Rules Set for $50 Million America's Space Prize

An anonymous reader wrote in to say that The rules have been set for Robert Bigelow's $50 million 'America's Space Prize'. The gist of it is that the winner needs to get a crew of five people up 400km, complete two orbits of the Earth, and then do it again within 60 days. I've got a gremlin and a huge rubber band... now if I only had 4 friends!

Comments

Re:Technicality Smechnic..thingy

[logpoacher]

consider the fact that if you fired a bullet from a decent rifle a thousand miles up, it would go into orbit, but obviously bullets don't go into orbit here on the ground.

Well, careful here. That's the big misconception - that orbital velocity is anything like the speed of a bullet. Ok, ok, it depends on your definition of "decent rifle" :-), but no Earth rifle even comes close to firing at 5 miles a second - a tenth of that is more likely.

Similarly, SpaceShip One only achieved about 0.6miles/sec. That's why - amazing though it is that they achieved what they did on such a small budget - the orbit challenge is so much harder than just "touching space". When you consider that chemical rockets project propellant at about 2 miles/sec, you'll see that a single-stage rocket's mass must be almost entirely fuel (>85%) to achieve orbital speed alone - and that's after you've reached a suitable height! Multi-stage boosters help with the physics, of course, but they slaughter the economics. :-)

Anyway, achieving height is just the easy "Part 1" of the problem. Speed's the hard part. Try doing the momentum sums yourself - it gives you serious respect for people who can build machines to overcome the problems, and it shows how close Earth is to being completely un-escapable (at least using chemical rockets)!

Of course, re-reading your post, the rifle thing does illustrate your point rather well. Oh well ...