6 ms·

Here is my hope (and my belief): the ultimate end here is orbital rings [1]. To summarize the video, you can put copper cabling in orbit, run a current through

by cletus 4y ago

Here is my hope (and my belief): the ultimate end here is orbital rings [1]. To summarize the video, you can put copper cabling in orbit, run a current through it and keep things in place (relative to a point on Earth) with magnetic levitation. The most important part of this is that you can have things in LEO that are fixed to Earth points. Why does this matter? No longer do you have to speed up to Mach 30 to reach orbital speeds. You could technically run a cable from 150km up and carry people and goods from Earth into LEO and back. This could revolutionize long-distance travel on Earth too. It's estimated that a space-based power collector could create about ~7 times the energy of an Earth based collector due to less power loss from the atmosphere and night (to be clear, a solar collector in orbit would still occasionally be occluded by the Earth but it won't be half the time). You can get power down to Earth in two ways: you can transmit it. This is actually viable but is not ideal. Alternatively, if you have an orbital ring, you can attach it to that and just run cables down to Earth. We use longer power transmission lines than that on Earth already. All of this requires no new physics, no magical materials (eg space elevators do) and are just (admittedly massive) engineering projects. If you can get solar panels into orbit for <$10/kg payload costs and run cables down to Earth, you'll solve the variance issue with solar and create cheap power on a massive scale. And none of this requires commercially viable fusion (which I'm not yet convinced will ever happen) or even the serious externalities of nuclear fission power. [1]: https://www.youtube.com/watch?v=LMbI6sk-62E&t=62s https://www.youtube.com/watch?v=LMbI6sk-62E&t=62s

thenewthotness 4y ago
I did a back of the napkin calculation a while ago regarding how many car lengths you’d need to put in LEO to have an unbroken traffic jam in orbit and the result was surprisingly comparable to the number of cars we’re currently producing. If you were “simply” launching wire instead I’m sure you could get enough material up there in much fewer launches. I’m curious as to how you would construct such a loop since you’d need to station keep it somehow while it’s inoperable.
- cletus 4y ago
  You can build it in sections because the wire itself is travelling at orbital speeds. That's actually what makes the whole thing work. Running a curent through that creates an electric field. You would probably encase the whole thing and contain it with a magnetic field. You would then build things on top of that casing.
jtbayly 4y ago
What kind of cable material do we have that can support its own weight for that many miles vertically?
- elif 4y ago
  My man said copper XD
- Schroedingersat 4y ago
  Copper is not strong enough, and steel isn't quite strong enough to hold itself up with constant cross section. Carbon fiber is, or you could just have a tapered steel or aluminum cable. The loop could be anything as it's under zero G. You'd need counterweights above it. You only get access to the equator without some kind of bizarro maglev hula hoop contraption which would level a country if anything went wrong, and the equator doesn't really need help with solar or solar storage as PV+CSP works quite well there.
lostlogin 4y ago
Going with what you’re saying, a better use of the tech would be to supply electricity to places that currents rely on generators. There are islands that use diesel generators md burn a mass of fuel where electricity could be beamed in, Rarotonga for example.
- AtlasBarfed 4y ago
  ... that wind solar battery can't do better?
- cletus 4y ago
  So I don't think fossil fuelds will completely go away. It's just that most use cases will be eliminated once there is a cheaper and equially suitable method of power generation. I strongly believe in the future of solar power in general because it's relatively low-tech and reliable. There are no moving parts (other than maybe turning an array to face the Sun while it moves across the sky but this isn't strictly required). So solar power can provide power in a lot of places where it's either impossible or infeasible to build infrastructure (eg remote places, war zones). But once solar power source (or something else) is cheaper than burning oil, gas or coal you can use that power to make fossil fuelds by sequestering carbon from air. That's not that difficult but we don't generally do it because it makes little economic sense. But this method would make fossil fuelds essentially carbon neutral. So there are vehicles that won't make sense to be replaced with EVs. Likewise, there are places where burning fuel may still make snese. Solar power may not make sense in jungles or hurricane zones so there may be continued use of generators. I can't speak to the specifics of Rarotongo. In general though, I think the technology and infrastructure will be truly transformative on a massive scale.
- grecy 4y ago
  Not just little islands either. I was at a radio transmitter[1] on the West Coast of Australia the other day. It's the largest low frequency radio in the Southern Hemisphere, used by subs and military stuff. The facility, which is 6 kilometres from a regular town, and has three diesel generators producing 18,000,000 watts of power, burns through 26,000 litres of diesel PER DAY. It's been doing that 24/7 since 1967. (There was a sign proudly stating as much) We do a TON of stupid stuff, regularly. [1] https://en.wikipedia.org/wiki/Naval_Communication_Station_Harold_E._Holt https://en.wikipedia.org/wiki/Naval_Communication_Station_Ha...
ilyt 4y ago
> All of this requires no new physics, no magical materials (eg space elevators do) and are just (admittedly massive) engineering projects. Dragging wire down from space to earth would require space-elevator level of tech. And I'm pretty sure microwaving earth's industry's worth of electric power thru the atmosphere wouldn't be any easier. Might even cause atmosphere warming all on its own.
var_cw 4y ago
wow this is such an incredible idea reminds me of the earth-moon fire pole https://what-if.xkcd.com/157/ https://what-if.xkcd.com/157/
- cletus 4y ago
  So this clearly wouldn't work but it is a fun thought experiment. Thing is, there are places that it would work. Pluto and Charon notably are tidally locked to each other and have muich lower gravity and much lower distance (~12K miles).
ben_w 4y ago
This will absolutely work (and unlike beamed power, can provably avoid being used directly as a weapon by malicious actors); but, when you get to the scale "chonky enough you can attach a cable down to ground level", you might as well just build on the ground in the first place. A few square meters cross section is enough for a global HVDC grid using boring copper and/or aluminium, the losses aren't worth caring about given how cheap PV is even now. Active support towers going up, that may work (if we solve the engineering issues, AFAIK nobody has tech demoed it yet), as those don't need to be supported by the cable, meaning the cable can be much smaller.
- Schroedingersat 4y ago
  Building up is vastly more difficult than hanging something. The best engineering on earth is still under a km in compression. To hang a steel cable 150km all you have to do is make it skinnier towards the bottom. The engineering issues of the bit at the top might be a bit eye-watering. A 100% reliable maglev sled supporting 100s of tonnes coasting on a catenary supported by centripetal force sounds like a recipe for the world's largest whip. Launch loops start to sound less scifi as a space megaproject (although then we're back tosuper weapons)

by cletus 4y ago

thenewthotness 4y ago

I did a back of the napkin calculation a while ago regarding how many car lengths you’d need to put in LEO to have an unbroken traffic jam in orbit and the result was surprisingly comparable to the number of cars we’re currently producing. If you were “simply” launching wire instead I’m sure you could get enough material up there in much fewer launches. I’m curious as to how you would construct such a loop since you’d need to station keep it somehow while it’s inoperable.

cletus 4y ago
You can build it in sections because the wire itself is travelling at orbital speeds. That's actually what makes the whole thing work. Running a curent through that creates an electric field. You would probably encase the whole thing and contain it with a magnetic field. You would then build things on top of that casing.

jtbayly 4y ago

What kind of cable material do we have that can support its own weight for that many miles vertically?

elif 4y ago
My man said copper XD
Schroedingersat 4y ago
Copper is not strong enough, and steel isn't quite strong enough to hold itself up with constant cross section. Carbon fiber is, or you could just have a tapered steel or aluminum cable. The loop could be anything as it's under zero G. You'd need counterweights above it. You only get access to the equator without some kind of bizarro maglev hula hoop contraption which would level a country if anything went wrong, and the equator doesn't really need help with solar or solar storage as PV+CSP works quite well there.

lostlogin 4y ago

Going with what you’re saying, a better use of the tech would be to supply electricity to places that currents rely on generators. There are islands that use diesel generators md burn a mass of fuel where electricity could be beamed in, Rarotonga for example.

AtlasBarfed 4y ago
... that wind solar battery can't do better?
cletus 4y ago
So I don't think fossil fuelds will completely go away. It's just that most use cases will be eliminated once there is a cheaper and equially suitable method of power generation. I strongly believe in the future of solar power in general because it's relatively low-tech and reliable. There are no moving parts (other than maybe turning an array to face the Sun while it moves across the sky but this isn't strictly required). So solar power can provide power in a lot of places where it's either impossible or infeasible to build infrastructure (eg remote places, war zones). But once solar power source (or something else) is cheaper than burning oil, gas or coal you can use that power to make fossil fuelds by sequestering carbon from air. That's not that difficult but we don't generally do it because it makes little economic sense. But this method would make fossil fuelds essentially carbon neutral. So there are vehicles that won't make sense to be replaced with EVs. Likewise, there are places where burning fuel may still make snese. Solar power may not make sense in jungles or hurricane zones so there may be continued use of generators. I can't speak to the specifics of Rarotongo. In general though, I think the technology and infrastructure will be truly transformative on a massive scale.
grecy 4y ago
Not just little islands either. I was at a radio transmitter[1] on the West Coast of Australia the other day. It's the largest low frequency radio in the Southern Hemisphere, used by subs and military stuff. The facility, which is 6 kilometres from a regular town, and has three diesel generators producing 18,000,000 watts of power, burns through 26,000 litres of diesel PER DAY. It's been doing that 24/7 since 1967. (There was a sign proudly stating as much) We do a TON of stupid stuff, regularly. [1] https://en.wikipedia.org/wiki/Naval_Communication_Station_Harold_E._Holt https://en.wikipedia.org/wiki/Naval_Communication_Station_Ha...

ilyt 4y ago

> All of this requires no new physics, no magical materials (eg space elevators do) and are just (admittedly massive) engineering projects. Dragging wire down from space to earth would require space-elevator level of tech. And I'm pretty sure microwaving earth's industry's worth of electric power thru the atmosphere wouldn't be any easier. Might even cause atmosphere warming all on its own.

var_cw 4y ago

wow this is such an incredible idea reminds me of the earth-moon fire pole https://what-if.xkcd.com/157/ https://what-if.xkcd.com/157/

cletus 4y ago
So this clearly wouldn't work but it is a fun thought experiment. Thing is, there are places that it would work. Pluto and Charon notably are tidally locked to each other and have muich lower gravity and much lower distance (~12K miles).

ben_w 4y ago

This will absolutely work (and unlike beamed power, can provably avoid being used directly as a weapon by malicious actors); but, when you get to the scale "chonky enough you can attach a cable down to ground level", you might as well just build on the ground in the first place. A few square meters cross section is enough for a global HVDC grid using boring copper and/or aluminium, the losses aren't worth caring about given how cheap PV is even now. Active support towers going up, that may work (if we solve the engineering issues, AFAIK nobody has tech demoed it yet), as those don't need to be supported by the cable, meaning the cable can be much smaller.

Schroedingersat 4y ago
Building up is vastly more difficult than hanging something. The best engineering on earth is still under a km in compression. To hang a steel cable 150km all you have to do is make it skinnier towards the bottom. The engineering issues of the bit at the top might be a bit eye-watering. A 100% reliable maglev sled supporting 100s of tonnes coasting on a catenary supported by centripetal force sounds like a recipe for the world's largest whip. Launch loops start to sound less scifi as a space megaproject (although then we're back tosuper weapons)