Should we give up on the dream of space elevators? | Hacker News Reader

Should we give up on the dream of space elevators?

bbc.com

8 pointsdnetesn6 comments

> The Obayashi Corporation, one of Japan’s five big construction companies, last year published plans for a more robust space elevator carrying robotic cars powered by maglev motors similar to those used on high speed rail lines. These would carry humans making the required tether strength greater. Their design would cost $100bn, with transport costs down to $50-100 a kilogram.

That seems... incredibly cheap for a space elevator. Are they saying their design would cost $100bn total, or is that for the car only?

I would have guessed closer to the world's GDP, maybe a few orders of magnitude more.

What about instead of space elevator some sort of re-usable space launcher - i.e. a HUGE tunnel like contraption that basically propells a vehicle up and out of atmosphere without rockets but something else... - - think like a large hydrolic delivery system that goes x amount of miles from upper atmosphere and vehicle launches at whatever the velocity is to break out of atmosphere ? (I'm no rocket scientist obviously)

No.

http://en.wikipedia.org/wiki/Betteridge%27s_law_of_headlines

Why give up on something because we can't do it right now.

Yes. Because it's fundamentally flawed. You will not beat physics because you wish it. It will always take the same (relative) amount of power to escape earth velocity. Shunting some of the friction to entropy on substances (wear and tear) in sizes/lengths/stresses that are affected by atmosphere and space junk, leads to a more complicated and less reliable mechanism for transport. You STILL have to fight gravity and air resistance with an elevator. It's bought you NOTHING of value to build.

> It will always take the same (relative) amount of power to escape earth velocity.

Not really, most of the energy in a rocket launch is used to push the rocket fuel higher so it can be burnt to push the remaining rocket fuel higher.

If we could build a space elevator then the energy used to get a mass into space would be considerably lower since electric motors are much more efficient at lifting loads than rocket engines (and that assumes a mechanical method of lifting not some kind of mag lift system).

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