5 ms·

I wasn't a huge believer in this project when I was at Caltech, but I'm glad they stuck to it and are getting something off the ground. It's an interesting tra

I wasn't a huge believer in this project when I was at Caltech, but I'm glad they stuck to it and are getting something off the ground. It's an interesting tradeoff of RF losses vs losses to solar power non-ideality. The theory looks great, but I do wonder if the theory can be met in practice.

WalterBright 4y ago
If it works in Earth orbit, it will also work in lunar orbit where it can solve the most expensive barrier to a moon base - power. So, although it may be too expensive for Earth power, it can be very practical for moon power.
- dghughes 4y ago
  Wouldn't solar panels on the moon be easier? No atmosphere and on always being blasted with sunshine.
  - josh11b 4y ago
    There is no place on the moon that isn't in shadow 14 days at a time. https://caseyhandmer.wordpress.com/2022/07/03/powering-the-lunar-base-version-2/ https://caseyhandmer.wordpress.com/2022/07/03/powering-the-l...
    - amelius 4y ago
      Near the poles?
      - Fordec 4y ago
        Only works if your bases are at the poles. Which for some missions works, but it's a limitation if your project needs to be anywhere else.
        Nomentatus 4y ago
        https://futurism.com/the-byte/harvard-super-tall-towers-power-moon-base https://futurism.com/the-byte/harvard-super-tall-towers-powe... There's a famous-in-the-area ex-NASA blogger with good (not perfect) articles on the topic, but I can't Google and find him 'cause authoritative institutions now seems to trump and drown out mere experts on Google. Others here cite him: https://caseyhandmer.wordpress.com/2019/08/17/blog-series-countering-misconceptions-in-space-journalism/ https://caseyhandmer.wordpress.com/2019/08/17/blog-series-co...
    - TaylorAlexander 4y ago
      Maybe use solar panels to split lunar ice water in to hydrogen and oxygen, then use that to run fuel cells in the dark periods.
      - LarryMullins 4y ago
        14 days of lunar night would get quite cold. Maybe you could use the bases' water tanks as thermal batteries.
    - Nomentatus 4y ago
      Tall lunar pole towers: https://futurism.com/the-byte/harvard-super-tall-towers-power-moon-base https://futurism.com/the-byte/harvard-super-tall-towers-powe... Maybe better: nuke the moon and reduce a few key crater rims, then use much shorter towers. Could be that a series of regular bombs might be more effective and less likely to "alarm the horses (general public.)"
    - ehnto 4y ago
      Given the satellites need to be geostationary, don't they have the same issue? I know due to the higher altitude you would get more time in the sun but I feel like even one to two days would be too much distruption (2 days battery storage would be crazy expensive to send up but maybe that equation changes one day)
    - napier 4y ago
      Beam the power around the moon from where it's sunny at any given time to wherever needs it, using phased array orbital substation reciever-transmitters. No atmospheric interference to result in high rates of transmission loss. Might prove cost efficient.
  - JumpCrisscross 4y ago
    > Wouldn't solar panels on the moon be easier? Dust.
    - nakedrobot2 4y ago
      there is no wind on the moon.
      - JumpCrisscross 4y ago
        > there is no wind on the moon There is near a Moon base, which is presumably where you’d need power.
        ben_w 4y ago
        "Near" is a relative term; 10 km is a rounding error for resistive losses even in a mediocre cable at unspectacular voltages, even 1000 km isn't much loss for an HVDC cable, and it's economically reasonable to loop the moon with a 600Ω conductor if SpaceX's Starship price estimate works out.
        JumpCrisscross 4y ago
        I was going to rebut with distance and maintenance, but it's a hell of a lot easier to go 10km over than 10km up. (I think?) > it's economically reasonable to loop the moon with a 600Ω conductor Could you generate nontrivial power from the Moon's motion through the Earth's magnetic field?
        WJW 4y ago
        My gut feeling says that it is not impossible but you would probably need many loops around the moon to generate a sufficient coil, making the whole thing cost prohibitive. You could probably dot some solar farms around the equator of the moon and loop them all up with a big cable for a fraction of the price.
        ben_w 4y ago
  - dirkc 4y ago
    Two reasons I can think of 1. A moon day is 28 earth days, thus 14 days of darkness 2. Ice are in permanently shaded areas near the poles of the moon, it might be easier to setup satellites to beam down power rather than setting up in 2 locations
  - elil17 4y ago
    In addition to what others have said, it takes more fuel/energy to land a payload on the moon than it does to orbit one.
- sveme 4y ago
  Why not use classical PV on the moon? Too much dust?
  - dahfizz 4y ago
    Moon nights last 14 days. Not an option with current battery tech.
- colineartheta 4y ago
  If I recall, the current plans for the Artemis base is a small nuclear reactor.
- aerophilic 4y ago
  Love this concept… one issue however if I remember correctly is that it is pretty costly (fuel wise) to keep anything in lunar orbit. The issue is that the moon is very “lumpy” causing you to have to constantly correct your orbit. However maybe this is a non-issue if you are in a high enough orbit… but then you are trading how much power you can get to the surface.
  - gpm 4y ago
    There are a few "frozen orbits" that are stable: https://science.nasa.gov/science-news/science-at-nasa/2006/30nov_highorbit/ https://science.nasa.gov/science-news/science-at-nasa/2006/3...
    - moffkalast 4y ago
      Yeah and the LRO has been in one of them for 13 years now. It does restrict you quite a bit though. For Luna it doesn't make as much sense as it would for say Mars, since there's no atmosphere to reduce efficiency and no shortage of ground real estate. You can save a bit of propellant to not bring the panel assembly down, but you'll need fuel for orbital stationkeeping instead anyway.
      - dylan604 4y ago
        With the proposed "cheapness" of Starship $/kg, wouldn't sending fuel to refill the station keeping abilities be feasible?
- politician 4y ago
  It would also work well on Mars due to the thin atmosphere and closer orbit, and the Venusian Cloud Cities. The latter being particularly useful because you don't have to waste the extra weight of power generation infrastructure on your colony's living surface. For the Moon and Mars, it's amazingly useful to have your power generation infrastructure deployed globally ahead of time.

WalterBright 4y ago

If it works in Earth orbit, it will also work in lunar orbit where it can solve the most expensive barrier to a moon base - power. So, although it may be too expensive for Earth power, it can be very practical for moon power.

dghughes 4y ago
Wouldn't solar panels on the moon be easier? No atmosphere and on always being blasted with sunshine.
- josh11b 4y ago
  There is no place on the moon that isn't in shadow 14 days at a time. https://caseyhandmer.wordpress.com/2022/07/03/powering-the-lunar-base-version-2/ https://caseyhandmer.wordpress.com/2022/07/03/powering-the-l...
  - amelius 4y ago
    Near the poles?
    - Fordec 4y ago
      Only works if your bases are at the poles. Which for some missions works, but it's a limitation if your project needs to be anywhere else.
      - Nomentatus 4y ago
        https://futurism.com/the-byte/harvard-super-tall-towers-power-moon-base https://futurism.com/the-byte/harvard-super-tall-towers-powe... There's a famous-in-the-area ex-NASA blogger with good (not perfect) articles on the topic, but I can't Google and find him 'cause authoritative institutions now seems to trump and drown out mere experts on Google. Others here cite him: https://caseyhandmer.wordpress.com/2019/08/17/blog-series-countering-misconceptions-in-space-journalism/ https://caseyhandmer.wordpress.com/2019/08/17/blog-series-co...
  - TaylorAlexander 4y ago
    Maybe use solar panels to split lunar ice water in to hydrogen and oxygen, then use that to run fuel cells in the dark periods.
    - LarryMullins 4y ago
      14 days of lunar night would get quite cold. Maybe you could use the bases' water tanks as thermal batteries.
  - Nomentatus 4y ago
    Tall lunar pole towers: https://futurism.com/the-byte/harvard-super-tall-towers-power-moon-base https://futurism.com/the-byte/harvard-super-tall-towers-powe... Maybe better: nuke the moon and reduce a few key crater rims, then use much shorter towers. Could be that a series of regular bombs might be more effective and less likely to "alarm the horses (general public.)"
  - ehnto 4y ago
    Given the satellites need to be geostationary, don't they have the same issue? I know due to the higher altitude you would get more time in the sun but I feel like even one to two days would be too much distruption (2 days battery storage would be crazy expensive to send up but maybe that equation changes one day)
  - napier 4y ago
    Beam the power around the moon from where it's sunny at any given time to wherever needs it, using phased array orbital substation reciever-transmitters. No atmospheric interference to result in high rates of transmission loss. Might prove cost efficient.
- JumpCrisscross 4y ago
  > Wouldn't solar panels on the moon be easier? Dust.
  - nakedrobot2 4y ago
    there is no wind on the moon.
    - JumpCrisscross 4y ago
      > there is no wind on the moon There is near a Moon base, which is presumably where you’d need power.
      - ben_w 4y ago
        "Near" is a relative term; 10 km is a rounding error for resistive losses even in a mediocre cable at unspectacular voltages, even 1000 km isn't much loss for an HVDC cable, and it's economically reasonable to loop the moon with a 600Ω conductor if SpaceX's Starship price estimate works out.
        JumpCrisscross 4y ago
        I was going to rebut with distance and maintenance, but it's a hell of a lot easier to go 10km over than 10km up. (I think?) > it's economically reasonable to loop the moon with a 600Ω conductor Could you generate nontrivial power from the Moon's motion through the Earth's magnetic field?
        WJW 4y ago
        My gut feeling says that it is not impossible but you would probably need many loops around the moon to generate a sufficient coil, making the whole thing cost prohibitive. You could probably dot some solar farms around the equator of the moon and loop them all up with a big cable for a fraction of the price.
        ben_w 4y ago
- dirkc 4y ago
  Two reasons I can think of 1. A moon day is 28 earth days, thus 14 days of darkness 2. Ice are in permanently shaded areas near the poles of the moon, it might be easier to setup satellites to beam down power rather than setting up in 2 locations
- elil17 4y ago
  In addition to what others have said, it takes more fuel/energy to land a payload on the moon than it does to orbit one.
sveme 4y ago
Why not use classical PV on the moon? Too much dust?
- dahfizz 4y ago
  Moon nights last 14 days. Not an option with current battery tech.
colineartheta 4y ago
If I recall, the current plans for the Artemis base is a small nuclear reactor.
aerophilic 4y ago
Love this concept… one issue however if I remember correctly is that it is pretty costly (fuel wise) to keep anything in lunar orbit. The issue is that the moon is very “lumpy” causing you to have to constantly correct your orbit. However maybe this is a non-issue if you are in a high enough orbit… but then you are trading how much power you can get to the surface.
- gpm 4y ago
  There are a few "frozen orbits" that are stable: https://science.nasa.gov/science-news/science-at-nasa/2006/30nov_highorbit/ https://science.nasa.gov/science-news/science-at-nasa/2006/3...
  - moffkalast 4y ago
    Yeah and the LRO has been in one of them for 13 years now. It does restrict you quite a bit though. For Luna it doesn't make as much sense as it would for say Mars, since there's no atmosphere to reduce efficiency and no shortage of ground real estate. You can save a bit of propellant to not bring the panel assembly down, but you'll need fuel for orbital stationkeeping instead anyway.
    - dylan604 4y ago
      With the proposed "cheapness" of Starship $/kg, wouldn't sending fuel to refill the station keeping abilities be feasible?
politician 4y ago
It would also work well on Mars due to the thin atmosphere and closer orbit, and the Venusian Cloud Cities. The latter being particularly useful because you don't have to waste the extra weight of power generation infrastructure on your colony's living surface. For the Moon and Mars, it's amazingly useful to have your power generation infrastructure deployed globally ahead of time.