April 06, 2008
Don't need space elevators, just a rotating skyhook. You could orbit the bulk of the skyhook using laser launch and assemble it on-orbit, then spin it up using electric currents pumped through the tether or segments thereof. Fly a SpaceShipOne-class craft to a rendezvous with the end of the tether, clamp on, get flipped into orbit. Bonus points if the tether drops a similar craft (or industrial product like ultra-clear aerogels) just before the pickup.
"Is NASA becoming irrelevant for near Earth orbit launches?"
IMO yes. The costs can't be justified. Near Earth matters can and will shift to private companies unless government quashes access private access to space.
By analogy: I wouldn't expect NASA to be building executive jets or paving runways either. Yet the NASA charter allows them some role in aviation development.
Solar system exploration, observation, and analysis should be their space role. For jumping into space, landing, and putting various instruments into orbit NASA is no longer needed.
As for Space Elevators. Well, where are they? I suspect they exist where they will remain, in the imagination.
I'm still sticking by what I've been saying for some time. Man will never go into space in large numbers in our current form. Sometime in the future as robotic avatars, or with our conciousness downloaded into machines we may go into space.
Or we may just let our machines do the whole thing. And we can enjoy the fun parts if we want in realistic simulations.
But isn't this new trend for private space travel a symptom of the dramatic social stratification? For instance, the new upper class is so preoccupied with being special and original that instead of building yachts, they are building submarines (which are further isolated from ordinary humans) for themselves. The sub-prime situation had something to do with this incredible transfer of wealth. All the government deficit spending that was used to stop the economic collapse during the bear market of 2000-2002, actually ended up becoming the profits of the upper class.
"While the suborbital tourism project will provide a way for millionaires to buy a thrill I question whether it will play a significant role in a human migration into space."
Only in the same sense that prop-driven planes lead to jets. They proved the commercial viability, driving R&D and corporate investment.
Agreed that a CNT elevator would be great, but it's not the only method. Besides the skyhook I also like nuclear "light bulb" rockets (they use nuclear fuel to heat liquid hydrogen, but do not irradiate it, so it's a "clean" rocket) and heavy launchers (like the Sea Dragon) as technologies. Plus, getting a private sector company like SpaceX rather than NASA running a an access to LEO program will reduce costs a lot even with the same technology.
Having a fuel depot in orbit will also reduce costs quite a bit without having to change technologies greatly. The "easy" way to do that would be send fuel tanks up from Earth on a mass driver, but the harder (but radically more effective method) of refueling would be to mine the Moon or the asteroids. In space everything is worth its weight in gold as long as it has to be brought up from earth, but it's 16x cheaper to lift anything off the Moon. Bill Stone of Stone Aerospace has made his intentions to personally build a Lunar H2 mine within the next 10 years or so.
A couple things: "The step from suborbital to orbital flight isn't easy because reentry involves high temperature deceleration." Let's not forget that it also takes enormously more energy to get to orbit, versus just getting up to sixty miles.
Also, what SpaceX is doing is fundamentally different. They're building a commercial launch capability that does directly rival what NASA and other private and government sources offer around the world. SpaceX isn't a tour bus, it's a cargo ship, going all the way to orbit and back.