What to do when your 747s are beginning to age and you need to get the last bit of use out of them? Simple: turn them into satellite launchers. Virgin Galactic says that it has repurposed an 2001 747-400 named “Cosmic Girl” to serve as a dedicated launch platform for its LauncherOne small satellite launch service.

Cosmic Girl will be retrofitted with an attachment on its left wing, close to where the fifth engine is found on some other 747-400s. The LauncherOne rocket would mount to the attachment, and be launched mid-flight at around 35,000 feet. The process stands to save Virgin Galactic a good deal in launch costs given the rocket has less air resistance to get into orbit, which means far lower gas costs.

“Air launch enables us to provide rapid, responsive service to our satellite customers on a schedule set by their business and operational needs, rather than the constraints of national launch ranges,” Virgin Galactic CEO George Whitesides said in a statement.

Virgin already has a use for its new mid-air rocket launcher: the LauncherOne service will be used to launch nearly 2,400 satellites as part of a partnership with Qualcomm. A company called OneWeb will maintain these satellites when they launch in 2018, aimed at providing Internet access to underserved areas. Another multi-million dollar contract was signed with NASA to launch about a dozen experimental satellites during test flights for LauncherOne.

Virgin says that the service could allow it to launch satellites for customers in as little as 24 hours notice, versus the current six month plus waiting period companies need to plan for with standard rocket launches. LauncherOne can also handle more heavier payloads thanks to recent upgrades: the rockets now have a maximum payload of up to 400 kilograms, aimed at making the service feasible for a wider array of clients, especially lucrative government contracts.

Test flights for the rocket launcher-equipped 747 are expected to start in 2017.