Unity was described in a statement appearing on Virgin Galactic's website as being, "built from scratch for Virgin Galactic by The Spaceship Company's talented team of aerospace engineers and technicians".
The spacecraft, VSS Unity, launched from Mojave, California and successfully reached speeds of up to mach 1.6 for the first time under rocket power.
It was the first rocket-powered flight for VSS Unity, Virgin Galactic's second SpaceShipTwo vehicle, after seven previous glide test flights.
Virgin Galactic CEO George Whitesides said: "On rocket shutdown, Unity continued an upwards coast to an apogee of 84,271 feet before readying for the downhill return".
VSS Unity replaces VSS Enterprise, a rocket plane destroyed in an October 2014 crash that killed one pilot and injured another.
Virgin Galactic engineers are now reviewing the data on flight, motor and vehicle performance after this week's successful flight.
"#WhiteKnightTwo pilots, Mike "Sooch" Masucci and Nicola Pecile have landed VMS Eve safely, completely today's important test flight @MojaveAirport", the tweet said. Images are courtesy of Virgin Galactic.
SpaceShipTwo VSS Unity had undergone two years of ground and atmospheric tests ahead of its first powered flight.
On commercial flights, pair will travel up to 80 km above the earth's surface, an altitude defined as the edge of outer space by NASA. About 700 customers have already put down deposits for space tourism packages costing as much as $250,000.
WhiteKnightTwo launched from Mojave in the morning and carried Unity up to an altitude of 6,500 feet over the Sierra Nevada Mountains. The test brings the firm a big step closer to its ultimate goal of taking tourists to space.
It is expected that VSS Unity in the near future will make several flights with the engine and will first be released into space. The successful test comes nearly four years after a fatal accident on an earlier version of the spaceship (See: Virgin Galactic space craft crashes in California, killing pilot during test flight).