Almost two years after the loss of Virgin Spaceship Enterprise (VSS Enterprise), a second Virgin Galactic SpaceShipTwo vehicle — dubbed VSS Unity — took to the air for the first time on 9th September above the Mojave desert in California.

The vehicle, which was built by Virgin Galactic subsidiary The Spaceship Company and formally unveiled in February, remained mated to the WhiteKnightTwo mothership, VMS Eve, for the duration of the flight.

The captive flight, which the company compared to a flying wind tunnel test, lasted 3 hours 43 minutes. The next flight will take place once the data gathered during the flight have been fully analysed.

The next phase of testing, according to Virgin Galactic, will involve “a series of glide flight tests, during which Unity is released to fly home on her own, followed by rocket-powered flight tests of increasingly ambitious scope.“

VSS Enterprise was lost following premature deployment of the vehicle’s innovative feather mechanism, designed to increase stability and drag during re-entry by moving the tail stabilizers from horizontal to vertical position.

During three rocket-powered test flights completed prior to the accident, VSS Enterprise had peaked at 71,000ft and Mach 1.4 — not enough to carry six passengers into space.

The company had switched to a new plastic-based fuel that was being tested for the first time when VSS Enterprise was lost. Though the engine was not deemed to have been a factor in the accident, subsequent reports indicated that the company was planning to revert to the original rubber-based fuel.

There is no current target date for the first flight with fare-paying passengers.