The roar of a rocket motor at a test range in Texas seems to herald America's intent to launch people back into space. Built by SpaceX of Hawthorne, California, it's one of eight rockets that will be fitted into the conical flanks of the Dragon manned spacecraft. The capsule will allow for propulsive landings on Earth, the Moon or Mars as well as helping astronauts escape a fiery end if the rocket below them explodes.
The
motors are hypergolic, meaning that they spontaneously ignite when
their two fuels mix. Unlike a solid rocket motor that has to burn fully
like a firework, this allows them to be switched on and off at will.
Another advantage is that the fuels don't need to be cooled
cryogenically.
In the event of an accident, however, volatile hypergolic fuels can be extremely dangerous. In his book Empire of the Clouds, author James Hamilton Paterson relates the grisly aftermath of a World War II rocket-powered airplane crash. "The Komet's fulminating rocket fuels would explode spontaneously when mixed in even minute quantities and on one hideous occasion had actually dissolved a pilot alive before rescuers could free him from his crashed aircraft," he writes.
In the event of an accident, however, volatile hypergolic fuels can be extremely dangerous. In his book Empire of the Clouds, author James Hamilton Paterson relates the grisly aftermath of a World War II rocket-powered airplane crash. "The Komet's fulminating rocket fuels would explode spontaneously when mixed in even minute quantities and on one hideous occasion had actually dissolved a pilot alive before rescuers could free him from his crashed aircraft," he writes.
Since those early days,
aerospace engineers have learned a lot about hypergolic rocket motor
safety and SpaceX will no doubt have the tanks well protected.
If you enjoyed this post, watch a rocket sled eject a mannequin or see a nanorocket propel itself through liquid
http://www.newscientist.com/.
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