dimarts, 29 de gener de 2013

Make Life multi-planetary

Elon Musk: But the main thing —the goal I still believe in for the long term— is to make life multi-planetary.
Chris Anderson: And Dragon, the spacecraft you berthed with the International Space Station (ISS) in May, has features that might eventually prepare it for a manned Mars mission.
Musk: Eventually, yes. The thrusters on Dragon are sized so they’ll be able to do launch escape—which means being able to move away from the rocket at a force of approximately 6 g’s. That same thrust level happens to be kind of a good number for supersonic retro-propulsion for landing on Mars.
Anderson: Could you have sent Dragon to Mars instead of the ISS?
Musk: Well, it would have gone very slowly—and when it arrived, it couldn’t have landed. It would have made a crater.
Anderson: The issue is stopping once you get there.
Musk: Version two of Dragon, which should be ready in three years, should be able to do it. But really, if humanity is to become multi-planetary, the fundamental breakthrough that needs to occur in rocketry is a rapidly and completely reusable rocket. In the absence of that, space transportation will remain two orders of magnitude more expensive than it should be.
Anderson: Really?
Musk: Imagine if you had to have a new plane for every flight. Very few people would fly.
Anderson: Isn’t the fuel a huge portion of the expense?
Musk: The cost of the propellant on Falcon 9 is only about 0.3 percent of the total price. So if the vehicle costs $60 million, the propellant is maybe a couple hundred thousand dollars. That’s with rocket propellant-grade jet fuel, which is three times the cost of normal jet fuel. That’s using helium as a pressurant, which is a very expensive pressurant. A next-generation rocket could use cheaper fuel and also be fully reusable.
Anderson: Are you making an announcement right now?
Musk: I hope we might unveil an architecture for that next year. I’d like to emphasize this is an aspiration for SpaceX—I’m not saying that we will do it. But I believe it can be done. And I believe that achieving it would be on a par with what the Wright brothers did. It’s the fundamental thing that’s necessary for humanity to become a space-faring civilization. America would never have been colonized if ships weren’t reusable.
Anderson: Wasn’t the space shuttle reusable?
Musk: A lot of people think it was reusable—but the main tank was thrown away every time. Even the parts that did come back were so difficult to refurbish that the shuttle cost four times more than an expendable rocket of equivalent payload capability.
Anderson: It’s like sending Columbus’ ships out and bringing the lifeboat back.
Musk: We’ve begun testing reusability with something called the Grasshopper Project, which is a Falcon 9 first stage with landing gear that can take off and land vertically.
Anderson: A huge rocket, landing on its feet? Holy shit.
Musk: Yeah, holy shit. The stages go to orbit, then the first stage turns around, restarts the engines, boosts back to the launch site, reorients, deploys landing gear, and lands vertically.
Anderson: It’s like something out of a movie or my old Tintin books. It’s the way space was supposed to be.
Musk: Exactly.