s Mojave Air and Space Port at 7:28 a.m. PT marked the first time the plane, nicknamed Roc after the giant bird of Arabian and Persian mythology, got off the ground since Stratolaunch’s acquisition by Cerberus Capital Management in October 2019.
Roc rose as high as 14,000 feet and traveled at a top speed of 199 mph during a flight that lasted three hours and 14 minutes — which is close to an hour longer than the first flight on April 13, 2019. During that earlier flight, the airplane reached a maximum speed of 189 mph and maximum altitude of 17,000 feet.
Zachary Krevor, Stratolaunch’s chief operating officer, said today’s flight accomplished all of its test objectives by checking the performance of improved instrumentation, a more robust flight control system and an environmental control system that allowed the pilots to work in a pressurized cockpit. Krevor said the crew included chief pilot Evan Thomas, pilot Mark Giddings and flight engineer Jake Riley.
The flight’s spiciest moment came at touchdown, when one of the mammoth plane’s landing gears settled the runway while the other was still in the air. “We did touch down initially on one gear, but that’s exactly the technique we prefer to use during a crosswind landing,” Krevor told GeekWire during a post-landing teleconference. “Though we stayed within our crosswind limits, we did have a little bit of a crosswind, and the aircrew did an excellent job of bringing the aircraft down.”
Since Roc’s first flight in 2019, the business model for the 10-year-old venture has shifted: In its early years, Stratolaunch focused on using Roc as a flying launch pad for sending rockets and their payloads to orbit. The concept capitalizes on the air launch system pioneered by SpaceShipOne, which won financial backing from Allen and won the $10 million Ansari X Prize in 2004,
The new owners still expect to use Roc for air launch, but the current focus is on using the plane as a testbed for Stratolaunch’s hypersonic flight vehicles, Once the plane is cleared for regular operations, perhaps next year, Stratolaunch could begin launching its Talon-A prototype hypersonic plane.
David Millman, Stratolaunch’s chief technology officer, said the company plans to build three hypersonic vehicles. He said that should open the way for conducting hypersonic tests at least once every 17 days, matching the tempo of flights for the X-15 rocket plane in the 1960s,
Hypersonic flight at five times the speed of sound is a big deal for military applications. Russia and China are said to be working on hypersonic weapons systems, and the U.S. military is keen to keep up. Stratolaunch expects its technology to figure in the Pentagon’s plans.
“That’s exactly one of the areas that we’re looking at: how can we help the Department of Defense in mitigating risks for all their extensive flight testing,” Millman told GeekWire.
Millman said Stratolaunch’s Talon testbed will be able to carry payloads, test materials and fly a variety of profiles that can help the Pentagon determine characteristics of hypersonic flight before it conducts costly full-blown flights of its own hypersonic vehicles.
“What we’re doing is providing a path or them to test a lot of their technologies in a simpler way, in a repeatable way, in a useful way so that they can get to their all-up rounds much quicker,” Millman said.
Stratolaunch hasn’t ruled out eventually pursuing other applications for its launch system, including sending satellite payloads and crewed space planes into orbit.
Other companies, principally including Virgin Orbit, are also working on next-generation air launch technology. Such systems hold the promise of greater versatility and quicker response time for launching payloads, due to the fact that the carrier planes can take off from a wide variety of runways, fly around inclement weather and theoretically launch their payloads in any desired orbital inclination.
Stratolaunch’s twin-fuselage, six-engine Roc airplane is in a class by itself, thanks to its world-record wingspan of 385 feet. In comparison, the wingspan of the modified Boeing 747 that Virgin Orbit is using comes to 211 feet. The previous record-holder was the Spruce Goose, a prototype seaplane that made its debut in 1947 and had a 320-foot wingspan. Built by Mojave-based Scaled Composites, Roc has the capacity to carry more than 500,000 pounds of payload.
This is an updated version of a report first published at 10:31 a.m. PT April 29.