LOS ANGELES —Bolstered by its recent second-round NASA Commercial Crew Development Program (CCDev2) win to continue development of the Dream Chaser spaceship, Sierra Nevada Corp. is revealing new details of its plan to conduct full-scale drop tests in 2012 using the Scaled Composites-developed WhiteKnightTwo mothership.

Sierra Nevada is one of the big winners in the second round of NASA’s CCDev program, netting $80 million of the total $269.3 million payout aimed at maturing concepts for private spacecraft to carry astronauts to the International Space Station and other low Earth orbit destinations. Designed for a maximum crew of seven, the Dream Chaser is a lifting body spacecraft based on NASA’s HL-20 crew vehicle, and will launch on an Atlas V.

The atmospheric drop test of the full-scale vehicle, expected sometime in the second quarter of 2012, will asses handling qualities as well as stability and control during an unpowered descent to a conventional runway landing. The design of the low-speed flight control system is being fine-tuned after drop tests of a scale model were conducted in December at NASA Dryden Flight Research Center from a helicopter hovering over the dry lakebed at Edwards AFB, Calif.

Preparations for firming up the drop test from WhiteKnightTwo, which will take place from an altitude of 45,000 ft., follow last December’s announcement that Virgin Galactic is supporting the Dream Chaser development. Virgin Galactic also was included in Sierra Nevada’s CCDev2 proposal. The large, four-engined carrier aircraft is in development for Virgin’s SpaceShipTwo sub-orbital space tourism and science vehicle, but is being actively marketed for a range of other “mothership” drop test roles.

New details of the Dream Chaser were revealed by Sierra Nevada Space Systems Group at the recent American Institute of Aeronautics and Astronautics Space Planes and Hypersonics conference in San Francisco. Integrated product team lead Russ Howard says the vehicle’s hybrid rocket motor is undergoing further development work following testing for CCDev, which included three static firings in one day. “This included one vacuum start and a demonstration of a new pressure feed system,” he says.

The rocket, fueled by a combination of hydroxyl-terminated polybutadiene (HTPB) and nitrous oxide, is designed “for flexibility, as it can be stopped, re-started and throttled to 100% for launch abort/escape, or 50% for fine control in nominal maneuvers. We’re planning to throttle down as low as 50%, but we have demonstrated thrust down to 30% and its been very stable,” Howard adds.

The Dream Chaser is expected to have a cross-range capability of 1,700 km (1,000 mi.) and with a subsonic lift/drag ratio of 4:0, a “landing will be feasible on 7,000-foot runways,” he says. However, with launches currently planned from Kennedy Space Center’s SLC-41 launch pad (and possibly SLC-39B after conversion), the primary landing site is Cape Canaveral’s 15,000-ft. main runway.

Beyond atmospheric drop tests, further development plans include an un-piloted orbital test flight (OFT-1) boosted by an Atlas V, followed by a crewed OFT-2. The system is aiming for initial operational capability in 2015.