Solar Drape Concept Would Take Advantage of Lower Gravity On The Moon

Doug Plata has proposed a solar drape concept for the moon. The moon has no wind and has one-sixth Earth gravity.

A large robotic rover would place telescoping towers on the moon and thin-film solar cells that are like drapes or rectangular banners.

There would be suspension lines between the towers and would be connected the solar drapes.

After all telescoping towers are placed they would rise at the same time and lift the wall of solar power into place.

48 thoughts on “Solar Drape Concept Would Take Advantage of Lower Gravity On The Moon”

  1. I like the idea of solar drapes–and towers/zip-lines to get around.

    To me–there should be a zip-line over Apollo 11, so tourists can hang low but not disturb the site.

    If the Moon is ever turned into a shell world–enclose all but that site–leave it in the vacuum.

  2. But now you’ve gone from a project that can power the initial settlements, to something that can be established after a settlement is up and running, mining is up and running, minerals processing is up and running, metallurgical refinement is up and running, and metal fabrication into fuel rods is up and running.

    And after someone has invented and developed the pure thorium reactor, which I think is just theory at this point.

  3. That’s another place where drapes would be useful: Around landing sites.

    Most of the energy transferred to debris will be on very shallow trajectories, a wall or drape around the landing site would stop almost all of it before it went very far.

  4. Subcritical reactors may solve that problem. Luna has some thorium. Or space-based enrichment of natural uranium ore may become practical with cheaper space launch. Nuclear power is what it is all heading toward. May as well get started as soon as possible.

  5. Right, and beware the tsunamis from the lunar maria.

    Many forms of nuclear power do not require water for cooling and heat exchange. Liquid metal cooled, molten salt reactor, gas cooled reactor etc.

  6. Regardless of the absence of Greta (or whomever takes her place on the stage once the inevitable scandal breaks out) on the moon: anti nuke considerations are still a major consideration at just about every possible launch site here on Earth.

    You can’t go on about nukes being allowed on the moon if you can’t get permission to launch them from a site in Florida.

  7. The cells are flat on the surface. If by “screen” you mean the transmitter mirrors, they are vertical wire mesh and should be almost unaffected by small sized dust coating. Criswell studied the visible levitating streams, so it seems he should have considered the problem, but I do not remember any mention of it in his papers(?). As to how dust affects collectors, I’m thinking they can be overbuilt fairly cheaply. Simply outgrow/(recycle) the dust coating may be the cheapest. The cells themselves are very thin.
    Also curiously, Peter Glaser was studying the range reflectors when he saw the intense sunlight in Space, and invented SPS.

  8. how much moon dust can accumulate until the screen is no longer effective? better not drive vehicles or land ships nearby.

  9. Dan is correct, the cold traps are colder than usual Lunar night temperatures, actually getting down to deep space temperatures where there is little exposure to reflected Sunlight.

  10. In the situation being discussed solar is superior to the various nuclear options, it’s simpler, lighter and cheaper for the power output. It wouldn’t be until power requirements got into the gigawatt range that nuclear would become a sensible alternative.
    The brain damage is yours, not ours.

  11. My first guess: should be similar.
    2nd guess: since it’s permanently shadowed, it may be colder.
    So this gives you an upper bound, at least.

  12. thank you for just stating truth… obviously in early days some other power sources will be needed for the immediate term but once able to build there . nuclear makes so much more sense in space ,, much more so than earth where it still makes sense

  13. My goodness, that Greta cult inflicted mass brain damage and memory loss on people. Let’s remedy that by stating a litany of the commonly known and obvious.
    — lunar surface environment has a two-week zero-sunlight phenomenon, commonly referred to as ‘night’;
    — sunlight is not available during the ‘night’;
    — people with advanced lunar geography delusions should be reminded that ‘peaks of eternal light’ are a misnomer (and SpaceX is at a known misnomer risk, after Tesla and its ‘autopilot’), as ‘night’ is merely shorter there, and the price for such a modest comfort is reduction of usable lunar surface to a patch the size of a small town;
    — nuclear power is the definitive solution to lunar power generation, invulnerable to space debris and a variety of radiation, which is fairly relevant and useful in lunar surface environment;
    — Luna has no atmosphere, therefore radiative cooling into ~20K sky will work even when sunlight is above, with proper and rather simple shielding;
    — well-designed nuclear generator can provide stable power for 20, 30 or 50 years, assuming that designers are not forced to use garbage-grade uranium, but use US Navy’s fuel enrichment level of ~97%;
    — there is no risk of ‘proliferation’ on Luna, whatever that nonsense means to people who mindlessly parrot it;
    — Luna is and shall remain Greta-free for the foreseeable future, hence there is no shame in flying a nuclear generator with a ~97% enriched core in there, in case that bothers anyone.

  14. Moon surface temp at night is 100K. There are a few superconductors with Tc > 100K, but it’s pretty borderline.

  15. I agree with Andrew. On Earth you need delta-v to change orbital planes. But on the Moon you can reach different orbital planes by just very minor adjustment of your trajectory from Earth. The difference in delta-v should be negligible.

  16. Curiously, David R. Criswell was studying this exact thing for NASA when he learned of the high amount of solar energy in Space/on the Moon. He then dreamed up Lunar Solar Power.

  17. Assuming H + O rockets, seems like a hard surface would both support the rocket and prevent (non-water) spray w/o the hills.

  18. There should be a measurement of this, how much has accumulated on the range reflectors placed by NASA in the 70’s. It may clear off as fast as it lands on an exposed surface, which solar cells would clearly be. Certainly a potential problem favoring L5 over Criswell for Earth power.

  19. There is the consideration of electrostatically levitated dust particles interfering with the panels. This is a solar driven event in which high voltages are generated by the UV light.

  20. Both Criswell and polar highland plans solve downtime with multiple collectors (or the rotating drapes) such that some are *always* (except eclipse) lit. Would the crater bottoms be cold enuf for ambient temp superconductivity? To connect these together and to load?

  21. Seems like the drapes would be in a gentle arc along a crater rim, perhaps leaning outward a little for balance, so the self-shadowing would be only a little, not all at once.

  22. My system should be simpler:
    It should be possible to just use a tripod or tetrapod so little or no excavation, with your system you require two end anchors.

    If a non-reusable lander is used it could form the core of the structure, easy to see something like a Falcon 9 booster with a few attachments.

    the structure would be cruciform with the arms supported by cables from the top of the tower, so not so much beefing up of the arms required.

    Going higher at the peaks of (near) eternal light reduces to time light is interrupted due to landscape shading

    using 2 or 3 towers spread out far along a ridge would reduce the time of light interruption.

  23. Polar landings require more Delta-V. More Delta-V means less mass landed.

    Sure there is supposed to be water there but there is a whole lot of moon elsewhere.

  24. I’m glad that you watched the video. Are you sure that your concept is the least mass / max power approach? Since the end of your arms are not being supported then the shoulders would need to be more beefy which means that the support structures would need to be more beefy. With my solar drapes concept, the support is largely due to the compressive force of the material within the towers.

  25. Good thoughts. No place, even at the poles, actually has 24/7/365 sunlight. So one would have to deal with the down time one way or another. One of the main power demands would be the electrolysis of water to produce propellant. Having a 3-day down time isn’t going to a big problem there. As for habitation, one would need power storage system. But that would be much like how they’ve solved that problem for the ISS which is out of the sunlight nearly 50% of the time.

  26. Yes, the animation indicates that the drapes are to be used at the poles where we are highly likely to go first. In the animation, at the top of the drapes there are motors which cause the drapes to track the sunlight along the horizon. In this way the power would be maximized with occasional self-shadowing being a modest problem.

  27. So there could be a synergy between the landing pads as animated and the solar drapes so that there wouldn’t be any regolith spray. Then one would either have to use the 1/r^2 for the exhaust gas and hence place the landing pad far enough away or place the landing pad behind a natural object such as a hill / crater rim.

  28. My animation advocated the use of solar drapes only in those polar locations where sunlight is 85+% of the lunar year. These areas can support hundreds of thousands of people. But as bases and settlements develop away from these sunlit peaks nuclear power would indeed be useful although others have ideas for how power from the sun could be stored.

  29. I agree, if you want continuous habitation then you must have nuclear. But solar would be useful for supplemental power and for powering construction equipment.

  30. In terms of keeping the light and heat on during the two week winter nuclear will win.

    Also, did your power/weight ratio factor in two weeks of batteries?

  31. Just one small problem is thatthe spray of rockets landing, or meteor impacts can travel around the moon and blast these full of tiny holes.
    I suppose they can be lowered during rocket events.

  32. Small thermoelectric units are ok, but bigger ones need plumbing , and plumbers with Ph.D’s

    in terms of power to weight ratio, the drapes will win.

  33. It is a good place to set up the transmitters, having slopes that provide a place for large apparent aperture as seen from Earth. Short cables to the *near* or close far side help cover new Moon situation. Very similar to the sides of the crater being close. Otherwise, half of the limb is bathed in sunlight, like half of the crater rim slopes.

  34. “. . . think of the limb of the Moon as being like the rim of a crater at the pole. Part of it is always in sunlight, ”
    I don’t know what you mean, there is no fixed limb with regard to the Sun.

  35. On a more abstract note, think of the limb of the Moon as being like the rim of a crater at the pole. Part of it is always in sunlight, except during eclipse. But different sides of it, so no panel is always lit, unless raised and rotated like the plan presented. It is the same basic question. I think building more simple panels is easier than trying to keep them lit 24. Or, use H. Or, just do it at L5. But then you have to build the sats. We need a plan energy companies will see as fundable.

  36. The trade off is between more solar panels on the sides of the polar ridge vs a contraption to lift the panels above the ridge, and rotate them. The bigger trade off is power beaming vs trying for 24 hr sun at one place. *Solving* the 24 hr problem may be worse than living with it.

  37. Why is this better than just putting the cells on the ground, UNLESS it is for a polar ridge, where both sides would work (at different times)? (edit: and the ridge itself is not lit on its slopes)

  38. Multi dozen kilometer “open air” LIGO observatory takes advantage of lunar vacuum and distance from Earth.

  39. OK, hadn’t watched the video. To avoid shadowing throughout most of the lunar day the spacing of the drapes would need to be large relative to their width.
    So I still prefer my idea

  40. The problem with that idea is that the Moon rotates, really it needs to be one rotating tower at one of the poles with extended arms.

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