An illustration of the "family" of launch vehicles Stratolaunch plans to offer, from the existing Pegasus XL (left) to a potential reusable spaceplane (right.) Credit: Stratolaunch

WASHINGTON — Stratolaunch announced Aug. 20 that it is developing a family of vehicles, including a reusable spaceplane, that could launch from the giant aircraft it is developing.

In a statement, Stratolaunch said it will offer customers a range of launch vehicle options for missions starting in 2020 to place small and medium-sized payloads into low Earth orbit, confirming long-running speculation in the industry about the company’s plans.

Those vehicles, to be launched from the company’s giant aircraft, “will offer a flexible launch capability unlike any other,” said Jean Floyd, chief executive of Stratolaunch, in a statement. “Whatever the payload, whatever the orbit, getting your satellite into space will soon be as easy as booking an airline flight.”

That family of vehicles will start, at the small end, with the Pegasus XL rocket provided by Northrop Grumman Innovation Systems (formerly Orbital ATK), with launches beginning in 2020. Stratolaunch had announced an agreement with Orbital ATK in 2016 to use the Pegasus on its aircraft, with the ability to launch as many as three of the rockets on a single flight.

For many industry observers, though, the Pegasus XL appeared to be an odd choice, given that Orbital ATK already had its own aircraft for launching that rocket. Moreover, Pegasus has been restricted primarily to NASA missions in recent years, despite the booming interest in small satellites, because of the vehicle’s high price. Stratolaunch executives argued that there were potential national security applications of that system, such as for responsive launch of an entire constellation of smallsats to different orbits on a single flight.

Stratolaunch, though, had been working on its own launch vehicle systems. The company hired a former SpaceX executive, Jeff Thornburg, as its vice president of propulsion in 2017. The company also signed a Space Act Agreement last September to conduct engine tests at NASA’s Stennis Space Center.

At the time, the company said little publicly about that agreement or any engine development work. “As we’ve said in the past, we’re exploring a number of launch system possibilities to provide reliable access to space,” a company spokesman told SpaceNews last November.

In its new announcement, Stratolaunch said it is developing what it calls a Medium Launch Vehicle, which it describes as a “medium-class air-launch vehicle optimized for short satellite integration timelines, affordable launch and flexible launch profiles.” The first flight of that vehicle, capable of placing up to 3,400 kilograms into LEO, is scheduled for 2022.

Stratolaunch will also offer a variant of that vehicle, called Medium Launch Vehicle – Heavy, that uses three cores in its first stage, similar to the Delta 4 Heavy or Falcon Heavy. That vehicle would be able to place 6,000 kilograms into LEO. The company didn’t give a timeline for that vehicle, which it described as being in “early development.”

The company offered few other technical details about the vehicle, such as its propulsion system, payload performance to other orbits or volume within the rocket’s payload fairing. The company said it will offer more details about its launch vehicles “and on our vision for improved access” to space by the end of this year.

Stratolaunch confirmed that, in addition to those launch vehicles, it is in the design study phase for a reusable spaceplane that would be launched from the aircraft. That vehicle would initially be used for cargo, but a “follow-on variant” would be able to carry astronauts.

The idea of using the Stratolaunch airplane is not new. In 2014, the company said it was working with Sierra Nevada Corporation to study launching a scaled-down version of Sierra Nevada’s Dream Chaser on Stratolaunch’s aircraft, propelled by an Orbital-developed launch vehicle that Stratolaunch was then considering.

The companies elected not to proceed with that concept, but Paul Allen, the Microsoft co-founder who established Stratolaunch and is funding the venture, said in an interview in the recent book The Space Barons that the company was studying a spaceplane concept called Black Ice. Company officials, speaking on background at the 34th Space Symposium in April, confirmed then that the Black Ice concept is still under study but offered few other details about it.

All of those vehicle concepts, though, require the use of Stratolaunch’s giant aircraft that is still in development. The aircraft is still going through a series of taxi tests leading up to a first flight, and was last seen outside its hangar at the Mojave Air and Space Port in California the weekend of Aug. 11.

“We didn’t make it to the main runway for taxi testing this weekend,” Floyd tweeted Aug. 12. “Successfully completed fueling ops, engine runs, and communications testing. We’ll be outside again very soon.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...