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Wednesday, 21 May 2014

The changing face of manned spacecraft


Image: 11976_16127_ACT.jpg
This image was taken during a series of wind tunnel tests for Blue Origin's Space Vehicle at Lockheed Martin's High Speed Wind Tunnel Facility in Dallas. The vehicle's biconic shape is designed to provide more cross-range and interior volume than a traditional capsule and weigh less than a winged vehicle.
NASA has signed contracts for commercial companies to design, build, and test commercial spacecraft that will be safe and certifiable for carrying NASA astronauts into space. Through these contracts there is constant feedback on how the competing designs are likely to meet the NASA requirements.
Apart from Lockheed Martin's Orion program, selected space transport projects include SpaceX's Dragon, Boeing's CST-100, and Sierra Nevada's Dream Chaser. The latter is the only spaceplane proposal within this NASA initiative, the others being space capsules. NASA has awarded contracts worth $3.5 billion for at least 20 replenishment missions to the ISS.
The Dragon made history in 2012 as the first private spacecraft to visit and dock with the ISS. This vehicle is designed for crew transportation and can carry up to seven crew/passengers. More testing is required before humans will fly on a Dragon mission, but work is progressing on the plan to undertake the first manned orbital mission in 2015.
The company’s other big program is the Falcon re-usable launcher family powered by the Merlin 1-D rocket. The Falcon 9 uses nine rockets. SpaceX is currently undergoing vertical takeoff/vertical landing tests in the form of one modified Falcon Stage 1 rocket, known as the Grasshopper, to evaluate and refine its performance. It is an essential part of an ambitious scheme to make the whole Falcon launch vehicle recoverable. Beyond the standard Falcon 9 will be an even larger Falcon Heavy rocket that is claimed to offer twice the launch capacity (in weight) of any existing launcher.
Elon Musk, CEO and Chief Designer at SpaceX, said that the intention was to recover the entire rocket and be able to re-launch the whole vehicle quickly. This has long been a dream for space planners, but so far the successful recovery and re-use of the whole space vehicle, and all its launchers, has been elusive. Maybe this aim is now getting closer. If so, the overall cost of commercial as well as exploratory science-based space missions could be seriously reduced.
Like the Dragon, Boeing’s CST-100 crew space transportation capsule is re-usable and can carry up to seven crew. It is intended to have a life of at least 10 missions and use a combination of parachutes and air bags to return to Earth. The first test is due in 2015. Detailed capsule design is currently being evaluated, with attention to the displays and controls, carried out at the company’s Houston Product Support Center.
Sierra Nevada’s Dream Chaser is the only winged spaceplane in NASA’s current evaluation program. At the end of last year, landing gear tests were carried out on the engineering flight-test vehicle. Launch will be on top of a booster rocket, but after the mission, recovery will be on a runway. Engine tests continue, including work on the reaction control propulsion system that will steer the vehicle in space and make small adjustments in directional thrust when docking with the ISS or other future stations.
Blue Origin offers another capsule space vehicle designed to carry up to four astronauts. A successful pad escape test was achieved in October 2012 at the company’s West Texas launch site and the vehicle flew up to 2307 ft under active thrust vector control before making a parachute descent to a soft landing. As a part of the re-usable booster configuration tests, a rocket chamber engine thrust firing also took place last October. The 100,000-lb thrust BE-3 engine is a liquid oxygen design.

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