Space.com – After the exit of launch services provider SpaceX as its rocket subcontractor, Stratolaunch Systems has turned to Orbital Sciences of Dulles, Va., to keep the world’s largest air-launch-to-orbit system on track for a 2017 test flight.
What those configurations were, neither Stratolaunch nor Orbital would say. Huntsville, Ala.-based Stratolaunch had been banking on using a liquid-fueled booster from SpaceX. Orbital specializes in solid-fueled rockets. The first stage of the liquid-fueled Taurus 2 rocket Orbital expects to debut in 2013 relies on a Ukranian-supplied first stage powered by a rebadged Russian engine. While the company has extensive experience with air-launched systems, it has not built one with the payload-carrying capacity that Stratolaunch seeks.
Orbital’s solid-fueled Pegasus rocket, which can loft 450 kilograms to low Earth orbit, has logged 41 launches since 1990. Only three of these were failures, according to an online mission history maintained by Orbital. However, Pegasus-class business has all but dried up. The single Pegasus XL launch of 2012 was the rocket’s first flight in four years, and there is only one Pegasus XL mission on Orbital’s manifest today: the April 2013 launch of NASA’s Interface Region Imaging Spectrograph space telescope.
Stratolaunch plans to build 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, Mojave, Calif., was tapped to build the system’s twin-boom mothership: 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. Dynetics Corp. of Huntsville, Ala., is building the mating and integration system that will secure the rocket to its carrier aircraft.
As first reported by Flightglobal.com Nov. 27, the main reason Stratolaunch and SpaceX parted ways was because SpaceX, decided it did not want to disrupt its Hawthorne, Calif., assembly line to accommodate the design changes required to turn its nine-engine, liquid-fueled Falcon 9 into a four- or five-engine air-launched booster.