Should, Shouldn't, Couldn't...What we need to make on Mars...

Dook · 2017-04-23 16:24:51

RobertDyck wrote:

Dook wrote:
The arriving Mars Habs are not perfect? If the tuna can is built with a carbon composite outer shell, an 18" thick hydrogen impregnated fabric layer, then a 6" water sack full of water in flight, then another 6" water sack that will be filled with water on Mars, then regolith on top, would that be enough?
Effective radiation shielding on Mars requires 2.4 metres thick regolith. Converting to US measure, 2.4m = 7' 10.5" while 2.5m = 8' 2.425", so rounding for significant digits we're talking about 8 feet depth. That's a lot of weight. A tuna can will hold a layer or two of sandbags filled with regolith, but not 8 feet. The surface of Mars has half the radiation of ISS, so it's fine for a science mission. But if you want to permanently live there, you need more. A habitat with 8 feet or more of regolith, and a cantilevered roof with an overhang at windows, with some sort of soffit. The 8 feet of regolith would be piled on the roof, including the overhang. So most of the sky would be shaded from the window. It may seem strange, but you don't want direct sunlight shining in through a window most of the time. That sunshine feels good, but includes solar radiation. I have suggested two pane windows, with the outer pane made of tempered glass and the gap between panes filled with mineral oil. Tempered glass is to prevent scratches during dust storms. Mineral oil is how windows of radiation hot cells are made. None of this is how a tuna can is built. I have also argued for an ambient light greenhouse, with argon gas between panes. Time in the greenhouse has to be counted as time in a spacesuit outside. And to restrict radiation exposure to equal limits for a nuclear reactor worker in the US, time outdoors in a spacesuit (or greenhouse) has to be limited to 40 hours per week, where a "week" is defined as 7 Mars solar days. That's a work week, so shouldn't be a problem.
All this is a lot more than a tuna can. A Mars Direct tuna can hab makes a great exploration vehicle, and a great construction shack. However, permanent settlement will require a lot more. A permanent settlement will require tools.

The tuna can doesn't have to hold 8 feet of regolith. How thick is Mars? Enough to shield the crew during night. During day, the tuna can has a 1/4" thick carbon composite shell, an 18" thick fabric, 6" of water, another 6" of water, and a foot or two regolith on top.

They do need a permanent habitat that has 8 feet of regolith shielding that's why I want them to build a greenhouse and partially dig out an area underneath that greenhouse to build a buried habitat.

They could use two ATV's with regolith buckets on the front to build regolith hills inside the area that will become the greenhouse. Assemble the greenhouse, use the zeolite panels to get water, put the water into containers.

Then use the ATV's to dig out an area in the greenhouse. The buckets could have a blade on the back of them and be flipped manually to either move dirt or carry it in the bucket.

They dig down ten feet or so, depending on how much rock they hit, then they place a .5" by 30' circular fiberglass floor panel, then use water and regolith mix to spray mud onto aluminum screens to build up a thick mud wall, maybe 1' thick, all the way around. Dry the mud with solar reflecting panels. All the water used in the mud would evaporate inside your greenhouse and be recaptured.

Once the mud wall is finished they would place an 8" thick 30' across circular fiberglass composite ceiling panel and bury it with the ATV dozers. If the greenhouse was large enough, maybe a dome 100' across, they could build multiple buried circular shelters all connected.

That would provide radiation shielding and a habitat that is inside your greenhouse.

The only tools needed are two battery powered ATV's, a mud sprayer with hopper, water containers, some aluminum screen, and some shovels and buckets.

louis · 2017-04-23 16:32:54

I'm assuming there must be a trade off between your tuna can as a spacecraft (we try to make them as light as possible) and your tuna can as a long term living area (you have to make it strong enough to carry the weight of all that radiation protection).

The alternative, of switching from a lander to a hab (my preferred situation) avoids that trade off. Plus it means you can make your lander a small craft.

Dook wrote:

RobertDyck wrote:
Dook wrote:
The arriving Mars Habs are not perfect? If the tuna can is built with a carbon composite outer shell, an 18" thick hydrogen impregnated fabric layer, then a 6" water sack full of water in flight, then another 6" water sack that will be filled with water on Mars, then regolith on top, would that be enough?
Effective radiation shielding on Mars requires 2.4 metres thick regolith. Converting to US measure, 2.4m = 7' 10.5" while 2.5m = 8' 2.425", so rounding for significant digits we're talking about 8 feet depth. That's a lot of weight. A tuna can will hold a layer or two of sandbags filled with regolith, but not 8 feet. The surface of Mars has half the radiation of ISS, so it's fine for a science mission. But if you want to permanently live there, you need more. A habitat with 8 feet or more of regolith, and a cantilevered roof with an overhang at windows, with some sort of soffit. The 8 feet of regolith would be piled on the roof, including the overhang. So most of the sky would be shaded from the window. It may seem strange, but you don't want direct sunlight shining in through a window most of the time. That sunshine feels good, but includes solar radiation. I have suggested two pane windows, with the outer pane made of tempered glass and the gap between panes filled with mineral oil. Tempered glass is to prevent scratches during dust storms. Mineral oil is how windows of radiation hot cells are made. None of this is how a tuna can is built. I have also argued for an ambient light greenhouse, with argon gas between panes. Time in the greenhouse has to be counted as time in a spacesuit outside. And to restrict radiation exposure to equal limits for a nuclear reactor worker in the US, time outdoors in a spacesuit (or greenhouse) has to be limited to 40 hours per week, where a "week" is defined as 7 Mars solar days. That's a work week, so shouldn't be a problem.
All this is a lot more than a tuna can. A Mars Direct tuna can hab makes a great exploration vehicle, and a great construction shack. However, permanent settlement will require a lot more. A permanent settlement will require tools.
The tuna can doesn't have to hold 8 feet of regolith. How thick is Mars? Enough to shield the crew during night. During day, the tuna can has a 1/4" thick carbon composite shell, an 18" thick fabric, 6" of water, another 6" of water, and a foot or two regolith on top.
They do need a permanent habitat that has 8 feet of regolith shielding that's why I want them to build a greenhouse and partially dig out an area underneath that greenhouse to build a buried habitat.
They could use two ATV's with regolith buckets on the front to build regolith hills inside the area that will become the greenhouse. Assemble the greenhouse, use the zeolite panels to get water, put the water into containers.
Then use the ATV's to dig out an area in the greenhouse. The buckets could have a blade on the back of them and be flipped manually to either move dirt or carry it in the bucket.
They dig down ten feet or so, depending on how much rock they hit, then they place a .5" by 30' circular fiberglass floor panel, then use water and regolith mix to spray mud onto aluminum screens to build up a thick mud wall, maybe 1' thick, all the way around. Dry the mud with solar reflecting panels. All the water used in the mud would evaporate inside your greenhouse and be recaptured.
Once the mud wall is finished they would place an 8" thick 30' across circular fiberglass composite ceiling panel and bury it with the ATV dozers. If the greenhouse was large enough, maybe a dome 100' across, they could build multiple buried circular shelters all connected.
That would provide radiation shielding and a habitat that is inside your greenhouse.

The only tools needed are two battery powered ATV's, a mud sprayer with hopper, water containers, some aluminum screen, and some shovels and buckets.

louis · 2017-04-23 17:19:39

RobertDyck wrote:

They also have a CNC Wood Room, and well equipped Woodworking Room. However, Mars doesn't have trees so I don't think that will be useful on Mars.
I'm thinking many of these tools will have to be sent from Earth. But I'm hoping the heaviest can be made on Mars. Send key components, but fabricate the heaviest parts on Mars.

Whilst growing trees on Mars would probably be a few decades after the first landing growing bamboo should definitely be pursued as an early option. Bamboo grows quickly - some varieties phenomenally quickly (tens of feet in a few weeks) and the plant has many of the qualities of wood meaning it can be used for a wide range of purposes. So wood turning with bamboo would (excuse the pun) be very much to the point.

Oldfart1939 · 2017-04-23 17:46:52

An ATV "Dozer" is usually called a Bobcat. A standard ATV wouldn't be built strongly enough to do any excavation. Where did the sprayer come from? That implies a big compressor and a feed system for solids. Where did we get all the XS water for this project.

I do like the concept of combining the human habitats with the agricultural greenhouses, which would keep water losses to a minimum level. My concept for habs is somewhat different, and would incorporate the large cylindrical fuel tanks of expended vehicles laid on their sides, then rolled into excavated trenches, then covered with regolith for shielding. The spoil from the excavation process would provide the needed regolith such that the depth of excavation doesn't become excessive.

louis · 2017-04-23 17:53:13

You'd need to scrub those tanks out wouldn't you before they could be used by humans?

I am a fan of cut and cover. But why not make Mars bricks and steel supports to provide the "cover" (on top of which you pile regolith)?
A Mars cement or plaster can seal the interior.

Oldfart1939 wrote:

An ATV "Dozer" is usually called a Bobcat. A standard ATV wouldn't be built strongly enough to do any excavation. Where did the sprayer come from? That implies a big compressor and a feed system for solids. Where did we get all the XS water for this project.
I do like the concept of combining the human habitats with the agricultural greenhouses, which would keep water losses to a minimum level. My concept for habs is somewhat different, and would incorporate the large cylindrical fuel tanks of expended vehicles laid on their sides, then rolled into excavated trenches, then covered with regolith for shielding. The spoil from the excavation process would provide the needed regolith such that the depth of excavation doesn't become excessive.

Oldfart1939 · 2017-04-23 18:50:21

Louis-

No scrubbing needed if we use LOX tankage. Ditto if the fuel is Methane. What we need is structure that's capable of supporting the weight of necessary regolith.

louis · 2017-04-23 19:02:13

LOX I can understand but methane?

Oldfart1939 wrote:

Louis-
No scrubbing needed if we use LOX tankage. Ditto if the fuel is Methane. What we need is structure that's capable of supporting the weight of necessary regolith.

RobertDyck · 2017-04-23 19:15:48

No need to scrub LH2 either. However, RP1 is highly refined kerosene, basically highly refined diesel fuel, it would have to be scrubbed. But I don't think anyone is proposing RP1 for any stage to Mars.

Yup, an ATV "Dozer" is a Bobcat. Actually, that's a brand name, the generic term is "loader", they could be "skid steer loader" or "compact track loader". I ran into a salesman for Brandt, a direct competitor for Bobcat; he took exception. Anyway, I agree, we need a loader for Mars.

Habitat integrated with greenhouse? I believe we're all saying that. And we're all arguing for "cut and cover". The only difference is details.

I'm afraid I stuck my foot in one issue. Bruce Mackenzie is the guy who proposed making bricks on Mars. His big idea was Roman arches: barrel arches, groin arches, basic Roman technology. He wanted to cover the bricks in regolith, providing counter pressure to air pressure by ensuring the regolith piled on top would provide more weight than air pressure within the structure. During the Mars Homestead Project I opened my mouth, said I was afraid air pressure would find a weakness in the mortar, and a path through loose soil to the surface. It would leak like a sieve. So Mark Homnick (the other founder of the project) suggested we spray a sealant on the inside surface of the brick. Ok, that works. But that's something else we have to either make or bring from Earth. I see that I wasn't invited to phase 2 - the Plains Settlement, and that phase 2 did not use any brick. Umm...

Dook · 2017-04-23 19:25:16

Oldfart1939 wrote:

An ATV "Dozer" is usually called a Bobcat. A standard ATV wouldn't be built strongly enough to do any excavation. Where did the sprayer come from? That implies a big compressor and a feed system for solids. Where did we get all the XS water for this project.
I do like the concept of combining the human habitats with the agricultural greenhouses, which would keep water losses to a minimum level. My concept for habs is somewhat different, and would incorporate the large cylindrical fuel tanks of expended vehicles laid on their sides, then rolled into excavated trenches, then covered with regolith for shielding. The spoil from the excavation process would provide the needed regolith such that the depth of excavation doesn't become excessive.

An ATV dozer is usually called a bobcat? You can use whatever name you want to use and I can use the name I wish to use. The vehicle I'm describing is an ATV with a bucket/blade, not a bobcat.

An ATV wouldn't be built strongly enough to do any excavation? They have snow plows for ATV's and I have a tow behind blade for my ATV. Using a push blade to move loose regolith would be take some practice, they couldn't attempt to move too much material at a time and would have to be careful not to hit embedded rocks. Having the blade on the rear would be better for digging.

Where did the sprayer come from? Buy one at Home Depot, test it, then either modify it or make one that has the desired modifications.

A sprayer implies a big compressor and a feed system for solids? It's not big, the hopper is probably about 2' x 2'.

Where did we get all the water for this project? The greenhouse will heat up and Mars regolith will outgas some water vapor, we will also use the zeolite panels, shipped water, and the WAVAR on the Mars Hab.

You would use large expended fuel tanks? From what space vehicle? How do you get the tanks to the surface of Mars?

The problem with digging into Mars is rock. Permafrost will melt in time once you expose it but large rock is a show stopper. We can't pick the exact spot we land at.

Oldfart1939 · 2017-04-23 19:49:05

The difference between what a ATV with a blade can move versus what a Bobcat can do is an order of magnitude. I've owned and used REAL equipment on my ranch, and I laugh at what an ATV with a blade or small loader can do by way of comparison. It comes down to the hydraulics and power available to move substantial amounts of regolith, not just push a little around. Just Google up "Bobcat skid steer front loaders." We're talking bucket capacity of nearly a ton per scoop. and that's with a small unit easily capable of being in an early lander. As you've been told elsewhere by kbd512, you really need to educate yourself on engineering realities and stick to facts--no matter how much they are at variance with your preconceptions. Just the amount of energy expended in scooping manure and uneaten hay from a corral takes a LOT of energy and lifting capacity.
For your elucidation:
http://www.bobcat.com/loaders/features

Last edited by Oldfart1939 (2017-04-23 19:50:17)

Dook · 2017-04-23 21:46:44

Oldfart1939 wrote:

The difference between what a ATV with a blade can move versus what a Bobcat can do is an order of magnitude. I've owned and used REAL equipment on my ranch, and I laugh at what an ATV with a blade or small loader can do by way of comparison. It comes down to the hydraulics and power available to move substantial amounts of regolith, not just push a little around. Just Google up "Bobcat skid steer front loaders." We're talking bucket capacity of nearly a ton per scoop. and that's with a small unit easily capable of being in an early lander. As you've been told elsewhere by kbd512, you really need to educate yourself on engineering realities and stick to facts--no matter how much they are at variance with your preconceptions. Just the amount of energy expended in scooping manure and uneaten hay from a corral takes a LOT of energy and lifting capacity.
For your elucidation:
http://www.bobcat.com/loaders/features

A bobcat can do more than an ATV with a blade? It can but, I don't know what bobcats weigh but I think it's about 8,000 lbs, they run on gasoline and oxygen. Where are you going to get the gasoline and oxygen from?

A 114 lb (Mars weight) ATV can run on three batteries and be recharged by connecting to base power. And there will be two of them. And Mars has less gravity so regolith weighs less than half as much as Earth dirt so your bobcat is way overkill and won't work because you can't carry enough oxygen for it. But hey, all that matters is that you have some education in farming in Wyoming, doesn't really matter if it applies to Mars.

One idea is in a hurry, the other is not. One idea means less food taken along, the other means a whole lot of food taken. One idea means no long range rover to go out and get supplies, the other has a long range rover with the two ATV's.

Your constant attitude means you lost the argument a long time ago. It was probably the ridiculous "thousand gallon a day" idea or the sewage treatment plant.

Last edited by Dook (2017-04-23 21:48:06)

SpaceNut · 2017-04-23 22:08:03

ATV with attachments

UTV with Plow

Typical Bobcat dozer

typical bobcat loader

The reason you want mass for the object to push with is due to mars lower gravity....the other is due to reduced traction of the item doing the pushing....

Dook · 2017-04-23 23:24:50

SpaceNut wrote:

ATV with attachments
UTV with Plow
Typical Bobcat dozer
typical bobcat loader
The reason you want mass for the object to push with is due to mars lower gravity....the other is due to reduced traction of the item doing the pushing....

A typical small ATV on the Earth weighs 300 lbs. On Mars it would weigh 114 lbs but with a person in a space suit that adds another 76 lbs probably. So, it's a bit lightweight but the material it's moving is less than half Earth weight too.

To dig the ATV would have to tow the blade behind it. For an ATV to use a front blade to move already loose material or sand, the blade would be manually positioned and locked in place and it would not be able to go lower than the wheels to prevent it from digging in.

One ATV could dig a circular track with a towed blade, the other ATV could follow with a front blade canted to move the loose dirt outward.

RobertDyck · 2017-04-24 02:55:42

For the Mars Homestead Project, the project was to design the first settlement. Since the scope of the project was not to design a spacecraft, I suggested we assume astronauts arrive in Mars Direct habitats. Since the project assumed 12 settlers, that meant 3 habitats. The guys chose to assume a 4th habitat sent without crew to act as backup, and deliver additional equipment. Each Mars Direct habitat includes a rover, one reason is in case the habitat lands significantly far from the intended landing site. But since the 4th would not include crew, we assumed it would carry a Bobcat instead. But again, to avoid promoting brand names and because you guys are posting competing links, I should post a link to the other brand of loader: Brandt / John Deere / Ditch Witch.
Skid Steers
Compact Track Loaders
Mini Skid Steers - stand behind, not ride

Dook · 2017-04-24 03:01:13

RobertDyck wrote:

For the Mars Homestead Project, the project was to design the first settlement. Since the scope of the project was not to design a spacecraft, I suggested we assume astronauts arrive in Mars Direct habitats. Since the project assumed 12 settlers, that meant 3 habitats. The guys chose to assume a 4th habitat sent without crew to act as backup, and deliver additional equipment. Each Mars Direct habitat includes a rover, one reason is in case the habitat lands significantly far from the intended landing site. But since the 4th would not include crew, we assumed it would carry a Bobcat instead. But again, to avoid promoting brand names and because you guys are posting competing links, I should post a link to the other brand of loader: Brandt / John Deere / Ditch Witch.
Skid Steers
Compact Track Loaders
Mini Skid Steers - stand behind, not ride

How was the loader powered? Was it just a normal Earth loader or was it a more lightweight aluminum model?

louis · 2017-04-24 03:04:28

Dook wrote:

SpaceNut wrote:
ATV with attachments
Love the ATV - we need something v. compact like that but obviously pressurised. People should be able to move easily between different parts of the base and they can do that in a pressurised vehicle.
Basically for Mars we need two attachments - the snow plough blade, for moving stones, rocks and small boulders out of the way and the digger (modified to incorporate a microwave radiation device, so as to soften up the soil), to enable us to dig out water ice and ores.
Not sure if you meant to post a video of a toy Bobcat but a larger version of that remote control vehicle would actually be v. useful on Mars (scale it up by 5 and you have something that can do some serious work). Perhaps it would make more sense to have a robot digger which could be controlled from the rover and the rover has the blade (which can be lifted over the chassis when not in use?

UTV with Plow
Typical Bobcat dozer
typical bobcat loader
The reason you want mass for the object to push with is due to mars lower gravity....the other is due to reduced traction of the item doing the pushing....
A typical small ATV on the Earth weighs 300 lbs. On Mars it would weigh 114 lbs but with a person in a space suit that adds another 76 lbs probably. So, it's a bit lightweight but the material it's moving is less than half Earth weight too.
To dig the ATV would have to tow the blade behind it. For an ATV to use a front blade to move already loose material or sand, the blade would be manually positioned and locked in place and it would not be able to go lower than the wheels to prevent it from digging in.
One ATV could dig a circular track with a towed blade, the other ATV could follow with a front blade canted to move the loose dirt outward.

louis · 2017-04-24 03:05:30

Something wrong with the posting?

louis · 2017-04-24 03:07:40

SpaceNut,

You posted a link to a toy Bobcat. Not sure if that was intentional, but I am now thinking it would make sense perhaps to have a scaled up robot Bobcat digger controlled from the rover and that the rover should have a snow plough blade attachment (which can be lifted over the chassis of the rover when not in use).

Last edited by louis (2017-04-24 03:08:20)

RobertDyck · 2017-04-24 03:28:27

Dook wrote:

How was the loader powered? Was it just a normal Earth loader or was it a more lightweight aluminum model?

The links above are normal Earth loaders. What we assumed for Mars was a custom model. For one, it couldn't be powered by a gasoline or diesel engine; Mars doesn't have an oxygen atmosphere. You could argue for a rechargeable electric vehicle, but Robert Zubrin suggested methane / oxygen so vehicles would get their fuel from the same ISPP device that produces propellant for the ERV. Natural gas is mostly methane, so the only real difference is this engine wouldn't have nitrogen from air to dilute oxygen. You could talk to GW Johnson about engine design. The device for Mars would have to be weight reduced; for one Mars has 38% gravity, for another the cost of transport to Mars is so great that expensive weight reductions are more than offset by reducing the cost of transport. However, you don't want to use aluminum for construction equipment, it just won't stand up. You can use titanium alloy. Titanium isn't lighter than steel, but it's substantially stronger so you can use thinner support members to reduce weight. I'll let vehicle engineers work out details.

TV ad: steel vs aluminum

Oldfart1939 · 2017-04-24 08:00:59

The particular "Bobcat" model I selected weighs under 3000 kg, with no effort made to reduce weight. The weight IS important, since that determines the 'tip" load in the bucket.

rbg512: I too, get tired of personal attacks when the data presented doesn't conform to Dook's preconceptions. He really needs to take some time and read through some of the proposals presented in earlier threads. I have better things to do with my time than be redundant in re-presenting earlier proposals. The Bobcat could be adapted to methane/LOX for power as suggested by Robert Zubrin. There's a real learning curve involved when doing any serious Earth (regolith!) moving. There's a reason the equipment is HEAVY. Most rookies using too-small equipment generally tend to burn out clutches, wreck the hydraulics, or damage the transmissions. That cannot be allowed on Mars, as there would be no immediate replacements.

Oldfart1939 · 2017-04-24 08:22:48

A few additional comments re: operation of any type of regolith moving equipment. In my previous post, I commented about the possibility of wrecking the equipment by underestimating the magnitude of the job requirements. It's also not a great idea to combine the essential rover with the secondary task of construction. Blow the hydraulics? Maybe can be repaired if we have a 3-D printer. Tip it over? Not good. Injuries abound in heavy equipment accidents. In 20+ years of part-time ranching, I never tipped over a tractor, but sure did blow a lot of hydraulic lines, and had wheels come off the vehicle due to failure of retaining clips. Rule of thumb: always oversize the equipment to the proposed job at hand. Period. I didn't go to school to learn any of this, other than the school of hard knocks. I learned a lot from neighbors who had done this sort of work their entire lives. If we are talking about burying Habs, then we need to have some serious equipment available to do this job.

Dook · 2017-04-24 10:53:28

Oldfart1939 wrote:

The particular "Bobcat" model I selected weighs under 3000 kg, with no effort made to reduce weight. The weight IS important, since that determines the 'tip" load in the bucket.
rbg512: I too, get tired of personal attacks when the data presented doesn't conform to Dook's preconceptions. He really needs to take some time and read through some of the proposals presented in earlier threads. I have better things to do with my time than be redundant in re-presenting earlier proposals. The Bobcat could be adapted to methane/LOX for power as suggested by Robert Zubrin. There's a real learning curve involved when doing any serious Earth (regolith!) moving. There's a reason the equipment is HEAVY. Most rookies using too-small equipment generally tend to burn out clutches, wreck the hydraulics, or damage the transmissions. That cannot be allowed on Mars, as there would be no immediate replacements.

You get tired of the personal attacks? You are the one who not only started with the personal attacks but have continued them simply because I disagreed with you.

From Oldfart1939:

Your entire rant is filled with assumptions which are demonstrably incorrect. You need to do some better research.
Dook, on the other hand is a total negativist.
you are pushing the boundaries of normal civil discourse here by falsely attributing statements to me that I didn't make.
Your knowledge of how minerals are extracted is underwhelming.
Water processing is another gap in your knowledge base.
There you go again, trying to put words into my mouth.
On one of the other threads you have not read prior to becoming Mr. Know-it-all here
I don't know what part of the universe you live, but certainly have never been on a farm or in an industrial chemical plant as I have.
Please read before commenting.
You flunk Chemistry 101.
Dook, have you taken Physics?
they will NOT give up the adsorbed water without a struggle as Dook assumes
Dook - No. You do NOT know about zeolites

When I get something wrong, you can provide the correct information. If you want to use that as a chance to put me down, I will respond with a put down. I can play that game too.

You think a first settlement needs a sewage treatment plant and a completely ridiculous "thousand gallon a day" water processing ability.

You think you're smarter than Zubrin but you can't improve upon his 30 year old ideas. You guys want to play the "I'm smarter than you are game" but you're not smarter. You have expertise in some areas that the rest of us may or may not have. I have expertise that some of you don't have. All of that should add to the knowledge here but it doesn't when you get your little feelings hurt because someone disagreed with you.

kbd512 · 2017-04-24 11:19:24

A small radio-controlled ATV / dozer with a very low center of gravity, i.e. a machine with most of its weight very close to the ground, could work well, even though it lacks the weight of a larger machine. This is the same mechanical principle that allows a relatively small dog on a leash to drag a much heavier human or sled around.

Let's say we have two tracked machines similar to the Goliath radio-controlled tracked anti-tank mines that the Germans used in WWII. Even though these machines are much lighter than a Bobcat, because the machines have exceptionally low CG, high torque electric motors, and good traction provided by tracks vs wheels, they could still move a respectable amount of regolith because they're so low to the ground. Any higher-CG machine like a Bobcat or an ATV with a rider on it must be much heavier in order to push a given weight of material around.

The remote control could be corded to keep it simple, but I think low-power radio-control will work just fine as long as the electronics are rad-hard. The astronaut could sit or lay on the machine and use a joystick directly connected to the machine if we want to make it ridiculously simple (no micro-electronics except for the Lithium-ion battery discharge controllers), but I think keeping humans away from the earth moving machinery is a prudent way to reduce the potential for difficult-to-treat injuries.

The Husqvarna controllers for their Lithium-ion batteries (not actually their technology, they partnered with some other company whose name escapes me at the moment) are a good example of the battery technology we want. The batteries recharge in half an hour to an hour. The controller maintains full battery output until a cut-off point is reached where it basically shuts off the battery. Obviously the battery packs would not be simple plastic bricks, but I like the idea of having multiple packs that work in multiple tools. The dozers obviously require multiple packs to run, but we need power packs for multiple power tools like blowers (to blow regolith off machinery and out of the garage or storage shed; more like a turbine than a simple fan), bit drivers, and cutting tools.

RobertDyck · 2017-04-24 11:29:22

kbd512 wrote:

A small radio-controlled ATV / dozer with a very low center of gravity, i.e. a machine with most of its weight very close to the ground, could work well, even though it lacks the weight of a larger machine. This is the same mechanical principle that allows a relatively small dog on a leash to drag a much heavier human or sled around.

Ditch Witch brand Mini Skid Steers appear to match your description. However, their tipping load is still lower than their operating weight.

louis · 2017-04-24 12:51:09

This underlnes that a proper Mars analogue environment facility (MAEF) is absolutely essential. This could have Mars temperatures, Mars analogue regolith, Mars light conditions (sol cycle of course) and Mars atmosphere/air pressure. Make it 200 metres by 100 metres.

kbd512 wrote:

A small radio-controlled ATV / dozer with a very low center of gravity, i.e. a machine with most of its weight very close to the ground, could work well, even though it lacks the weight of a larger machine. This is the same mechanical principle that allows a relatively small dog on a leash to drag a much heavier human or sled around.
Let's say we have two tracked machines similar to the Goliath radio-controlled tracked anti-tank mines that the Germans used in WWII. Even though these machines are much lighter than a Bobcat, because the machines have exceptionally low CG, high torque electric motors, and good traction provided by tracks vs wheels, they could still move a respectable amount of regolith because they're so low to the ground. Any higher-CG machine like a Bobcat or an ATV with a rider on it must be much heavier in order to push a given weight of material around.
The remote control could be corded to keep it simple, but I think low-power radio-control will work just fine as long as the electronics are rad-hard. The astronaut could sit or lay on the machine and use a joystick directly connected to the machine if we want to make it ridiculously simple (no micro-electronics except for the Lithium-ion battery discharge controllers), but I think keeping humans away from the earth moving machinery is a prudent way to reduce the potential for difficult-to-treat injuries.
The Husqvarna controllers for their Lithium-ion batteries (not actually their technology, they partnered with some other company whose name escapes me at the moment) are a good example of the battery technology we want. The batteries recharge in half an hour to an hour. The controller maintains full battery output until a cut-off point is reached where it basically shuts off the battery. Obviously the battery packs would not be simple plastic bricks, but I like the idea of having multiple packs that work in multiple tools. The dozers obviously require multiple packs to run, but we need power packs for multiple power tools like blowers (to blow regolith off machinery and out of the garage or storage shed; more like a turbine than a simple fan), bit drivers, and cutting tools.

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#26 2017-04-23 16:24:51

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