Two Scifi Lunar Miner Questions

[Spacescifi]

Premise: Assume excellent lightweight scifi radiation protection is a given. Also assume the moon is a mining base.

Dealing With Low Gravity: Since moon gravity is low, would it be reasonable for miners to wear heavy enough metallic or otherwise heavy suits even inside crew cabins just so they can be ALMOST as heavy as they would be on Earth? I dunno...make the suit with heavy lead plating and other dense heavy materials?

Color Of Moon Concrete: Provided lunar ice is used to make lunar concrete, what color would it be? White? Or gray still?

Are not all concretes naturally a lighter color than the original stuff it came from usually?

 

Thank you.

[RealKerbal3x]

4 minutes ago, Spacescifi said:

Dealing With Low Gravity: Since moon gravity is low, would it be reasonable for miners to wear heavy enough metallic or otherwise heavy suits even inside crew cabins just so they can be ALMOST as heavy as they would be on Earth? I dunno...make the suit with heavy lead plating and other dense heavy materials?

That's just inefficient. On low-g worlds like asteroids (where most offworld mining is likely to take place), it'd be better to just build a centrifuge than make everyone wear ballast.

7 minutes ago, Spacescifi said:

Color Of Moon Concrete: Provided lunar ice is used to make lunar concrete, what color would it be? White? Or gray still?

Are not all concretes naturally a lighter color than the original stuff it came from usually?

I only know as much about concrete as a cursory google search can tell me but it looks like the colour of concrete is at least loosely dependent on the colour of the rock it's made from. So lunar concrete might be a little more grey than Earth concrete.

Lunar water wouldn't affect the colour unless it hadn't been processed and filtered before use, which I doubt.

[Scotius]

Lunar regolith is about as dark as asphalt. Why does it matter anyway? Inside of the building can be painted or covered in siding colored anything you want. Camouflage for the outside? Just shovel some unprocessed regolith on top of it and you're good to go.

[YNM]

2 hours ago, Spacescifi said:

would it be reasonable for miners to wear heavy enough metallic or otherwise heavy suits even inside crew cabins just so they can be ALMOST as heavy as they would be on Earth?

Assuming labour is involved - be it heavy labour or "smart" labour - I'm sure that they'll have breaks and off-work time, where they'd spend their time in the habitation module or something. We can make those to have artificial gravity instead. If anything, for heavy labour it'd be better to leave the workers with less mass (and therefore less weight) on.

2 hours ago, Spacescifi said:

Color Of Moon Concrete: Provided lunar ice is used to make lunar concrete, what color would it be? White? Or gray still?

Depends on the binder used.

If anything, the real question is on the size of the aggregate used. The reason why we add gravel (coarse aggregates) and don't make concrete out of sand (fine aggregates) and hydraulic binder cement only is because they'd shrink when setting in large proportions, also it'd heat up much more due to more binder used, and in general it's more expensive. Now we do have non-shrink grouts which are specially engineered concrete (ok, maybe mortar) with only binder and fine aggregate, and they don't shrink, but it's much more expensive. Unless a different process is used then the fine regolith alone might prove too fine for normal concrete as is made on Earth, you'd have to find the coarser aggregates as well.

Edited January 5, 2021 by YNM

[paul_c]

I think that's basically what they did on the Apollo Lunar missions - the spacesuits were unwieldy on Earth, but once on the moon their extra mass/bulk was manageable.

The main problem would be the "cost per kg" to the moon is so high, there is a massive incentive to lighten everything anyway. The Rover was only about 200kgs?

[K^2]

1 hour ago, Spacescifi said:

Dealing With Low Gravity: Since moon gravity is low, would it be reasonable for miners to wear heavy enough metallic or otherwise heavy suits even inside crew cabins just so they can be ALMOST as heavy as they would be on Earth? I dunno...make the suit with heavy lead plating and other dense heavy materials?

To get the same weight as on Earth, you'd need to make the suits about five times as heavy as the person wearing them. That leads to problems. First of all, you now have six times the inertia. Need to start moving fast? Well, you now have to get something six time as heavy moving while still having only your normal strength and at most as much traction as you'd have on Earth, since that's proportional to weight. Worse, if you managed to get yourself to a good jogging speed, good luck stopping. And then there's vertical movement. Even with the increased inertia, you could probably get to almost as much of a jump speed. So you'd be able to jump 5-6 meters high and then come crashing down with all that weight. In summary, it's all just accidents waiting to happen, potentially in airless environment where a tear would be a very bad thing indeed.

And the benefits? Questionable at best. Yes, one of the problems with low gravity worlds is muscular degeneration, but unlike microgravity, you should be able to keep yourself in decent form so long as you exercise. We don't have hard data on that, but it doesn't sound like you'll need to carry a half-ton suit to keep you in decent shape. Though, wrist and ankle weights, similar to these used for exercising on Earth, might be helpful.

In contrast, you aren't solving the biggest problem, which is the weakening of cardiovascular system. And that's likely to be the biggest problem for prolonged stay on a low gravity world. After all, if you can't walk for a few months after coming back home, that's something you can deal with. If your heart gives out on re-entry, well, that's really bad. And adding weights to your suit isn't helping with that a whole lot. Physical exercise, in general, helps, but we don't know how long we can extend the duration this way and what the effects of spending, say, several years on the Moon would be.

Artificial gravity is the only sensible solution. I don't know if building centrifuge habs on the Moon is practical, though. It might be a lot easier to simply keep all the habs in low lunar orbit and simply ferry workers back and forward. Lack of atmosphere on the Moon and comparatively low orbital velocity means that you can use magrails very efficiently to send cargo and passengers to and from orbit. At least, near the equator. Yes, a lot of the mining operations are likely to be near poles instead, but all of the launch infrastructure is going to be on the equator, so you're probably looking at some form of rail transit between these for any serious industry. So even for operations at poles, I'm not sure if centrifugal hubs are a way to go, or if you want to just brings workers back and forward by rail. If you have workers downside in shifts of a few days at a time, then a few hours on the train aren't a big deal, and so long as they're spending time in between in near-Earth gravity on the station, then low gravity at the work location isn't a big deal.

[Spacescifi]

3 hours ago, K^2 said:

To get the same weight as on Earth, you'd need to make the suits about five times as heavy as the person wearing them. That leads to problems. First of all, you now have six times the inertia. Need to start moving fast? Well, you now have to get something six time as heavy moving while still having only your normal strength and at most as much traction as you'd have on Earth, since that's proportional to weight. Worse, if you managed to get yourself to a good jogging speed, good luck stopping. And then there's vertical movement. Even with the increased inertia, you could probably get to almost as much of a jump speed. So you'd be able to jump 5-6 meters high and then come crashing down with all that weight. In summary, it's all just accidents waiting to happen, potentially in airless environment where a tear would be a very bad thing indeed.

And the benefits? Questionable at best. Yes, one of the problems with low gravity worlds is muscular degeneration, but unlike microgravity, you should be able to keep yourself in decent form so long as you exercise. We don't have hard data on that, but it doesn't sound like you'll need to carry a half-ton suit to keep you in decent shape. Though, wrist and ankle weights, similar to these used for exercising on Earth, might be helpful.

In contrast, you aren't solving the biggest problem, which is the weakening of cardiovascular system. And that's likely to be the biggest problem for prolonged stay on a low gravity world. After all, if you can't walk for a few months after coming back home, that's something you can deal with. If your heart gives out on re-entry, well, that's really bad. And adding weights to your suit isn't helping with that a whole lot. Physical exercise, in general, helps, but we don't know how long we can extend the duration this way and what the effects of spending, say, several years on the Moon would be.

Artificial gravity is the only sensible solution. I don't know if building centrifuge habs on the Moon is practical, though. It might be a lot easier to simply keep all the habs in low lunar orbit and simply ferry workers back and forward. Lack of atmosphere on the Moon and comparatively low orbital velocity means that you can use magrails very efficiently to send cargo and passengers to and from orbit. At least, near the equator. Yes, a lot of the mining operations are likely to be near poles instead, but all of the launch infrastructure is going to be on the equator, so you're probably looking at some form of rail transit between these for any serious industry. So even for operations at poles, I'm not sure if centrifugal hubs are a way to go, or if you want to just brings workers back and forward by rail. If you have workers downside in shifts of a few days at a time, then a few hours on the train aren't a big deal, and so long as they're spending time in between in near-Earth gravity on the station, then low gravity at the work location isn't a big deal.

 

Thanks. I was unaware of heart problems. My prior concern was eyesight even though I did not state it.

In LEO astronauts lose some visual sharpnesss over time, and the damage STAYS even when they go back to Earth.

I want my space miners to have good enough tech to go mine in space,  come back to homeworld, and be just like they were before they left. No worse for wear.

I thought about going the fictional grav boot root (by increasing the gravity force attraction of whatever it touches), but I thought it good to see if there were any good IRL options first.

Seems grav-boots are the most optimal to justify a large miner presence.

I reckon even working 8 hours a day in low g is probably bad for the eyes, and likely bad for the heart too.

Given all these issues, IRL we would only send people to fix broken automated machines.

Automated machines would work alone without us...until they break.

3 hours ago, Scotius said:

Lunar regolith is about as dark as asphalt. Why does it matter anyway? Inside of the building can be painted or covered in siding colored anything you want. Camouflage for the outside? Just shovel some unprocessed regolith on top of it and you're good to go.

 

It matters because I want to get the color right when I write it!

Although in my work it's an alien moon that is pink in color.

So the concrete will probably be very pale pink.

Not likely to be red.

Edited January 5, 2021 by Spacescifi

[YNM]

8 minutes ago, Spacescifi said:

It matters because I want to get the color right when I write it!

Have you ever seen concrete just released from it's formwork ? They're roughly the same colour as the binder used. The same happens with asphalt concrete (yes, they're also a form of concrete - binder with aggregates), you don't see the (sometimes) relatively paler aggregates, you see the black colour of the bitumen/tar used (if anything, if your aggregate stops being covered with black asphalt, they'll soon break free from the road surface).

[Scotius]

It had to be done   #sorrynotsorry!

[kerbiloid]

Apollo suits got camouflaged without any efforts from the crew just after a short walk.

Citrus-colored reflective jackets put on suits is that what they need. LIke the road workers.

Edited January 6, 2021 by kerbiloid

[Scotius]

Or harnesses with blinking lights. They will work well in shaded areas and during the night.

[K^2]

16 minutes ago, Scotius said:

Or harnesses with blinking lights. They will work well in shaded areas and during the night.

We'll just ask PC case modders to take a pass. They'll set them up with some sweet RGB lighting and liquid cooling. Wins all around.

[Spacescifi]

2 hours ago, K^2 said:

We'll just ask PC case modders to take a pass. They'll set them up with some sweet RGB lighting and liquid cooling. Wins all around.

It is really interesting that the greater part of scifi must be fiction to even justify a large  presence of life where it is not supposed to live.

It's not even 50% science, 50% fiction. Not even that amount would jusfify a large amount of folks risking their lives with a lower quality of life than they were born with.

I suppose the ratio would need to be more like 10% science, 90% fiction, since if space is not made relatively safe, no large amount of folks will go.

[YNM]

We actually have gone quite a bit from there, and these days you get a thing to buzz on the rear of your head if you're in proximity of a machine in operation, there are also variants that alerts the machine operator. Shouldn't be "too difficult" (well, would need more hardware and more testing) for the proximity software to tell if you're going to hit a worker, and stop the machine before that ? (although I know there are cases where this would be more dangerous, and would be somewhat inconvenient.)

Edited January 6, 2021 by YNM