…could cloud our lunar ambitions.
Outside of transportation costs (which will be coming down), this is probably the biggest barrier to lunar development. It's really nasty stuff. https://t.co/aWWNanCABG
— SafeNotAnOption (@SafeNotAnOption) May 20, 2019
Lunar Dust Storms…? ? I was interviewed here about Brian O’Brien, his Apollo Dust Detector Experiment, and how he solved (IMO) the long-standing mystery of lunar dust coating the Surveyor 3 spacecraft. This is a very fun read. https://t.co/cM4XgfUHsX
— Dr. Phil Metzger (@DrPhiltill) May 20, 2019
Lunar concrete is one option for turning a landing area into a nice clean parking lot.
New Scientist article
Four men on the moon by 2020? It’s not a typo. The article is from 2008, although it may foreshadow my idea of getting us there in 2020 by taping a microfilm of Trump’s tax returns to another Beresheet lander mission to goad congressional Democrats into passing a hundred billion dollar budget for a manned return mission prior to the 2020 election.
Another option is to spread something akin to a drop cloth or outdoor carpet, and note that outdoor carpet could also be used as a putting green.
Then there’s the idea of making a mobile solar concentrator that melts the top surface into glass, covering over a billion years worth of regolith bombardment. Though quite a bit low in sodium oxide, regolith’s mineral composition isn’t very much different from soda-lime glass, at least once you remove the slight excess of oxides of iron, aluminum, and titanium.
And of course many electrostatic and electrodynamic methods of dust control have been tried out in the lab with pretty good success. Some simple repel, but a simple 3-phase AC system can move the levitating dust along like a linear motor. Most focus on repelling the dust, but I’d also suggest using them in combination with electronic dust attractors that could be used like mosquito traps.
A mylar picnic tent over a landing site might also help with things, blocking both the solar wind and UV radiation. If the tent was bordered with dust traps to block dust from drifting in, or simply used a short plastic fence, it might ameliorate some of the problems.
I like the lunar concrete idea, especially if it uses all in situ resources. My idea for future lunar landings and takeoffs would involve a 180 mile long runway (with two 50 foot overruns). Landing spacecraft would come in at a very shallow approach angle. It would have a 193 ft/sec vertical velocity component to kill off just before touchdown, requiring about 40 lb of NTO/MMH per ton of vehicle weight. The remaining 5,500 ft/sec would be taken out by an electromagnetic decelerator, in which the lander is the armature of a linear motor. The reverse of that would be used in takeoff. It only requires 0.5 g to slow down withing this distance, or conversely to speed up during takeoff (refused takeoffs and landings are also possible). Make the runway 2.5 miles wide, and the centerline would be in the “dust safe” zone described in the article.
That’s a great article, BTW. Thanks for posting, Rand.
Oops, omitted the assumed approach angle. I used 2 degrees.
There are plenty of interesting approaches once they get enough infrastructure for landing strips and electromagnetic mass launchers. There are some fascinating concepts for giant orbital tethers, almost like trapezes, that basically pick up or set down lunar capsules as they go spinning by.
A few years ago, either here or at Selenian Boondocks, I came up with a way to use conventional LH2/LOX rocket engines without losing any propellant. The idea was that instead of a mass driver, the vehicle accelerates down a horizontal track using a rocket motor, but the track is inside a tubular tent, like a long fabric tunnel that can withstand a very small bit of internal pressure. The thrust from the rocket all kicks backwards (a lunar vehicle never gets close to the exhaust velocity of a cryo propellant, and the exhaust all stays in the tube. The vehicle will exit the tube long before the exhaust catches up to it through normal pressure-driven air flows, so the end of the tube can be sealed after launch, sealing in all those hydrogen and water molecules for condensation and re-use. Of course the start end of the tube would probably be beefed up because it actually has some serious exhaust to deal with and no good place to put it.
A similar trick might work for landing, corresponding to your electromagnetic braking system. If so, the vehicle would still have to have the mass ratio it would otherwise need, but the fuel expended on deceleration would end up in the base’s stockpile of water.
There’s also a really crazy way to slow down a vehicle flying a nice, linear, constant altitude path, which consists of a lot of little “catapults” hurling up little slugs of mass in its path, slamming into an armor plate. The slugs would make inelastic collisions due to their speed, and by conservation of momentum would slow the ship. However they’d also be imparting a whole lot of heat to the armor plate.
For a 10,000 kg vehicle coming in at 5,500 fps, tossing up 1 pound slugs every 90 or so feet would slow it at 0.5 G’s, making a 60 Hz buzz. The slug guns would gradually be spaced closer together farther down the track.
If you’re really up for some violence, you could probably provide lift for the vehicle by hitting the bottom with bullets. Everything would be automatically triggered, of course.
I’m not sure a crew would want to ride one, but it might work for payload deliveries. The energy efficiency would be pretty good, too. To cut the vehicle’s velocity in half, it would need to impact an equal mass with zero horizontal velocity. But if that equal mass is a bunch of slugs being tossed twenty or thirty feet in the air, then the total energy imparted to those masses would only be that needed to launch the vehicle the same height as the path. Suppose that’s 60 feet, and the vehicle weight 10,000 kg. PE=mgh for the moon says that it would take about 300,000 Joules, which over the two or three minute deceleration rate, would need about 3 horsepower to deliver.
The big advantage of such a system (which might be a bit unworkable from the ballistic impact and heating perspectives) is that it doesn’t require close contact. It could be set up to make those impacts at an altitude above the surface of 20 feet or 100 feet, depending on the path predictability of the vehicle because it would take several seconds for the slug to reach its apex.
But since each slug gun could be solar powered and physically separate from neighboring guns, it wouldn’t require massive leveling and dozing operations, long wiring runs (guns could communicate to each other and sensors via RF), and most importantly could be laid along an undulating surface without affecting the vehicle’s required path. Guns in valleys just shoot sooner and higher than the guns on the ridges, where valley and ridge aren’t all too different in height.
I’m sure it’s been looked at before, although the renewed interest might mean dusting off some of those wild ideas floated in the 60’s, 70’s, and 80’s.
The old Moon Miner’s Manifesto had quite a lot of ideas, but also the belief that true communism would finally work on the moon, which was pretty hilarious.
Why use only 0.5 g? At 3g for one minute the distance is only about 50km. Why use concrete? Sift the dust for large rocks and replace it. Use downwards lifting “dustfoils” to hold the craft on the surface and decelerate it.
A problem we wont ever solve without going but still a major hurdle that is mostly overlooked in the race to propose alternative routes to get back to the Moon.
That Wired article was a slog to get through. Maybe it said but did astronauts have problems with lunar dust after they left the Moon? Would it stick around on reusable vehicles and contaminate their space based counterparts?
Oh yeah!
If not for the expense, if they don’t come up with some good cleaning methods they might be better off leaving their suits on the surface or chucking them out an airlock in LLO. The dust is apparently right out of “A Cat in the Hat.” For a few missions it might be manageable, but for extended re-usability it will have to be dealt with.
But would the dust tag along on a lunar ascent vehicle? I am curious as to how big a problem the dust would be to a station like Gateway. Even if dust was mostly outside, astronauts would still have to do some spacewalks. Over time, the dust could be a significant problem.
There’s a professor in Tokyo that has done a lot of great work on using electrostatic and magnetic forces to deal with lunar regolith. It’d be cool to see some of his technology put to the test.
~Jon
It would be especially cool to apply those technologies to a colloidal thruster, and use lunar regolith directly as propellant.
If it’s the same researcher (and how many researchers are working in the field of lunar dust control?), his approaches to cleaning space suits was also interesting. One of the problems that all his methods had was dust that gets in between the suit’s fibers. Everybody knows that’s why Storm Trooper armor isn’t covered in fabric! ^_^
Those silver suits from Mercury and Lost In Space might be useful, too.
I saw another paper that repelled the dust with electrode whiskers about an inch long charged to about 1,500 volts, and they worked to repeal about 100% of the dust.
Of course, being from a coal mining region, I’d say just get used to the dust and retire on black lung payments.
Something else I wonder about is whether the regolith could be mechanically or chemically altered to make it less susceptible to the UV and solar wind problems (such as by consolidating it into bigger particles or giving them a thin lightweight coating), and then spraying a fine layer of it back on the surface around the work area. Basically, just bury under better dirt, without having to haul that better dirt to the moon.
A third option, once you’re landing multiple ships, is to make some of the expendable parts of the landers out of a thermoplastic that can be melted and used as a bonding agent, similar to mixing the regolith with an epoxy to make a type of concrete. However, I’m not sure how much mass it would add to the vehicle to substitute high performance alloys and plastics for what is probably going to be a much lower performance plastic.
However, that wouldn’t solve the problem of the dust moving across long stretches of the surface, kind of like blowing sands.
For takeoff reverse the dustfoils and lift the craft out of the surface. Fire dust at a nozzle/pusher plate on the back to accelerate. At 3g only 50km to travel. Could use higher acceleration I think.
Alternatively just use a mass driver track.
One option in mining lunar water is to mine the top couple inches of dust.
But we have to explore the lunar polar region to determine how and if lunar water is ecomonical to mine.
And no government would be capable of doing this (no government can mine anything on Earth- anyone imagining one easily mine water and make rocket fuel on the alien world of the moon, is delusional. It could harder than making a cell phone or PC. But even if a walk in the park, government is not capable of doing it.
North Korea runs plenty of government mines, and quite cheaply, too. Their miners are already be inured to starvation and primitive conditions, greatly easing supply and support requirements.
One big problem I haven’t seen addressed is that the bottom of Shackleton crater, and I assume most of the other good candidates for water ice, hover at around 88 degrees Kelvin, and there is no “warm side” anywhere. It’s going to be similar to conditions on one of Saturn’s airless moons, and the thermal environment will pose some challenges.
However, since those sites aren’t bombarded with UV radiation and solar wind (though I’m not sure on that), they might not have the dust problems found elsewhere.
But in terms of exploring the moon, we did it before, and we “should be” able to do it, and with advantage of past experience. One could give crew a mask, this time. Etc.
I remember a proposal for a “wtaer lock” to deal with the dust (on Mars and Moon). A U-shaped tunnel connected the inner airlock (with door into hab) to the outer chamber with surface exit. The tunnel was to be filled with water, with the vacuum end surface covert with an inter fluid floating atop the water to prevent it from boiling away into the vaccuum. The dust would wash off the suits into the water, then be filtered out. This would work better if the suits had an inert, non-fiber integument (basically an outer garment, sort of a space raincoat).
I am amazed by the sheer volume and creativity of all the ideas for dealing with Moon dust and all of the other challenges associated with living on the Moon and doing something productive while there. It strikes me, though, that all of these solutions are a bit janky and untested and are not the easy cure all that people imagine them as
The optimism is great though, great energy.
I hope people realize that this means we are a long ways, many decades, off from colonies, mines, large bases, ect ect. Perhaps coming up with ideas that get humans back to the lunar surface as quickly as possible isn’t the most important thing when considering the medium term, not even the long term, advancements that need to be made.
” . ..sort of a space raincoat).
How about booties, leggings, velvo, and use thin plastic , like a disposal tarp.
And you remove them- and maybe, reuse them.
One option that pops up now and again is a rear entry suit (whose back is like a hatch) that never enters the habitation module. You just back up to the lander, someone opens the back of the suit, and you ease yourself out of the suit and into the vehicle. That way the outside stays outside, as if the lunar surface is a CDC bio-hazard lab.