SpaceX carried out the test on Wednesday in Cape Canaveral, Florida, firing an unmanned test vehicle into the sky using in-built thrusters. The thrusters launched the Dragon capsule to a safe height, from which it landed softly in the Atlantic Ocean after deploying a system of three parachutes, writes Jonathan Amos for the BBC.
NASA contracts private space companies
Both SpaceX and Boeing have contracts with NASA for the development of vehicles which can take astronauts to and from the International Space Station. SpaceX plans its first manned flight in 2017.
As part of the contract the companies have to show that they have viable launch escape technologies to protect astronauts in case of accidents. SpaceX decided to use a “pusher” system on the Dragon, employing eight SuperDraco thrusters to launch the capsule to a safe height, before parachutes ensure a soft landing.
Although the only passenger was a dummy this time around, it gathered enough data for engineers to paint a picture of what a human being would have experienced. One side-effect were high g-forces, which astronauts are trained for.
Innovative pusher system improves on previous design
Previous abort systems have consisted of a tower placed on top of the capsule, which can pull it clear it rockets fail. NASA’s Mercury and Apollo programs used this system, as do the Russian Soyuz and Chinese Shenzhou.
These mechanisms need to be detached before the capsule reaches orbit, which is a major downside. Pusher systems are integrated into the capsule and do not need to be ejected.
“It’s the more sophisticated, modern approach. And in my opinion it’s also the safer approach to launch escape,” Hans Koenigsmann, SpaceX’s vice-president of mission assurance, said to the media. Boeing will also employ a pusher system in its CST-100 capsule.
Jon Cowart of Nasa’s commercial crew programme office, said: “We see no inherent problem with doing it this way. It’s innovative and that’s really part of the whole reason we’re doing commercial crew. Let’s learn to do business a new way.”
A pusher system also allows SpaceX to bring the Dragon capsules back to land after every use, using the in-built thrusters to control their descent.
