To be launched on a Lockheed Martin Titan III rocket, Dyna-Soar was for hypersonic flight research but the programme was cancelled before the first vehicle was completed. Some of its subsystems were used in later X-15 flight research and Dyna-Soar became a testbed for advanced technologies that contributed to projects, including the Space Shuttle.
Above: SpaceShipTwo is carried between the two fuselages of White Knight II
Virgin Galactic's commercial operations will now start from New Mexico's Spaceport America in 2010 and not from Mojave air and space port in California, as originally planned, but the WK2, SS2 launch system will be test flown by Scaled at the Californian port.
At its 23 January press conference at the American Museum of Natural History in New York city Virgin Galactic described SS2 as using the same basic technology, construction and design as its predecessor SpaceShipOne (SS1), as 100% composite and twice as large as the $10 million X-Prize winning vehicle, SS1.
Above: SpaceShipTwo transitions into feathering mode for its reentry
The SS2 is 18.3m (60ft) long, has a wingspan of 12.8m, a tail height of 4.5m with a passenger cabin that is 3.66m long and 2.28m in diameter. Despite being so much larger than SS1, SS2 will still use a front nose skid, and not nose gear. Released at 50,000ft (15,200m) by WK2, the rocket glider's apogee is expected to be up to 110km (68 miles).
Above: SpaceShipTwo is under construction at Scaled Composites
The carrier aircraft, WK2, is now 23.7m-long, it still has a wingspan of 42.7m, with a tail height of 7.62m and its integration is now 80% complete - with the assembly of the wing underway in preparation for its mating with the twin fuselages.
The WK2 will have four Pratt and Whitney PW308 engines, as revealed by Flight in September last year. And as Flight has also reported WK2's crew and passenger cabin will be the same; for training purposes.
Above: White Knight II under construction with its twin fuselages being fitted with their tail fins at Scaled Composites
Virgin Galactic also announced that the SS2 simulator is now operational, ahead of the previous March 2008 date that had been given. It is already being used for pilot training.
Above: Brian Binnie, Scaled Composites pilot, sits in the SpaceShipTwo simulator