A View from David Zax
The Push-and-Pull of Rocket Science
A new type of escape system will alter the iconic look of the next generation of space rockets.
The United States’s space rockets are likely to look a little different, soon. Space Exploration Technologies (SpaceX) is developing a new launch escape system that doesn’t have a need for that iconic pointed booster tower that traditionally lugged crew capsules behind it in case of emergency. The old design is being rejected in favor of a new one–one that would push instead of pull, Paul Marks over at One Per Cent recently reported.
What’s the idea behind that pointy thing atop the launch capsule anyway? It’s a sort of insurance policy. What would happen if a rocket exploded on the launch pad? You’d want to immediately eject the crew capsule away from the carnage. The easiest and most aerodynamically sound way to do this, it seemed, was with that pointy-tipped set of rocket boosters above the crew capsule. So, at least, has gone the thinking, ever since the ’60s.
But it was always wasteful. For one thing, the bulky tower weighs the capsule down. And for another, its motors and fuel always wound up being dumped in the ocean somewhere. So people set to dreaming up new ways to whisk astronauts to safety in the event of a launch emergency. And the approach they’re arriving at is to push the capsule away, rather than pull it.
Boeing was in the lead on this idea, presenting the notion of a pushing system first at the Farnborough International Airshow in 2010. It was a clever idea, and solved the problem of wasting perfectly good engines.
And now SpaceX has decided to take that idea and riff on it. It even sold NASA on the idea, to boot–the agency recently awarded $75 million to make what SpaceX calls its “revolutionary launch escape system” a reality (the award derives from the Commercial Crew Development initiative, begun in 2009 to help private companies develop ideas into usable spaceflight tech). SpaceX’s approach differs from Boeing’s in that it plans to integrate escape engines into the side walls of its “Dragon” spacecraft. The side-mounted rockets will blast downwards in case of an emergency to propel the astronauts away from the inferno.
Furthermore, said SpaceX in its somewhat horn-tooting announcement, the system would provide crew with escape options throughout the entire flight, not just the beginning. And far from being relegated to the passive, auxiliary role of escape system, the side thrusters could actually become an active and integral part of a dynamic craft at other moments: “the same escape thrusters will also provide the capability for Dragon to land almost anywhere on Earth or another planet with pinpoint accuracy,” according to the announcement.
SpaceX’s Elon Musk has said he anticipates the first manned Dragon mission in 2014. Just be forewarned: at the launch, it may just look a little different from what you’re used to.
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