Slashdot Mirror
After the X Prize
rscrawford writes "'Robert Bigelow, chief of Las Vegas-based Bigelow Aerospace, is apparently setting higher goals for private spaceflight endeavors with America's Space Prize, a $50 million race to build an orbital vehicle capable of carrying up to seven astronauts to an orbital outpost by the end of the decade,' according to Space.com. Anyone think it'll happen?"
...it's getting them down in one piece that's difficult.
A month after Duke Nukem: Forever goes Gold...
Having something go up to the edge of space and back is relatively easy compared to going into orbit then coming back down again.
For the technically minded, here's a short article with the specifics.
Which members of nsync and backsteet boys are going to be on it?
In a digital world there can be only one..
The one, the only, MrDigital.
Although the energetic requirements are an order of magnitude higher for orbital spaceflight, this $50 million prize is almost an order of magnitude higher than the $10 million X-prize. The economic payback seems higher as well, since there are lots more reasons (both reasearch and tourism) to go to orbit than there are in sub-orbital spaceflight.
Robert Bigelow, Astro-Gigalo.
Nothing as complex as the space shuttle is required to just get to an orbital complex and return with people. There are alot of people in the required spacecraft (7 vice 3), but both agencies have made simpler spacecraft that almost meet the requirements. Unfortunately for the X-Prize contestants, this prize would be many many times more difficult and would probably require a rocket and capsule idea (vice a very impressive airplane). The only reason I say this is because the difficulty in reentry (where a $50 million dollar prize isn't going to motivate people to spend $1 billion to be able to make an airplane reenter--like the space shuttle).
Well I don't reckon it's beyond possibility certainly. If the X prize is won next week then the sponsorship boost from the publicity could be astronomical, especially if passengers start to be taken up.
As for when people start dying, I reckon all the people likely to go up in the near future will be adults who are well aware of the risks they are taking and are more than happy to take their chances for the experience of flying into space. People die mountaineering, people die skiing. Lets try to keep some perspective.
Mention the Lord of the Rings one more time and I'll more than likely kill you.
Why is everyone complaining about this prize? Oh no, earth orbit, it's too hard! Let's just take our X-prize, go home, and never launch again. Waah waah.
WHAT THE HELL.
If anyone on the planet would say "wonderful, now we've got an incentive to get to the next stage", I'd think it would be the people here on Slashdot - but all of a sudden it's too difficult to reach orbit, with a fifty million dollar budget, in half a decade?
Did anyone really look at the X-prize and say "Oh, that's easy, no problem"? Then why are you looking at this and assuming it will be a problem? There's a lot of time to work on it and at least one group that's already a significant fraction of the way there.
If you think it's hard, okay, sure, no argument, it's hard - but how many times have you learned something new by practicing easy stuff over and over again? It's an opportunity to invent some new low-cost fabrication and launching techniques. It's research. And possibly, it'll even lead to true commercial spaceflight.
I think this is a fantastic turn of events. I can't wait to see who decides to tackle it.
Breaking Into the Industry - A development log about starting a game studio.
Really, the things holding us back from manned space exploration is lack of a reason to do it. If someone found out that you could manufacture CPUs that are twice as fast by doing it in zero-G, I'm sure Intel would have a space station within the decade. If you could make toothpaste that would get your teeth extra white while giving fresh breath that lasts for twelve hours by doing it in zero-G, P&G would have a space station within the decade. But none of these things are true. All the reasons for sending men into space mostly come down to "humans have an innate drive to explore", etc. It's true but that doesn't motivate investors to put together the many millions of dollars needed to do this. That's why governments do it: taxpayers have such low expectations of getting something in return for their tax dollars that governments can build space shuttles, the Big Dig, etc.
Of course, pretty soon we will have to have more manned missions to Mars to figure out what's going on over at Union Aerospace's secret research facility.
In the early 1990s research was done on quick turn around vehicles for low cost space access. Two very good articles by Dr. Jerry Pournelle are The SSX Concept and SSTO Revisited.
You may or may not agree with Dr. Pournelle, I sure don't, on a lot of things, but he's spot on about what happened to the SSTO concept, NASA got control of it, let a contract out to Lockheed to develop the X-33, spent a whole bunch of money and didn't produce any real hardware unlike the SSX project which spent 60 million dollars and produced a prototype that was able to take off and land twice with a 26 hour turnaround with a support crew of 14 and which also managed to land safely after a hydrogen explosion tore off part of the aeroshell.
cheap labor conservatives - they want to keep you hungry enough to be thankful for minimum wage.
Although the energetic requirements are an order of magnitude higher for orbital spaceflight, this $50 million prize is almost an order of magnitude higher than the $10 million X-prize. The economic payback seems higher as well, since there are lots more reasons (both reasearch and tourism) to go to orbit than there are in sub-orbital spaceflight.
The problem is that the increase in difficulty is far, far greater than the increase in either energy or delta-v required seems to warrant at first glance.
There are two regimes in which a rocket can operate. In one, the delta-v required for the mission is much lower than the exhaust velocity. In this scenario, fuel is only a small fraction of the total craft weight, and scales linearly with delta-v. This is the easy scenario, and it includes the X prize's "get a rocket to a relative altitude of 100 km".
The second regime, the hard scenario, is the one in which the delta-v required for the mission is much higher than the exhaust velocity. In this scenario, the craft weight is dominated by fuel, and the fuel-to-everything-else ratio goes up exponentially with delta-v. Truly exponentially, not the "this is a quadratic but I'm calling it exponential" variety that I see so often around here. Craft design goes from "really hard" to "damn near impossible" to "outright impossible" very quickly.
Ground-to-orbit is balanced right on the knife-edge of "really hard" and "damn near impossible", and that's only when we use multi-stage rockets. Reusable single-stage-to-orbit chemical rockets are well into the "damned near impossible" regime, even with the advanced composites we have now. If the earth was even a little heavier, we wouldn't be getting off of it with chemical rockets at _all_. Orbital velocity is about 8 km/sec, escape is 13 km/sec, and the highest-Isp chemical rockets have an exhaust velocity between 3 and 4 km/sec (with SS1 having one in the range of 2 or so).
There are ways that you can make the hard scenario marginally easier. One is to use multi-stage rockets, though that's generally pretty much _assumed_ past a per-stage mass fraction of 5:1 to 10:1. Another is to use high-Isp chemical fuels - but these make your craft far more expensive due to handling concerns, and in the limiting case this can even be counterproductive (H2 is a lousy fuel for anything that launches from deep in the atmosphere or under a lot of acceleration, due to low storage density and large tank size). Another is to use as small a craft as possible to take advantage of stress scaling laws, but a) that means an upper-atmosphere launch instead of a ground launch, and b) your minimum cargo weight places a lower bound on the craft weight.
The only realistic options for a 7-human manned craft are a big, expensive multi-stage chemical rocket with disposable boosters (because refurbishing to man-rated spec costs an insane amount of money), or an exotic craft with a high-Isp drive, to push the problem back into the "easy" regime. The only high-Isp craft we can build right now with the required thrust is one with a NERVA-style nuclear drive. A remotely laser-powered craft can work too, and we have a good idea how to build these, but full-scale engineering of these haven't been done yet. Orion is _too_ large scale, and would be even less popular than NERVA.
So, I don't expect any vehicle-based solution to be easy to build or cheap enough to run to make the prize offered a significant attraction.
A single-passenger craft would be much easier, due to reduced craft mass (materials scaling, again).