Scaled Composites aims to open up more of Virgin Galactic's SpaceShipTwo (SS2) supersonic flight envelope in the coming weeks, following the second successful rocket-powered test over Mojave, Calif., on Sept. 5.

The test, which reached Mach 1.43 and an apogee of 69,000 ft., included the first use of the tail-plane feathering reentry system on a powered flight, and at higher speed and altitude. The vehicle's Sierra Nevada RM2 solid rocket motor was also tested for a longer duration—firing for 20 sec., 4 sec. more than the first powered flight on April 29. Scaled says in addition to supersonic, aerodynamic flight-envelope expansion and evaluation of the feather, the flight also provided data on wing-lift structural performance during acceleration and the highly loaded vertical pull-up maneuver.

The flight, conducted by test pilots Mark Stucky and Clint Nichols, was the 29th free flight of the SS2, which was carried aloft to release altitude by the WhiteKnightTwo (WK2) carrier aircraft shortly after 8 a.m. PST. The crew lit the rocket 4 sec. after release, pulling up into a vertical climb overhead of the former Honda Proving Center test track in an area north of California City. The rocket was shut down 20 sec. later and, as the now unpowered SS2 continued supersonically toward its apogee of 69,000 ft., the crew noted some mild roll oscillation, which Virgin says was “as predicted.” Eight seconds after passing 66,000 ft., and slowing down, the SS2 feather mechanism was actuated. Having verified its operation for nearly 30 sec., the crew retracted the device, which was fully stowed after another 30 sec. The vehicle continued its descent and was landed safely by Nichols at 9:25 a.m. PST after a free-flight lasting 14 min.

Despite the longer-than-expected interval between the first and second rocket-powered tests, Virgin Galactic Special Projects Vice President Will Pomerantz says the first flight to sub-orbital flight is still on track to take place by year-end.

Further flights will continue to expand the supersonic aerodynamic flight envelope, launch weight and structural loads. Testing is expected to end with a maximum apogee demonstration flight to 361,000 ft. (110 km), after which SS2 developer Scaled Composites will turn the vehicle over to Virgin Galactic. The latter plans to begin commercial suborbital services from Spaceport America, N.M., in 2014.