Space Technology ~ Virgin Galactic Reveals Boeing 747 For LauncherOne

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Looking for a large carrier aircraft to meet increased payload requirements of potential customers for its LauncherOne satellite lifter, Virgin Galacticdecided on a Boeing 747 and knew just where to find one. The space start-up says it will use a 747-400 formerly operated by its sister company Virgin Atlantic Airways and modify it to carry the space launcher to an altitude of 35,000-40,000 ft., where it will be air-dropped and launched into orbit. 

The 747 joins Virgin Galactic’s existing launch platform, the WhiteKnightTwo carrier aircraft, which will now be dedicated to launching the SpaceShipTwo suborbital vehicle.

Virgin opted to acquire and develop the higher payload launch capability using the 747-400 after earlier deciding to increase the capacity of Launcher-One to loft 200-kg satellites into high-altitude, sun-synchronous orbits. As a result both first- and second-stage engines are now targeted at considerably higher thrust than the initial design of LauncherOne. First- and second-stage engines are scaled-up versions of the same baseline liquid oxygen/RP-1 (kerosene)-fueled, turbopump-fed rocket engine design.

The decision to scale up both the launcher and its carrier aircraft resulted when “we heard loud and clear that our customers wanted increased payload capability,” says Virgin CEO George Whitesides. “We did a worldwide search, and after looking around, the best model turned out to be Virgin’s 747-400.” As the aircraft formerly operated for Virgin with the name “Cosmic Girl,” Whitesides says the selection of this particular aircraft was “just meant to be.”

The aircraft was retired from Virgin Atlantic’s fleet in late October and flown to San Antonio for baseline aerodynamic and structural testing to prepare for full-scale modification in 2016. The initial assessment, conducted at Texas-based MRO provider VT San Antonio Aerospace, will be followed by a full D check maintenance inspection. “The D check will be complete around late January 2016. Then we will work with our modification contractor to reposition the aircraft and strengthen the structure of the inboard left wing to hold a 55,000-lb. rocket as well as [provide] significant margin for future work,” says John Couluris, head of launch systems at Virgin Galactic.

Modifications will include installation of a removable payload adapter which will interface between the wing and the launch vehicle. The adapter will connect to the inboard lower wing surface at a specially strengthened section originally designed into the 747 for the carriage of spare engines. The aft “canoe” flap fairing on the inboard trailing edge flap will also be reduced in size to ensure adequate clearance between the aft end of the launcher and the flap.

The adapter, which will include redundant actuation and fail-safe separation connections, will be attached to the 55,000-lb. launcher with three hooks. Attachment points will be located on the casing close to the forward end of the liquid oxygen tank on the first stage and between the aft end of the same tank and the front end of the first-stage RP-1 fuel tank, says LauncherOne chief engineer Kevin Sagis. 

“When it releases from those points, we expect the loads will be reduced,” he says. “The plan is to do wind tunnel tests of the rocket by itself and perform separation analysis using computational fluid dynamics.” Captive-carry, separation and initial launch tests will take place from the company’s Mojave facilities in 2017.

Progress also continues with testing of the LauncherOne satellite launch vehicle’s NewtonThree main-stage engine and full-duration gas generator tests of the NewtonFour upper-stage engine. The latest hot-fire runs conducted at the company’s Mojave facilities include a test of the more powerful NewtonThree engine that exceeded 90 sec. “That means the rocket was thermally stable, and so that retires a lot of risk in the engine,” says Sagis. “It gives us confidence in the turbopump and the thrust chamber.”

Multiple full-duration tests of the gas generator for the second-stage NewtonFour have also been completed with tests exceeding 6 min. “We fired a pressure-fed version about 18 months ago, and we are now completing fabrication of turbopumps for that. We will also have a thrust chamber on the stand for testing in the first part of 2016,” Sagis adds.

Fabrication work is also advancing on scaled versions of the composite tanks, with tests planned on a 36-in., or roughly half-scale, tank due to take place in coming weeks. The work is being conducted at Virgin Galactic’s newly opened 150,000-sq.-ft. site in Long Beach, California. Virgin Galactic President Steve Isakowitz says staff at the site has grown to more than 150. “We have also completed multiple long-duration hot fires of our liquid rocket engines, doubled the [LauncherOne] payload capacity, and welcomed two game-changing customers from both new space and government, OneWeb and NASA," he says.