(Bloomberg) -- Virgin Galactic Holdings Inc. is contracting with Boeing Co.’s Aurora Flight Sciences to design and build two motherships, twin-hulled flying machines that carry its passenger spaceships to about 50,000 feet and release them to travel into space.

Aurora will immediately begin development of the next generation of air-launch carriers for Virgin Galactic, according to a statement late Wednesday. The first of the vehicles is expected to enter service in 2025, the same year Virgin Galactic plans to begin revenue flights of its new, more durable Delta-class spaceship.

The space tourism company, founded by entrepreneur Richard Branson, still sees its next commercial flight coming in the first quarter of 2023, after it completes a structural overhaul of its existing carrier plane, VMS Eve. The vehicle requires new horizontal stabilizers and a redesigned pylon to carry the spaceships to their drop altitude.

See also: Virgin Galactic Drops to Record Low After Launch Delay

Virgin Galactic targets flying up to 200 launches a year with the new motherships. Aurora plans to manufacture the aircraft at its plants in Mississippi and West Virginia before shipping them to a Virgin Galactic facility in California for final assembly. Boeing acquired Aurora, a leading designer of high-altitude and autonomous vehicles, in 2017.

Virgin Galactic shares climbed 4.7% at 5:13 p.m. after regular trading in New York. The stock has fallen 52% this year through Wednesday’s close.

(Corrects spelling of company name in headline)

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