Instead, Orbital Sciences Corp. is doing design studies for such a space vehicle. The parting of ways is amicable, and opens up a significant new project for Orbital. Stratolaunch CEO Gary Wentz announced the change in a Nov. 27 email.
The Stratolaunch project was announced in December 2011, and is funded by Paul Allen, cofounder of Microsoft. It envisions an enormous air-launch system that, in its original configuration with a SpaceX rocket, was to be capable of lofting 6,100 kilograms to low Earth orbit or 2,300 kilograms to geosynchronous orbit.
Scaled Composites of Mojave, Calif., is designing and building the system’s twin-boom mother ship: a massive, 222,000-kilogram airplane with a 117-meter wingspan capable of flying 2,400 kilometers from a launch site before deploying a rocket. It will be the largest aircraft ever built.
Dynetics Corp. of Huntsville, Ala., is building the mating and integration system that will secure the rocket to its carrier aircraft.
“We agreed with SpaceX that to meet our design requirements, the existing Falcon 9 architecture would require significant structural modifications to incorporate a fin/chine and to be carried horizontally,” Wentz said. “As we studied the design, it became apparent that SpaceX would have to make significant modifications to their manufacturing process to accommodate our configuration, which would have a pronounced effect on their business model.”
The Stratolaunch craft would include four or five engines, and will be launched horizontally in contrast to the Falconís vertical takeoff. SpaceX has not publicly commented on the break with Stratolaunch.
Orbitalís Pegasus is air launched from a reinforced L-1011 aircraft. There have been 41 Pegasus launches. They launch satellite payloads of about 450 kilograms. But only one, for April 2013, is now on the flight manifest. Orbital is hard at work on the Antares rocket and Cygnus cargo carrier for NASAís Commercial Crew Resupply program.
Allen also funded SpaceShipOne, designed and built by Bert Rutanís Scaled Composites, it won the $10 million X Prize in 2004, by flying above 100 kilometers twice within two weeks.
Developing SpaceShipOne cost about $28 million. Allen said he expected to spend “at least an order of magnitude more” on Stratolaunch than he spent on SpaceShipOne.