Virgin Galactic and its Long Beach-based spinoff Virgin Orbit is moving closer to launching satellites.

On Monday, July 31, Cosmic Girl touched down at Long Beach airport, where Virgin Orbit employees were eagerly waiting, along with Long Beach mayor, city dignitaries and media. Cosmic Girl is a 747-400 jumbo jet that had been a commercial carrier for Virgin Atlantic. However, for the past 16 months, it’s undergone modifications and extensive testing in Texas that transformed it from commercial jet to an air-launch platform, according to GeekWire, Space News and the Long Beach Post.

The plan is to use Cosmic Girl to bring Virgin Orbit’s LauncherOne rockets to an altitude of 35,000 feet before the rockets are released. By using a plane instead of a ground-based launch platform, Virgin Orbit will have more flexibility to use several airports for launches and operate in spite of inclement weather that would delay ground-based launches.

Following the modifications, the FAA awarded Cosmic Girl an experimental airworthiness certificate, clearing the way for test flights and launches. Virgin Orbit that it’s planning Cosmic Girl’s first flight for the first half of 2018, which will occur at the Mojave Air and Space Port.

Virgin Orbit’s LauncherOne rockets are two-stage, expendable, LOX/RP-1 rockets. Two-stage means it uses two individual engines and propellant. According to the Virgin Orbit site, once released from Cosmic Girl, the main stage engine (“NewtonThree”) will fire first for about three minutes. Then, that section, or stage, of the rocket will separate and another engine (“NewtonFour”) will fire and carry the satellite into orbit. Expendable means that each LauncherOne rocket is designed to be used only once. LOX/RP-1 refers to the type of fuel used (liquid oxygen and a highly refined form of kerosene).

Virgin Orbit will offer low-cost launch services for small satellites, serving both commercial and government customers. It already has a deal with OneWeb to launch 39 satellites and create a satellite constellation for a global broadband internet.