Virgin Galactic shares jump after announcing it will test the SpaceShipTwo Unity on Saturday

Unlike other commercial spaceflight companies, such as Blue Origin, Virgin Galactic initiates its flights without using a traditional rocket launch.

Instead, the firm launches its passenger-laden SpaceShipTwo and other craft from a carrier plane, dubbed WhiteKnightTwo.

WhiteKnightTwo is a custom-built, four-engine, dual-fuselage jet aircraft, designed to carry SpaceShipTwo up to an altitude of around 50,000 feet (15,240 metres).

The first WhiteKnightTwo, VMS Eve – which Virgin Galactic has used on all of its test flights – was rolled-out in 2008 and has a high-altitude, heavy payload capacity.

Unlike other commercial spaceflight companies, such as Blue Origin, Virgin Galactic initiates its flights without using a traditional rocket launch. Instead, the firm launches its passenger-laden SpaceShipTwo and other craft from a carrier plane, dubbed WhiteKnightTwo. Once SpaceShipTwo has propelled itself into space its engines shut off for a period of weightlessness before returning home

Once it reaches 50,000 feet (15,240 metres) the carrier plane releases SpaceShipTwo, a reusable, winged spacecraft designed to carry six passengers and two pilots into space.

Virgin Galactic has named its first SpaceShipTwo VSS Unity – the craft that the company has used in all of its test flights – though the firm is expected to build more in future.

Once released from WhiteKnightTwo, SpaceShipTwo’s rocket motor engages ‘within seconds’, according to Virgin Galactic.

The craft will then fly approximately three and a half times the speed of sound (2,600mph/4,300kph) into suborbital space, reaching up to 360,890ft (110,000 metres) above the Earth’s surface.

WhiteKnightTwo (artist's impression) is a custom-built, four-engine, dual-fuselage jet aircraft, designed to carry SpaceShipTwo up to an altitude of around 50,000 feet (15,240 metres)

WhiteKnightTwo (artist’s impression) is a custom-built, four-engine, dual-fuselage jet aircraft, designed to carry SpaceShipTwo up to an altitude of around 50,000 feet (15,240 metres)

This altitude is defined as beyond the edge of outer space by Nasa.

After the rocket motor has fired for around a minute, the pilots will shut it down, and passengers can then take off their seatbelts to experience weightlessness for several minutes.

The pilots will manoeuvre the spaceship to give the best possible views of Earth and space while raising the vehicle’s wings to its ‘feathered’ re-entry configuration, which decelerates the craft and stabilises its descent.

As gravity pulls the spaceship back towards the Earth’s upper atmosphere, astronauts will return to their seats ready to return to our planet.

At around 50,000 feet (15,240 metres), after re-entry, the pilot will return the spaceship’s wings to their normal configuration, ready to glide back to Earth for a smooth runway landing. 

Once it reaches 50,000 feet (15,240 metres) the carrier plane releases SpaceShipTwo, a reusable, winged spacecraft designed to carry six passengers and two pilots into space. Virgin Galactic has named its first SpaceShipTwo VSS Unity (pictured) - the craft that the company has used in all of its test flights - though the firm is expected to produce more in future

Once it reaches 50,000 feet (15,240 metres) the carrier plane releases SpaceShipTwo, a reusable, winged spacecraft designed to carry six passengers and two pilots into space. Virgin Galactic has named its first SpaceShipTwo VSS Unity (pictured) – the craft that the company has used in all of its test flights – though the firm is expected to produce more in future