Lunar Spacecraft Compete For $2 Million NASA Prize

coondoggie writes "Nine rocket-powered vehicles will compete for NASA's $2 million, 2008 Northrop Grumman Lunar Lander Challenge, Oct. 24-25. The goal is to accelerate development of commercial Lunar Landers capable of bringing payloads or humans back and forth between lunar orbit and the lunar surface. NASA of course would expect to use some of the technology developed at the Challenge. To win the prize, teams must demonstrate a rocket-propelled vehicle and payload that takes off vertically, climbs to a defined altitude, flies for a pre-determined amount of time, and then land vertically on a target that is a fixed distance from the launch pad. After landing, the vehicle must take off again within a pre-determined time, fly for a certain amount of time and then land back on its original launch pad." Details about the teams involved with the competition are available at the X-Prize website. The event will be broadcast live via webcast next weekend.

Comments

Land? IRL?

[Tubal-Cain]

I am not ready to be landing spacecraft on the moon IRL. I can't even do it in the simulator

Re:I would have competed

[TheRaven64]

Low earth orbit is around 2000km up. Geosynchronous orbit is 35,786km above the Earth's surface. The height of the top of the stratosphere, which is about as high as you can get with a balloon, is 50km. It might be possible to get as high as 100km using a magic balloon. This would get you 5% of the way to LEO, or just under 0.3% of the way to geostationary orbit. The additional complexity of building something as massive as a balloon capable of getting a huge payload of rocket fuel to the edge of the atmosphere does not justify a 0.3% saving (closer to 0.1% in practice) in initial altitude. You can get a similar order of magnitude advantage without the additional complexity by launching from a large mountain.

If you want a multi-stage design, you'd be better off looking at jet and scramjet technologies than balloons. A jet is much more efficient than a rocket, because the reaction mass and the oxidiser are both taken from outside - it only needs to carry the fuel. Remember, in getting to orbit speed is more important than altitude. Escape velocity is around 11km/s. If you start from a jet at Mach 1, you are at 3% of this speed already. If you start from a jet at Mach 4 and then use a scramjet to get up to Mach 17 (the speed of X30) you are at 50% of escape velocity (70% of orbital velocity) before you leave the atmosphere. This reduces the size of the rocket needed by a huge amount.