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Japan starts space elevator experiments

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Re: Japan starts space elevator experiments

#131
post #4

The experiment sounds great. But should this work and a real cable to orbit is built, what happens when the cable snaps!? Can such a structure be made failsafe?

Some proposals include spacing charges along the cable to break it into small sections and enable it to come down more safely. Of course, this means lining your vulnerable cable with explosives, which seems like a bit of a design smell.

Re: Japan starts space elevator experiments

#132
post #94

Earlier quoted context omitted.

Thanks for the link. I'm personally very conflicted about patents. In this specific case I classify it as a "speculative" patent => I'm totally against this it. Patents should be allowed only for something that exists / can be demonstrated (which would ensure that patents are something somebody invested in, and therefore at least believed in).

Yeah, I wonder if anyone has patented human teleportation...

Don't patents only have a 20 year lifespan? If you patent human teleportation, and nobody actually develops it in the 20 year life of your patent (a prediction which is highly likely to be true), then you've simply wasted your filing fees, made a charitable donation to the patent office (and your patent attorney).

Re: Japan starts space elevator experiments

#133
I don't understand how a space elevator would be advantageous in terms of the energy required to get something to space. The load still has to reach orbital velocity.

Will the station at the end of the tether still need a rocket to deal with the additional mass? Is the fact that this rocket only has to go up once the core advantage?

Wouldn't the load going up the elevator pull the tether to one side?

Re: Japan starts space elevator experiments

#134

I don't understand how a space elevator would be advantageous in terms of the energy required to get something to space. The load still has to reach orbital velocity. Will the station at the end of the tether still need a rocket to deal with the additional mass? Is the fact that this rocket only has to go up once the core advantage? Wouldn't the load going up the elevator pull the tether to one side?

The station at the end is in orbit, so it's the difference between trying to climb a ladder to the Moon, and trying to jump to the Moon.

Re: Japan starts space elevator experiments

#135

I don't understand how a space elevator would be advantageous in terms of the energy required to get something to space. The load still has to reach orbital velocity. Will the station at the end of the tether still need a rocket to deal with the additional mass? Is the fact that this rocket only has to go up once the core advantage? Wouldn't the load going up the elevator pull the tether to one side?

Since rockets lack infinite thrust, they take a finite amount of time to reach space. While they're doing so, they need to fight gravity -- ~all the thrust that's directed downwards, as opposed to horizontally, is wasted energy.

There are more reasons to build a space elevator, but that's a big one. It really would be far more energetically efficient.

Re: Japan starts space elevator experiments

#136

Someone patented space elevators in 2015. http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=90858... No comments...

I think in this case there's so much "prior art" that the patent would be invalidated at the first challenge.

An organisation capable of building a space elevatoren surely would have the resources to fight a patent troll... Or just pay up some royalties that likely will be insignificant in the overall budget.

Re: Japan starts space elevator experiments

#137
> using six oval-shaped cars, each measuring 18m x 7.2m holding 30 people

Hmmm...is that 30 people/car or 30 people/6 cars? You will be enclosed with them on 18m x 7.2m, that's 120m², for 8 days!

The former case would sound like torture, in the latter case it could be done comfortably, though, but it would still require some good nerves by the travellers...

Re: Japan starts space elevator experiments

#138

I don't understand how a space elevator would be advantageous in terms of the energy required to get something to space. The load still has to reach orbital velocity. Will the station at the end of the tether still need a rocket to deal with the additional mass? Is the fact that this rocket only has to go up once the core advantage? Wouldn't the load going up the elevator pull the tether to one side?

I think the advantage would be that you only have to deal with dynamic forces the static force of gravity would not be a problem. The diffrance between a bridge and a helicopter.

Maybe the required energy would be sucked out of the earth's rotation, but that seams insane.

Re: Japan starts space elevator experiments

#139
Given enough investment, Stirling engines could beat internal combustion for many applications due to a theoretical efficiency advantage. However, economies of scale and many decades of R&D give internal combustion such a huge advantage, that this probably will never happen.

At what point does the 20 year amortized cost of a system involving a space fountain or launch loop acting as the 1st stage of a vastly simplified and downscaled rocket break-even with some small multiple of the 20 year amortized cost of a space elevator? I suspect that this multiple might be small enough that economies of scale and optimizations of other systems could keep space elevators out of the picture forever.

Re: Japan starts space elevator experiments

#140

It’s cool that any kind of space elevator experiment is happening at all, but temper your expectations with the numbers: this is a 10m cable. It is literally a 1:9,600,000 scale model of a real space elevator.

This isn't a scale model of a real space elevator at all.

From the article: Shizuoka University and contractor Obayashi aim to launch two small (10 sq cm) satellites connected by a 10m steel cable from the International Space Station.

I don't see any ways in which this is a space elevator related experiment.

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