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No One Wins NASA Space Elevator Contest
volts writes "According to New Scientist no one was able to grab the two $50,000 top prizes in the recent NASA 'Beam Power Challenge'. The biggest limiting factor seemed to be that no team was able to meet the speed requirement, although a group from the University of Saskatchewan in Canada set the height record at 12 meters. Not quite geosynchronous..."
$50K for a design and prototype isn't a lot, but since student labor is basically free most of the money can go towards building the prototype. The biggest problem seems to be that the energy source available seems to be the light energy from a couple hundred watt lamp. Assuming that the bulb is 50% efficient that doesn't leave a lot of energy to move even the motors at the required speed, let alone the entire vehicle.
There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
Go back to steam engines, stirling engines? If your power source is light, why bother with electrical engines? Use some liquid gas as fuel in a tank, use the projected light as a heat source, let the gas heat up in a combustion chamber (a piston?) and drive the whole thing up as a locomotive :)
You can't handle the truth.
The point of the exercise is not to win $50,000. The idea is to give people an idea of what particular technologies NASA is looking to invest in.
NASA and other government agencies regularly offer research grants to develop the technology they want. This is just a way to do the same thing on the cheap. Rather than offering several different parties hundred thousand dollar research grants, you offer a prize to the winner of a contest, and hype up the contest. That way, people get fame as well as the possibility of millions of dollars in government contracts if they win.
That's what I thought. I was wrong.
The argument is reduced to spending for the sake of NASA jobs. Communism.
I suggest you read Slashdot
Actually what you "win" is licenseable technology that costs you $10 million less to develope and open the door to the posibility of getting the real "prize" which happens to be much larger (Also know as venture capital).
The minimum speed was 1 meter/s = 3.6km/h = 2.2369 miles/h. I can walk faster than that
Not straight up, you can't.
Geosynch is 35,786 km above sealeve according to wiki. At 3.6 km/h it would take over a year to get up to geosynch
True, but as gravity decreases, you accelerate faster per unit energy. I can't be arsed to actually do any math, but 1m/s at 1G is going to translate into significantly higher velocity the further out you go. Besides which, if you want to use the elevator primarily for moving materiel rather than personnel, a one-year turnaround might not be too bad; throughput is potentially more important than lag.
Even for personnel, that's on the order of time it took to sail from Europe to America via wind power, and people did that.
Reality has a conservative bias: it conserves mass, energy, momentum...
Short of a superconductor, practical wired power transmission is measured in hundreds or at best thousands of miles. Tens of thousands would be too much to hope for.
Totally unnecessary. If the capsule goes up at 1m/s, it will run 1km in 1000 seconds and 200km in 200,000 seconds, which is about 55.5 hours. At that distance the speed of the capsule can be raised by other means.
You can't handle the truth.
The top prize is 50K...deduct 50% for university overhead, about 12K for graduate student salary, 5K for professor salary, and you might have 8K for materials budget. What happens when you need a special diode that costs 2K?
It sounds like a great idea, they should sweeten the pot a little more (and I did RTFA, 100K won't be enough either).
"Who are you?" "No one of consequence." "I must know." "Get used to disappointment."
"$50K for a design and prototype isn't a lot, but since student labor is basically free most of the money can go towards building the prototype."
As a research professor with students who could have tried to build this thing, take my word for it that it's not enough money. I refuse to have my students doing someone else's research for free; I want to be able to pay them at least $10/hour + tuition remission. For an undergraduate at my fairly inexpensive institution, that's about $7K per quarter, and I'd need three of these. Add a $20K equipment budget and $5K for my time and we are at $46K.
So the budget is $50K. What's the problem? Just the obvious one that my chance of winning is quite difficult to estimate, but certainly way less than 100%. I'd put my expected return at around $5K. There may be institutions and individuals who can afford to expect to lose $41K for the prestige of doing good research and the prospect of future funding. I'm not one, so I'm out.
It doesn't appear that I am unique in these calculations.
By contrast, I just finished a NASA Phase I SBIR. $68,000 over 6 months, guaranteed. If I wanted to do space elevator research, I'd be way better off submitting an SBIR proposal than entering the contest: small up-front risk, higher expected return, better prospects of future funding.
Contests are run because there are often folks who overvalue them, so they are sometimes a cheap way to get things done at the expense of others.
Last I checked, the Sears Tower's Skydeck is right around 400 meters (quarter mile) off the ground. And they run one single elevator from bottom to top.
This has nothing to do with Otis or any other traditional elevator companies. You obviously do not understand the concept very well to compare the "space elevator" to a traditional elevator. The design philosophy is completely different. The only reason people call it a space elevator is that it lifts crew/cargo from one point to another following a path that is, for the lack of a better term, in the general direction of straight up.
Otis does not build elevators with fixed tethers. Throughout history, elevators have always been built as a big box hung on steel cables with a counter-weight on the other end. The cables get pulled by a motor, and transfers that motion to the big box.
If anything, the space elevator is envisioned to be more like a monorail: a fixed track and the box climbing along it.
Current estimates suggest that a space elevator will be deployed in 2045 or so. I lunar elevator could be done much sooner-and would have immediate practical value.
And yet Edwards, who designed probably the most calculated-out elevator, doesn't call for this.
Why? Elevators would have to pass each other. You'd have to have multiple running at a single time, transferring energy. You can't transfer over the length of the cable, so they could only transfer when close - which means a *lot* of cars going up and down. Plus, at least early-on, up traffic is much more in demand of the cable's stress than.
I actually disagree with him somewhat on this one (largely because regenerating the energy is so very important, not just from an operational-cost perspective given low beaming efficiency, but from a thermal standpoint as well), the cars will be quite expensive just to waste or scavenge for parts in orbit, cargo/passenger return to Earth via rockets is incredibly difficult, and the extra stress put on the elevator isn't too much if you time things right), but the points made are quite valid ones.
I personally would support partial energy recapture, with ultracapacitors or high density batteries storing the energy for discharge in small widened "passing zones" that have embedded conductor cables. You time the launches so that the most stressed section (the connection to earth, which needs to be tiny and where any increase in bearing load propagates strongly along the rest of the cable) only ever has one car on it at a time. The less stressed portions of the cable can bear multiple cars much better.
He's just being nice so my real father won't freeze him in carbonite and sell him for spice.
Actually, that's not true. with a space elevator, the overwhelming majority of the energy is wasted as loss. High coherency lasers with acceptable atmospheric frequencies have less than 1% wallplug to energy output efficiency; microwaves are far worse. Then there's the atmospheric losses, losses in the adaptive optics, and losses on the solar cells (not as bad as one might expect since the cells are optimized for a single frequency, but still not great).
:) So, in the case of a space elevator, *assuming* that climber production/reuse costs are cheap, the operation is mostly energy constrained. Energy being proportionally cheap...
The benefit in the case of the space elevator is that the cost in rocketry doesn't lie in fuel - it likes in production and maintenance. There's a common rule in rocketry that if your fuel costs are a major part of your operational costs, you're probably doing something right.
He's just being nice so my real father won't freeze him in carbonite and sell him for spice.
One thing is when you make a competition and throw some money at it, but as soon as you start making the rule that it has to be 50% better than what we got already. Then it's just a cheap way to get some willing students to try off their talent. The more this happens, the less jobs will they have to fill.
I'm not saying i don't approve, cause there must be alot of research coming out of this contest, but don't sell your soles too cheap.