back to article DARPA tasks Northrop Grumman with drafting lunar train blueprints

All aboard the space train – DARPA has commissioned defense contractor Northrop Grumman to figure out what would be necessary for a railroad network on the Moon. Northrop Grumman announced that DARPA selected it yesterday, describing the defense agency's vision for a Moon train as one that could transport humans, supplies, and …

  1. Pascal Monett Silver badge
    Holmes

    "figure out what would be necessary for a railroad network on the Moon"

    Step 1 : eliminate the incredibly abrasive influence of Moon regolith on railroad tracks.

    We'll continue when you've solved that.

    1. DS999 Silver badge

      Re: "figure out what would be necessary for a railroad network on the Moon"

      The expansion/contraction between the two weeks of night and two weeks of day would be massive, that may be an even bigger issue than the abrasion (since it is safe to assume the railroad would not be particularly busy anytime soon after it is built)

      1. HandleBaz

        Re: "figure out what would be necessary for a railroad network on the Moon"

        You're all assuming this would run on the surface, which is a mistake, becasue of Solar storms.

        Nasa already started thinking about this in the 80s, see the frankly wild proposal for a nuclear powered TBM in this fascinating document about lunar materials, that creates titanium-glass coated tunnels for habitats and or infrastructure.

        https://www.lpi.usra.edu/publications/books/lunar_bases/LSBchapter07.pdf

    2. Dave 126 Silver badge

      Re: "figure out what would be necessary for a railroad network on the Moon"

      > We'll continue when you've solved that.

      A brush.

      1. Anonymous Coward
        Anonymous Coward

        Re: "figure out what would be necessary for a railroad network on the Moon"

        > A brush.

        Take a broom, it'll be easier. You will only need to take the one, when the head wears out you can just replace it, same with the handle.

        1. Hurn

          Re: "figure out what would be necessary for a railroad network on the Moon"

          Broom of Theseus?

        2. Spherical Cow Silver badge

          Re: "figure out what would be necessary for a railroad network on the Moon"

          Trigger's Broom

          https://youtu.be/56yN2zHtofM

          1. jake Silver badge

            Re: "figure out what would be necessary for a railroad network on the Moon"

            Arkwright's Brush

            https://www.youtube.com/watch?t=29&v=8XOKopHtoJQ

      2. DS999 Silver badge

        Re: "figure out what would be necessary for a railroad network on the Moon"

        Then the dust will stick to the brushes.

        Moon dust is highly charged - positive during the day when solar radiation knocks out its electrons, and negative at night due to electron bombardment from the solar wind. A small charge on the track might be enough to keep the dust off it. Just have to change the charge depending on whether it is day or night, and I suppose not run any trains during sunrise/sunset when the charge is changing?

    3. jake Silver badge

      Re: "figure out what would be necessary for a railroad network on the Moon"

      Wheels similar to those of the Rovers of old, but more of them. A "road train", with (ceramic?) bearings in the axle housings behind a seal or seals to maintain the housings at a positive pressure, thus keeping the dust out It wouldn't take very much pressure at all, and use whatever gas is (relatively) plentiful. Removes the need for any kind of rail system, and allows easy re-routing as necessary. Running overhead wires for power is a no brainer; pantographs and the like are known tech.

      1. 42656e4d203239 Silver badge
        Meh

        Re: "figure out what would be necessary for a railroad network on the Moon"

        >>Running overhead wires for power is a no brainer; pantographs and the like are known tech.

        All the moving parts (rather more than you may initially think) required to make overhead lines work for terrestrial trains will need modifying for the incredibly abrasive environment.

        Gravity plays a large part in making overhead traction power supplies work here on Sol 3.... slight problem with that on the mun IIRC in that there is much less of it around to keep things pointing generally downwards. Oh and the support gantries will need fixing as well... which is a whole new field of pain.

        I would suggest overhead wires for power, on the mun, is far from being a "no brainer".

        FLOAT looks like a much more promising system - Maglev, too, is proven tech these days, has fewer moving parts required for traction plus it shouldn't be too hard to keep the induction coils cool (at least 14 days out of 28; granted the rest of the time it might be more tricky)

        1. Dave 126 Silver badge

          Re: "figure out what would be necessary for a railroad network on the Moon"

          The vacuum would help reduce heat transfer. This is an area of interest for mooted projects for transferring electrical power by superconducting cable from a fission power plant to a moon base.

          1. 42656e4d203239 Silver badge

            Re: "figure out what would be necessary for a railroad network on the Moon"

            Yeh - the Vacuum is a mixed blessing. In the dark times it helps by there not being convection to worry about heating up the superconductor, however it means that during the daytime any of the structure hit by unattenuated sunlight has to radiate that energy back to space or get hotter... which isn't good news for many reasons.

        2. jake Silver badge

          Re: "figure out what would be necessary for a railroad network on the Moon"

          Trolley poles don't have that many moving parts. Make the wear points replaceable (as they do down here on Earth), and put a boot around necessary places with a charged brush to repel the abrasive particles "stuck" to the wire. I'm pretty sure that human ingenuity can make something like this work.

          Also, schedule trips for times when activity isn't kicking up a lot of dust. Unlike here on Earth, there is no atmosphere to hold particles for hours or days, they should settle out in seconds.

      2. rg287 Silver badge

        Re: "figure out what would be necessary for a railroad network on the Moon"

        Running overhead wires for power is a no brainer; pantographs and the like are known tech.

        For rail though. Where you have a highly consistent distance between wire and rail, and the steel wheels don't compress or bounce.

        Sweden have trialled overhead lines for HGVs, and they do work - ishly. But because trucks have bouncy pneumatic tyres they have to keep the line and pantograph at much higher tensions. This leads to more wear and a higher likelihood of breakage. Or dust clogging the joints on the pan.

        On the Moon.. with a moderately rough surface (unless it were groomed and paved smooth, which is also a topic of research), it's highly likely that downed wires would be a common occurrence when a vehicle hits a rut at the wrong angle and stretches the OHLE a bit too hard. In which case your stranded vehicles would need battery-powered life support that can last until rescue arrives. Or a battery backup good for at least 50% of the journey (to reach the destination or to get home). At which point you're carrying a battery anyway...

        Overcoming the rail abrasion issues seems easier in the long-run (although self-contained BEVs are inevitable in the early days, just as our railways were built using horse and cart), and also lowers the energy requirements of the system, since steel-on-steel uses an order of magnitude less energy than flexible tyres rolling over arbitrary surfaces. Whilst moon dust is highly abrasive, we have to remember that gravity is 16% of Earth's, lowering the pressure and abrasion on the rail. The bigger problem with rails on the moon is going to be thermal expansion.

        1. jake Silver badge

          Re: "figure out what would be necessary for a railroad network on the Moon"

          San Francisco has long used Electric Trolley Buses with standard rubber tires and electric motors powered by overhead wires. It is actually less trouble than the tracked Muni trains.

          https://www.sfmta.com/getting-around/muni/munis-electric-trolley-buses

          They actually use trolley poles, I shouldn't have said "pantographs and the like are known tech", it gave the wrong idea of what I meant.

          Yes, the SF version runs a battery pack so they can go "off wire" for a bit to get around obstacles.

      3. DS999 Silver badge

        Overhead wires?

        That's a lot of infrastructure to build. Even running "tracks" might be pointless once you pinpoint a safe route around craters, boulders etc. and just follow that same route every time. Just rover style wheels that drive on the surface.

        As for power the Moon is ideal for solar, especially if you mostly only travel during the "day" but it could even be made to work during the night if it had to. If the "trains" have detachable battery trailers then you could have waypoints with small solar farms every once in a while that charge up one or more trailers. Your train arrives and your battery trailer(s) automatically detach themselves and drive over to plug into the solar array (even if it is dark the sun will come out eventually) and one or more charged up trailers automatically drives over and attaches, then the train continues on its journey.

        If you don't really care how fast the train goes, it could probably drive itself on solar. Might need some lightweight solar trailers that spread a fairly large array of panels if the "train" is hauling something heavy, and it would only move two weeks out of the month, and maybe it only travels at 1 kph, but it would work. I guess it depends on why someone thinks we need a "railroad" on the Moon. What exactly are we going to be hauling, and over how long of a distance? And why aren't we landing/launching or processing from wherever this stuff is going/coming from, instead of hauling it large distances across the Moon?

    4. Anonymous Coward
      Anonymous Coward

      Re: "figure out what would be necessary for a railroad network on the Moon"

      > Step 1 : eliminate the incredibly abrasive influence of Moon regolith on railroad tracks.

      > We'll continue when you've solved that.

      Giant mirror in space, focus the sunlight and just(!) glass a path from A to B. Fix any crazing due to day/night heating/cooling stresses with a quick pass to spruce it up at dawn.

      Make mirror from thin film across flimsy framework, assembled (inflated) in orbit: cheap and easily replicated, light weight to be shipped up in a multipack. We are supposed to have a staging station in Lunar orbit, so just chuck another one out the door from there as and when.

    5. Locomotion69 Bronze badge

      Re: "figure out what would be necessary for a railroad network on the Moon"

      You need the Moon equivalent of Network Rail first before you will get anything done.

      1. Anonymous Coward
        Anonymous Coward

        Re: "figure out what would be necessary for a railroad network on the Moon"

        I would argue that Network Rail is the very last thing we need...

    6. Spherical Cow Silver badge

      Re: "figure out what would be necessary for a railroad network on the Moon"

      "Step 1 : eliminate the incredibly abrasive influence of Moon regolith on railroad tracks.

      We'll continue when you've solved that."

      Tunnels. Bore a tunnel and sweep it clean, it will stay clean so long as you don't let in Charlie Brown's friend Pig-Pen.

  2. Neil Barnes Silver badge
    Alien

    silicate-rich particles are sharp enough to destroy

    Remind me: wasn't there some research recently, in which it was attempted to grow earth seeds in lunar regolith? I have a vague idea that it was too sharp or spiky to provide a secure mechanical support for the growing seedlings, but I could be misremembering.

    1. TVU

      Re: silicate-rich particles are sharp enough to destroy

      Yes, it was thale cress and the plants seemed stressed at growing in lunar regolith material. Surprisingly, they didn't test any actual food crops and l think that was a mistake. Link below:

      https://www.nasa.gov/humans-in-space/scientists-grow-plants-in-lunar-soil/

      1. jake Silver badge

        Re: silicate-rich particles are sharp enough to destroy

        Food crops? For non-ideal conditions? Nah ... Food crops are bred for a cushy environment.

      2. Neil Barnes Silver badge

        Re: silicate-rich particles are sharp enough to destroy

        Thanks!

    2. jake Silver badge

      Re: silicate-rich particles are sharp enough to destroy

      Given that most seeds much prefer river-run (or otherwise weathered) rock as a growth medium, it wouldn't surprise me. Trying to force the tender tip of a root through what is essentially broken glass would undoubtedly not be ideal.

      1. Dave 126 Silver badge

        Re: silicate-rich particles are sharp enough to destroy

        Terrestrial plants form relationships with the soil fungi they have co-evolved with... The fungi have an impressive chemical toolkit for breaking down inorganic substrates and accessing nutrients. Consider how fine the mycelia are compared to even the thinnest of plant roots; their surface area is immense.

        In return the plants supply sugars to the fungi. Usually. Some plants are parasitic, just as some fungi are.

        1. Neil Barnes Silver badge

          Re: silicate-rich particles are sharp enough to destroy

          Vaguely remembering now, I recall when I read the article wondering whether the results would have been happier had more of a terrestrial biome been included in the lunar regolith, rather than just using the regolith as a plant support.

          (Makes me wonder about The Martian's potatoes, too...)

          1. Wellyboot Silver badge

            Re: silicate-rich particles are sharp enough to destroy

            I'm guessing that as the The Martian's spuds were growing in the astro-poop there's no need for fungi*, sterile regolith mixed in being mostly to provide a bulked up growing medium & drainage.

            Though I'd also hazard that while they might well grow ok they'd not react well to having sharp edges ground into their roots if walked over.

            * Do we have any bio-stuff experts with a paragraph to share lurking here?

      2. TVU

        Re: silicate-rich particles are sharp enough to destroy

        It was also surprising to me that those NASA scientists did not try out growing the plants in a mixture of the lunar regolith material with sterilised human liquid and solid wasted as featured in The Martian (book and film). That would probably have made for a noticeably better plant compost.

  3. alain williams Silver badge

    So what will be the excuses for late trains ?

    Moon trees do not exist, so no "leaves on the line" ...

    "Wrong type of regolith" maybe ?

    1. jake Silver badge

      Re: So what will be the excuses for late trains ?

      "Moon trees do not exist"

      Sure they do.

      https://en.wikipedia.org/wiki/Moon_tree

      1. Anonymous Coward
        Anonymous Coward

        Re: So what will be the excuses for late trains ?

        Yeah - gonna take more than the Beast From The East to blow leaves from those onto the Lunar Rail.

        Although, with Global Warming and everything we've learnt from Oz and Doolittle you might be on to something...

        1. FirstTangoInParis Silver badge

          Re: So what will be the excuses for late trains ?

          I do hope someone is developing the Moon Rail Replacement Bus too.

          1. John Brown (no body) Silver badge

            Re: So what will be the excuses for late trains ?

            Just make sure not to drive into the Sea of Thirst!

  4. Anonymous Coward
    Anonymous Coward

    Monorails look high tech and cool... time for a lunar monorail i think...

    https://en.wikipedia.org/wiki/Gyro_monorail

    Just needs some chaps in space suits editing into the photos...

  5. Dave 126 Silver badge

    Starship did have a successful launch...

    ... just not a successful re-entry. It achieved orbital velocity, and the only reason it didn't actually orbit was because it was never intended to.

    The engineers that gave us Falcon 9, a reusable rocket that has met its stated goal of making spaceflight seem as boring as civil aviation, appear to know what they are doing.

    1. Spherical Cow Silver badge

      Re: Starship did have a successful launch...

      "...with both the craft and its Super Heavy booster breaking apart before the planned end of the mission."

      To be fair, the booster did return to the surface intact... it just couldn't slow down (and thereafter ceased to be intact).

  6. Anonymous Coward
    Anonymous Coward

    Halfway there

    I propose making use of existing infrastructure with a proven track record by extending the California(-Lunar) High Speed Rail system to the moon.

    1. Fruit and Nutcase Silver badge

      Re: Halfway there

      What about Musk's own Hyperloop.

      Now all that is needed is a Fat Controller

      1. John Brown (no body) Silver badge

        Re: Halfway there

        Would it matter if he's orange? I have someone in mind that would do a great job, the best job, a beautiful job!

      2. Bebu
        Windows

        Re: Halfway there

        《What about Musk's own Hyperloop.》The Boring Company came to my mind too.

        《Now all that is needed is a Fat Controller》

        His Muskiness is showing signs of middle aged spread tending to decidedly porky so position already filled. (He obviously now needs a different kind of special-K. ;) Obviously wouldn't require any retraining for role.

        ----

        I imagine cutting open trenches and laying prefabricated tunnel sections in the trenches and backfilling the trenches might be a practical approach.

        You get thermal stability and the tunnel could be be dust (regolith) free (a very slight gas pressure could keep the dust from leaking in through small imperfections.)

        Obviously such a tunnel as on earth would carry more than rail traffic (comms, power, water, effluent [for recycling], air etc.)

        I imagine some sort of lunar cement/concrete could be used to make the tunnel sections.

        Not sure an actual rail is required - in a tunnel a trolley bus type vehicle with solid tyres might be adequate.

        In a tunnel you could even use a canal if you were producing and transporting enough water and kept it just above 0°C so the vapour press is low (600-800Pa.) Lunar barges. ;)

        -----

        I always imagined a trebuchet style devices flinging stuff over the moon's surface - the 1/3g gravity and reduced curvature would give you a fair range and the lack of an atmosphere should mean greater precision and accuracy but with no parachutes which is ok for robust payloads but a bit hard on passengers. ;)

        -----

        Moving skyhooks might be another option. A fairly massive satellite in a low circumlunar orbit trailng a cable reaching to near the surface would rapidly pass over the lunar terrain(sic) but could be contrived to pick up cargo in much the same way moving railway trains used to pick up mail bags.

        ----

        Ask a silly question I guess.

    2. jake Silver badge

      Re: Halfway there

      If they emulate Caifornia's HSR boondoggle, it'll be over 10 times over budget, and they won't even have the right-of-way nailed down for the first (and least needed) portion of the track a decade and a half after construction is authorized to start. Eventually, they will open the first 171 miles of the track over a quarter century after it was authorized (if they are lucky), at a cost of at least 40 billion dollars, and absolutely nobody will use it.

      1. Red Ted
        FAIL

        Re: Halfway there

        171 miles of HSR for $40 billion?

        That's only $234 million per mile. We've managed to make ours cost about $500 million per mile! Costings from this article.

  7. david 12 Silver badge

    Boots on the ground

    Around here, they go into excitement mode when they get any boots on the ground in the rail reservations. Used to be hundreds of people employed in the rail yards, now they stop the trains and send in the security guards.

  8. Dwarf

    I can't wait

    Imagine the fun, you get all the way to the moon and then find out that your train was cancelled and that the next one is in a week, or the the unions are on strike again.

    Probably not so many problems with jumpers on the line though as there are no clothing stores there yet.

  9. Snowy Silver badge
    Joke

    Space Gravy

    In space no one can hear you slurping on the gravy train.

  10. Justin Clift

    > The lunar rail project is part of DARPA's 10-Year Lunar Architecture (LunA-10) project that aims to develop [...] interoperable standards ...

    It'll be using metric like the rest of the space community then yeah? :)

    1. jake Silver badge

      What, 4 ft 8.5 in isn't good enough for you?

      1. Dave 126 Silver badge

        That's ambiguous because US military contractors have been known to do this:

        " The year is now 1951: My first engineering job is at Boeing. I’m designing parts for their new B-52A bomber. I use my own drafting instruments as I work at a huge drawing board. But the company provides me with a special ruler. .... Its inches are divided into tenths. And each tenth is subdivided into tiny slices, two one-hundredths of an inch wide. You see, Boeing conceived the airplane itself in one-inch sections. The B-52’s body was – is – one thousand, nine hundred, and twelve inches long.

        " Boeing had created its own decimal system within the company. Just think how much labor they cut when we didn’t have to keep multiplying and dividing by 12! How much more time did we save when we didn’t have fractions like three-eighths of an inch? ... "

        https://engines.egr.uh.edu/episode/3292

  11. chuckufarley Silver badge

    Randall Munroe Strikes Again!

    https://xkcd.com/2909/

  12. rg287 Silver badge

    Railways? Nasty Commie idea.

    The idea of the United States building a railway on the Moon is laughable given that they're apparently incapable of building a railway in the, err, United States.

    Now, if they'd asked for China to tender... there's a country that knows how to get stuff built (if you don't mind a bit of slave labour).

    1. Anonymous Coward
      Anonymous Coward

      Re: Railways? Nasty Commie idea.

      Given how many Chinese were used to build the railroads, back in the days when US folks were glad to have the trains, that idea has a sound historical basis.

      1. Dave 126 Silver badge

        Re: Railways? Nasty Commie idea.

        I was going to suggest the Japanese. Given their track record (oh dear) of building Mag-lev railways they at first glance appear to have more relevant experience than a defense contractor such as Northrup Grumman... but then I thought, what's the difference between a Mag-lev railway and a rail gun *really*?

        1. rg287 Silver badge
          Mushroom

          Re: Railways? Nasty Commie idea.

          but then I thought, what's the difference between a Mag-lev railway and a rail gun *really*?

          "Terminal ballistics" isn't a chapter I would want in my "Lunar railway operations handbook", but I suppose that's just an implementation detail!

          1. Dave 126 Silver badge

            Re: Railways? Nasty Commie idea.

            It isn't the terminal ballistics that scare me. It's the lithobraking.

        2. that one in the corner Silver badge

          Re: Railways? Nasty Commie idea.

          > what's the difference between a Mag-lev railway and a rail gun *really*?

          Not wanting to be pedantic[1] apparently[2] you are thinking of a "coilgun", as a "railgun" has the projectile as part of the circuit, meaning it is in contact with the rails during the entire acceleration phase. And has potential (ho ho) for lovely sparks and plasma, so pretty.

          [1] oh, who am I kidding?

          [2] personally, I reckon they changed the names on us, 'cos I've been using "railgun" instead of "coilgun" since the 1970's! Anyway, that first link is to a PDF on a dot-mil site, just to reassure you that I'm not just relying on Wikipedia (the next two links); plus the PDF also discusses cool stuff like giant lasers - sadly, without sharks.

  13. Julz

    Road

    Trains aren't new. This one might need a few tweaks though...

    https://www.thedrive.com/news/33645/the-incredible-story-of-the-us-armys-earth-shaking-off-road-land-trains

    1. John Brown (no body) Silver badge

      Re: Road

      Thanks, that was a good read/watch :-)

      I wonder if Patrick Tilley new about that when he wrote The Amtrak Wars?

  14. Dave 126 Silver badge

    Rail or road

    There is a concept to use mirrors and sunlight to sinter loose regolith into roads and other structures.

    A slight tangent, I know, but may be of interest.

    https://interestingengineering.com/innovation/sustainable-building-lunar-roads-melting-regolith

    1. Anonymous Coward
      Anonymous Coward

      Re: Rail or road

      I suggested the same idea a few hours earlier (only with fewer actual citations, so you win) - but didn't get a convo going.

      Guess it is just not - sinteresting.

  15. Anonymous Coward
    Anonymous Coward

    How can I get in on the scam?

    another money pit to drain tax payer money. Fantastic.

    how do I get in on it?

    might as well, as they are going to take it from us anyways.....

    1. Fruit and Nutcase Silver badge
      Trollface

      Re: How can I get in on the scam?

      The dusty regolith would mean the need for a lot of protective coverings/equipment - just ask for advice from those who made an absolute fortune in the UK Covid PPE procurements.

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