Stratolaunch Systems will use rockets made by Orbital ATK to launch satellites from the huge aircraft it is developing in Mojave, the companies announced Thursday.
Under a multiyear "production-based partnership," the companies said, Orbital ATK will provide "multiple" Pegasus XL air-launch rockets to be used with the Stratolaunch aircraft, which, when completed, will have the largest wingspan of any plane ever built.
With the Pegasus XL rockets, the Stratolaunch aircraft will be able to launch small satellites weighing up to 1,000 pounds, according to the firms' joint statement released Thursday.
Pegasus rockets already have done this kind of work: Orbital ATK has used them to launch satellites from the belly of its Stargazer aircraft.
The Stratolaunch craft is intended to blast satellites into orbit from midair, and is a project of Microsoft cofounder Paul Allen's Vulcan Aerospace. The craft will be fully operational by the end of the decade, Vulcan Aerospace said in an email.
This is the second time Stratolaunch Systems has said it will work with Orbital ATK on its air-launch rockets.
Stratolaunch Systems initially said SpaceX would build the rocket booster, but the partnership with Elon Musk's Hawthorne space company ended after SpaceX said it wanted to focus on its standard Falcon 9 rocket rather than making a variant for Stratolaunch, according to Space News.
Stratolaunch then turned to Orbital ATK, but that plan was shelved. The partnership ended that time, Vulcan Aerospace said Thursday, because the satellite market "evolved" and the two companies came to a mutual agreement that the "initial project was no longer able to meet our customers' needs."
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1:45 p.m.: This article was updated with details about when the Stratolaunch craft would be fully operational and Stratolaunch's previous partnership with Orbital ATK.