Long Term Mars Habitat

Dook · 2016-09-28 14:45:38

I still have a lot of work to do on this idea, have to try and figure out how many launches it would take to get all of these components to Mars, but I thought I would post what I have so far.

Long Term Buried Mars Habitat

A buried two story, 20' x 20', square habitat with 7' high ceilings buried beneath (needs to be 2.5 meters) of Martian regolith. The upper level of the buried habitat is the sleeping level with four sleeping rooms, a common area, a microwave, a water tank, and a central bathroom/toilet. The bottom level of the buried habitat is the greenhouse where fruit trees are grown in large plastic tubs and vegetables are grown in long rectangular tubs.

A soft dirt area of Mars would need to be dug out. The two battery powered ATV dozers would be operated for about two hours a day by two astronauts during the mid day and then plugged in to the solar array to recharge.

A surface solar array with 22 panels (22 panels of 250watts each would produce about 125 watts per panel on mars so a total of 2750 watts an hour) is mounted outside the buried hab. Also, the Long Range Rover can be plugged in to the main battery pack and supply 1kw an hour average to assist in charging the habitat batteries.

The Martian day is almost exactly the same as a day on earth so you should get 12 hours of sun every day unless there is a dust storm. Estimate about 27,500 watts of power a day from the solar panels, enough to charge both ATV's battery packs (13000 watts ea, 26000 total) and have power left over to operate the hab.

An external antenna receives messages from NASA.

Fruit trees grown: two peach, two plum, and two apple

Vegetables: potato's, lettuce, tomato's, bell peppers, mushrooms,

Long Term Buried Habitat Details:

The walls are made of fiberglass lego blocks that are 1' long, 6" tall, and 6" inches thick. Every block is sealed before being put in place but most of the lower wall sections are launched pre-assembled.

The floors are made of four 10'x10' by 6" thick fiberglass honeycomb panels each. The ends of the floor pieces fit in the lego wall blocks. The ceiling pieces connect to the top of the lego wall and they have grooves that the lower sleeping area fiberglass walls fit into.
There is a central fiberglass ladder tube that allows movement between levels and to the surface. The tube has a pressure door at the surface and a pressure door at the top of the upper level of the hab.

The buried hab has two carbon dioxide to oxygen systems, an oxygen bottle refill station. It also has an 80% recycle waste disposal, 90% water recycle wash sink, emergency carbon dioxide scrubbers, LED lighting, and there is one large emergency oxygen tank and many small, 3 min, portable oxygen canisters.

ATV Dozers:
Two 250 pound ATV dozers (weigh 125 lbs on Mars but the operator aboard adds weight) have steel tubular frames with steel rims and rubber pads for wheels. Three rechargeable deep cycle batteries provide power to two, 8hp, DC golf cart motors. The forward motor goes to a gearbox that powers both front wheels and the rear motor goes to a gearbox that powers both rear wheels. There is a switch for two rear wheel drive or four wheel drive.

The ATV dozers have a blade that can be raised and lowered electrically but the blade cannot be tilted otherwise. The blade can be fixed in the up position with pins. The batteries are in an enclosed container and they have a warmer to keep them from freezing. With a full charge the ATV dozers can operate at two wheel drive for about 15 miles before draining their batteries. The ATV dozers would be operated for an hour or so and then plugged in to the habitat solar array to recharge.

The ATV dozers have a small solar panel, 10 watt Mars, on top of the front cowling and another 20 watt Mars solar panel on the back cowling that supplements battery charging but these panels are not enough to completely recharge the batteries if they become completely drained.

The ATV dozers have a tow fitting on front for towing and on the back for pulling the other ATV or a wheeled cart.

RobertDyck · 2016-09-28 15:44:24

Sounds similar to other efforts. Food crops, NewMars thread: Crops

Mars Homestead Project - Phase 1, Hillside Settlement: Overview
This is a 10MB PowerPoint with 69 slides.

I was a member of the above project, so my bias will be toward that. The idea was to use landers about the size of Mars Direct, deliver crew and equipment. It would start with 12 crew members, each Mars Direct habitat accomodates 4 crew, so 3 Mars Direct habs. A 4th hab delivered as backup. Each Mars Direct hab would include a rover, the last one without crew would carry a skid-steer or mini-track loader instead. That's what you call an ATV dozer. It will have attachments: dozer blade, or front-end-loader bucket. A mini-track loader works better in loose soil, while a rubber tire skid-steer loader works better on hard ground or pavement. For the hillside settement, it would be operating on loose soil.

RobertDyck · 2016-09-28 15:48:55

A couple optimizations for trees. Any citrus fruit can be grafted onto any other citrus fruit. And there are dwarf orange trees that grow in a pot, the tree is small enough to grow indoors in your living room, although it would grow to the ceiling and completely fill your living room window. Still, that's small enough for a Mars greenhouse. You could graft a branch of lemon onto the orange tree. Similarly any apple can be grafted onto any other apple. And you can graft any stone fruit onto any stone fruit. One interesting exception is you can graft pear onto a variety of apple called "winter banana". You can graft a "scion" of winter banana onto an apple tree, then graft a scion of pear onto that. So you could have as few as 3 trees, yet a significant variety of fruit.

I live in Winnipeg, 60 miles (100km) north of the border with North Dakota. Winters are cold I planted a Goodland apple tree in my back yard. It's roughly 25 feet tall and just as wide. My property is 25' wide, the tree fills the back yard from fence to fence. It's really too big for my little yard. I am considering chopping it down. Nurseries say they now have a dwarf variety that only grows 8' tall, yet fruit is just as big. Obviously fewer apples. The apples are full size, as sweet as Macintosh and tart as crab apple at the same time. One thing about grafting, if the tree has crab apple roots, it will be more hardy, able to withstand colder climate, but apples from branches grafted onto it will always have some of the tartness of crab apple.

Dook · 2016-09-28 18:03:01

RobertDyck wrote:

Sounds similar to other efforts. Food crops, NewMars thread: Crops
Mars Homestead Project - Phase 1, Hillside Settlement: Overview
This is a 10MB PowerPoint with 69 slides.
I was a member of the above project, so my bias will be toward that. The idea was to use landers about the size of Mars Direct, deliver crew and equipment. It would start with 12 crew members, each Mars Direct habitat accomodates 4 crew, so 3 Mars Direct habs. A 4th hab delivered as backup. Each Mars Direct hab would include a rover, the last one without crew would carry a skid-steer or mini-track loader instead. That's what you call an ATV dozer. It will have attachments: dozer blade, or front-end-loader bucket. A mini-track loader works better in loose soil, while a rubber tire skid-steer loader works better on hard ground or pavement. For the hillside settement, it would be operating on loose soil.

I think the pictures of your settlement idea are beautiful but your timeline and the dependence on robots is way too optimistic. Signals from the Earth to Mars take somewhere around 18 minutes so you can't operate a robotic machine in real time. You would have to give it a command and then hope everything goes okay. If you tell a robotic dozer to dig out something there are just too many variables. What if it hits a rock? How is it going to know where the other robots are?

We don't even have robots that can operate completely independently on the earth, how would we do it on Mars? In another 50-75 years, maybe we would have some simple robots that could perform some functions, but with a more simple approach we could already have a small Mars habitat finished in that time.

What is going to power these robots? If it's solar then they would have maybe an hour of work time and then have to drive over to a large array and recharge the rest of the day.

It says the initial 4 settlers deploy, where do they deploy to? More people on Mars doesn't increase the chances of settlement success, it means more launches from earth to deliver oxygen, food, and water. Every launch from the earth that has oxygen, food, and water is one less launch of pre-made habitat and greenhouse building materials.

How many rocket launches is all of the mining, refining, and manufacturing equipment? Can you be more specific about the equipment needed to mine, refine, and manufacture? Why use a nuclear device? What about the radioactive particles that will be produced?

What are the standardized modules made of? The private/garage is the only one that seems to be the size of what a Mars Hab would be, the others are much larger so I assume they are sections that would be assembled on Mars. How are you going to move a Mars Hab section?

The building in the hillside have black walls and don't seem to be standardized modules, what are they made of? If they are bricks can you give details on the amount of water used in the making of these bricks?

I'm guessing it will take over 40 launches just for the buildings you have in your base. If we launched 2 a year it will take over 20 years to build your base, not counting oxygen, water, food, replacement parts, vehicles, solar panels, and people. And the oxygen, water, and food, take precedence over everything else.

Everything launched to Mars will land 50-100 miles away so someone is going to have to drive a long range rover out to get the supplies and tow them back to base. How are robots going to do this?

Your rover or truck picture doesn't use solar panels? What is it's power source? Where is the oxygen stored?

First we need a successful Mars in-situ sample return mission. Then a successful human mission to Mars and return home mission. Maybe after that we build some kind of starter base but the crews are going to return home for another 50 years or so. Manufacturing glass, steel, and aluminum on Mars will still be a futuristic idea 100 years from now.

There's no need to go to Mars. We're not abandoning the earth. Yes, we will have a Mars base eventually, slowly, one small step at a time, but we're not going to spend $500 billion a year on it. NASA's budget is about $18 billion a year and it's probably going to stay at that amount.

Last edited by Dook (2016-09-28 18:03:30)

Dook · 2016-09-28 18:16:13

RobertDyck wrote:

A couple optimizations for trees. Any citrus fruit can be grafted onto any other citrus fruit. And there are dwarf orange trees that grow in a pot, the tree is small enough to grow indoors in your living room, although it would grow to the ceiling and completely fill your living room window. Still, that's small enough for a Mars greenhouse. You could graft a branch of lemon onto the orange tree. Similarly any apple can be grafted onto any other apple. And you can graft any stone fruit onto any stone fruit. One interesting exception is you can graft pear onto a variety of apple called "winter banana". You can graft a "scion" of winter banana onto an apple tree, then graft a scion of pear onto that. So you could have as few as 3 trees, yet a significant variety of fruit.
I live in Winnipeg, 60 miles (100km) north of the border with North Dakota. Winters are cold I planted a Goodland apple tree in my back yard. It's roughly 25 feet tall and just as wide. My property is 25' wide, the tree fills the back yard from fence to fence. It's really too big for my little yard. I am considering chopping it down. Nurseries say they now have a dwarf variety that only grows 8' tall, yet fruit is just as big. Obviously fewer apples. The apples are full size, as sweet as Macintosh and tart as crab apple at the same time. One thing about grafting, if the tree has crab apple roots, it will be more hardy, able to withstand colder climate, but apples from branches grafted onto it will always have some of the tartness of crab apple.

I agree with your idea of using grafted trees to produce different kinds of fruit. I was too involved with the other aspects of the design. I actually have an orchard on my property and I didn't think of it.

The trees would have to be dwarf size for the buried hab. For a surface greenhouse you would use semi-dwarf. Some trees require two to cross pollinate, cherry trees need cross pollination, crab apple is another, so they probably wouldn't be the best choice for Mars.

Citrus trees would be fine for a buried habitat where the temperature is stable. If something happens and the temperature drops below freezing you kill your citrus tree whereas the other trees probably survive but they might go into dormancy.

RobertDyck · 2016-09-28 19:01:33

First, we debated several aspects of the settlement. I was one member of the team. I argued for greenhouses to be entirely ambient. That means greenhouses should not be buried, they would be illuminated directly by sunlight. Furthermore, I want greenhouses to be long and narrow, oriented perfectly east-west, with a flat mirror on either side the full length and same height as the greenhouse. Make the greenhouse twice as wide as it is tall. This means as much illumination from the mirrors as direct sunlight, so double illumination. Mars gets 47% as much sunlight as Earth, however not clouds. Double illumination means about the same as Earth. And long-narrow greenhouse means sunlight at dawn reflects a little further down the greenhouse, but still into the greenhouse. Sunlight at high noon reflects perfectly perpendicular. Sunlight at dusk reflects a little further the other way down the greenhouse, but still into the greenhouse. So no need to track the Sun. Angle of the mirrors will have to change with season, but only 1° change every 14 solar days (sols). That's so little change that an astronaut in a spacesuit could adjust a support rod; move to the next notch once every other week. Or automate if you can get a worm screw to operate reliably in Martian temperatures and dust environment.

But your major concern regarded robots. This would start with a rover operating with software similar to Spirit/Opportunity and Curiosity. That would move slow, but can navigate on its own. Drill for water to prove there is a reliable water source. Use ISPP to produce propellant, using the technique from Mars Direct. However, we would also produce oxygen and diluent gas to produce air for the habitat.

As for mining, you realize group of Canadian companies developed remote mining. That is operators stay on the surface while heavy equipment descends into the mine. Ensuring no one is actually in the mine means a collapse would cost millions of dollars, but no one would be killed. Mining companies quickly realized operators don't even have to be in the same city, they could use internet to relay commands from a major city like Toronto. One mining company went further, they developed a mine loader that operated entirely 100% by computer software; no operator. That could operate on Mars.

However, the goal was the mini-track loader would be operated by an astronaut. He would sit in the loader and dig out a cut in the side of the hill. Then construct the large, permanent habitat. When done, use the mini-track loader to push regolith (Mars soil) down from the hill down onto the settlement. This would provide counterweight to air pressure in masonry arches. This allows air pressure in arches without blowing out. I pointed out we would probably need some sort of sealant to ensure mortar joints don't leak. The regolith would also be radiation shielding.

Power for vehicles, including the loader, would be methane/oxygen. So the ISPP plant would provide fuel for vehicles.

In this image, notice the 4 white cylinders with a red ring painted around the top. Those are Mars Direct habitats. The first 4 astronauts would live in their Mars Direct habitat. The small pale blue things to the left of the habitats are inflatable greenhouses. One inflatable greenhouse per Mars Direct habitat. The larger pale blue things between the Mars Direct habitats and the hillside are greenhouses built with glass. The glass is made from Mars resources. The image shows the second pair are brown because they're covered in regolith (Mars soil). I argued for all greenhouses to have glass exposed to the sky for sunlight.

Habitat sections deep within the hillside are brick and mortar. Built with groin arches, an ancient Roman architecture. However, close to the hill edge the modules won't have regolith overpressure. So modules close to the hill edge, including all modules with doors or windows, are made of fibreglass.

You are right, we first need a robotic sample return mission to demonstrate ISPP. Then a science mission that returns to Earth. But notice the "construction shack" used for this base is the same as the surface habitat used for the science mission.

Furthermore, this base starts with 4, then 8, then 12 crew members. After that they double the base to receive another 12. With 24 crew members, they build a much larger base to receive 100 settlers. That is preparation for Elon Musk's colonial transport. He wants to deliver 100 settlers per ship.

Dook · 2016-09-28 20:11:46

RobertDyck wrote:

First, we debated several aspects of the settlement. I was one member of the team. I argued for greenhouses to be entirely ambient. That means greenhouses should not be buried, they would be illuminated directly by sunlight. Furthermore, I want greenhouses to be long and narrow, oriented perfectly east-west, with a flat mirror on either side the full length and same height as the greenhouse. Make the greenhouse twice as wide as it is tall. This means as much illumination from the mirrors as direct sunlight, so double illumination. Mars gets 47% as much sunlight as Earth, however not clouds. Double illumination means about the same as Earth. And long-narrow greenhouse means sunlight at dawn reflects a little further down the greenhouse, but still into the greenhouse. Sunlight at high noon reflects perfectly perpendicular. Sunlight at dusk reflects a little further the other way down the greenhouse, but still into the greenhouse. So no need to track the Sun. Angle of the mirrors will have to change with season, but only 1° change every 14 solar days (sols). That's so little change that an astronaut in a spacesuit could adjust a support rod; move to the next notch once every other week. Or automate if you can get a worm screw to operate reliably in Martian temperatures and dust environment.
But your major concern regarded robots. This would start with a rover operating with software similar to Spirit/Opportunity and Curiosity. That would move slow, but can navigate on its own. Drill for water to prove there is a reliable water source. Use ISPP to produce propellant, using the technique from Mars Direct. However, we would also produce oxygen and diluent gas to produce air for the habitat.
As for mining, you realize group of Canadian companies developed remote mining. That is operators stay on the surface while heavy equipment descends into the mine. Ensuring no one is actually in the mine means a collapse would cost millions of dollars, but no one would be killed. Mining companies quickly realized operators don't even have to be in the same city, they could use internet to relay commands from a major city like Toronto. One mining company went further, they developed a mine loader that operated entirely 100% by computer software; no operator. That could operate on Mars.
However, the goal was the mini-track loader would be operated by an astronaut. He would sit in the loader and dig out a cut in the side of the hill. Then construct the large, permanent habitat. When done, use the mini-track loader to push regolith (Mars soil) down from the hill down onto the settlement. This would provide counterweight to air pressure in masonry arches. This allows air pressure in arches without blowing out. I pointed out we would probably need some sort of sealant to ensure mortar joints don't leak. The regolith would also be radiation shielding.
Power for vehicles, including the loader, would be methane/oxygen. So the ISPP plant would provide fuel for vehicles.
http://www.marshome.org/images2/albums/Mars%20Homestead%20Project%20Effort/Mars%20Settlement%20Concept/normal_MHP-4FC-Image001.jpg
In this image, notice the 4 white cylinders with a red ring painted around the top. Those are Mars Direct habitats. The first 4 astronauts would live in their Mars Direct habitat. The small pale blue things to the left of the habitats are inflatable greenhouses. One inflatable greenhouse per Mars Direct habitat. The larger pale blue things between the Mars Direct habitats and the hillside are greenhouses built with glass. The glass is made from Mars resources. The image shows the second pair are brown because they're covered in regolith (Mars soil). I argued for all greenhouses to have glass exposed to the sky for sunlight.
Habitat sections deep within the hillside are brick and mortar. Built with groin arches, an ancient Roman architecture. However, close to the hill edge the modules won't have regolith overpressure. So modules close to the hill edge, including all modules with doors or windows, are made of fibreglass.
You are right, we first need a robotic sample return mission to demonstrate ISPP. Then a science mission that returns to Earth. But notice the "construction shack" used for this base is the same as the surface habitat used for the science mission.
Furthermore, this base starts with 4, then 8, then 12 crew members. After that they double the base to receive another 12. With 24 crew members, they build a much larger base to receive 100 settlers. That is preparation for Elon Musk's colonial transport. He wants to deliver 100 settlers per ship.

I kind of like the mirrored greenhouse walls idea for a surface greenhouse.

Robots that operate like Spirit and Opportunity are fine but they can only go from one place to another. They won't be able to excavate. ISSP propellant production requires a feedstock, so that would have to be delivered from the earth and you would have to drive out 50-100 miles to get it. How are you going to bring a large hydrogen tank back to the base?

Also, at first every launch to Mars is going to be return vehicles and astronaut explorers, return vehicles, explorers. This same pattern is going to be carried out at different places on Mars. Real settlement isn't going to begin for a long, long time. Elon Musk won't be alive when 100 settlers finally travel to Mars.

Astronauts in a Mars hab could remotely operate mining equipment? Sounds like a interesting idea. If your base has the 430 kw nuclear power plant that MIT proposed then you could have a number of excavation vehicles operating at the same time during the day and they could recharge at night. The excavation would have to be very close to the spot the Mars hab landed at or you would have to have television camera's on the excavation equipment.

Also, I think your idea of excavating into a hillside is better than my idea of excavating a pit but there's no way NASA is going to try to land a Mars Hab anywhere near a hill on Mars.

Your picture shows four Mars Habitats close together, how did you move them to that place?

Last edited by Dook (2016-09-28 20:13:41)

RobertDyck · 2016-09-28 22:27:10

I attended the 4th Canadian Space Exploration Workshop. That was organized by the Canadian Space Agency to set priorities for the next few years. This was November 2002, president of CSA was Marc Garneau. He wanted a Canadian rover to Mars, as big as Spirit or Opportunity. It would include a drill with 10 segments, each 1 metre long. Obviously fully automated, it would drill up to 10 metres below ground and pull up a "core". Marc hoped to partner with a country that has a launch vehicle: USA, Russia, or Europe. And hoped those partners we worked with in the past would contribute science instruments to analyze the core brought up. However, Canadian Parliament did not approve funding, so it didn't happen.

I envision this sort of rover sent to a location we believe to have ice. If and only if ice is found do we proceed with building a base. At the workshop, a university technology institute specializing in mining demonstrated the drill. They already had the drill. To do this today NASA could build such a rover, buy the drill from NORCAT: Northern Centre for Advanced Technology Inc.

Demonstrate you have an ice resource before sending anything else. Once you have a demonstrated, reliable ice resource, use that as source of hydrogen.

Robert Zubrin talked about legs for the Mars Direct habitat that could "walk" across terrain. We included those. It won't be quick, but will get the job done. Slide 8 showed possible landing locations that don't overfly the settlement. I keep hoping for landing much closer to the settlement. SpaceX is now able to land a Falcon 9 first stage on an ocean barge. My argument is to land only so far that rocks kicked up by landing rockets won't throw rocks into our base.

In 1990 Robert Zubrin argued for exploration with multiple missions using Mars Direct vehicles. Only once many locations have been scouted would he chose one for a permanent base. He argued for human explorers, not robotic ones. That was a valid argument for 1990. I argue that NASA has sent robotic explorers, so the task of scouting terrain has already been done. Done, completed, finished, over. What we need now is a robotic rover to confirm ice, then start the permanent base with the first human mission. If you wanted a vast human exploration program over vast areas of Mars before doing so, then it would have had to start in the 1990s. That wasn't done. Time has pissed away. Now it's time to start the permanent base. If you don't like that then you should have set human explorers to Mars in 1997, then 1999, etc. NASA could have done so if they just fulfilled the order of president George H. W. Bush in July 1989. But again, that didn't happen. Instead we had a series of orbiters and landers and robotic rovers. Now is the time to build the permanent base.

elderflower · 2016-09-29 03:16:21

We need to keep away from steep slopes. There are plenty of landslips on Mars and we need to do a lot of work on Martian slope stability before we can identify a good spot to burrow into. You will need to put your initial habs in the flatlands well away from hills. Conveniently, this is likely to be where the ice has collected, but we haven't got proof of that.

louis · 2016-09-29 03:49:39

Dook, I agree with your general approach...subterranean is the way forward for the early colony.

Some minor observations:

1. I think the quickest way to build is to have a trench dug (using a 1.5 tonne mini-digger with attached microwave to melt the soil) . Initially the trench might be covered with an imported roof and then covered with regolith. But soon the Mars colony should be able to make Mars bricks (low tech really) and build Roman arches, using standard struts for support as they are put in place. The arches can then be covered in regolith. Internally a Mars cement could be used to reduced air escape.

2. "The tube has a pressure door at the surface and a pressure door at the top of the upper level of the hab." Any more details. I think the pressure doors are some of the trickiest things to manufacture on Mars. Do you have any suggestions? I have wondered whether one might experiment with "ice doors" - effectively an ice barrier to the exterior or to the next chamber - which can be melted at will by microwave radiation beams. This is based on the understanding that the the natural permafrost layer remains frozen.

Dook · 2016-09-29 09:42:08

louis wrote:

Dook, I agree with your general approach...subterranean is the way forward for the early colony.
Some minor observations:
1. I think the quickest way to build is to have a trench dug (using a 1.5 tonne mini-digger with attached microwave to melt the soil) . Initially the trench might be covered with an imported roof and then covered with regolith. But soon the Mars colony should be able to make Mars bricks (low tech really) and build Roman arches, using standard struts for support as they are put in place. The arches can then be covered in regolith. Internally a Mars cement could be used to reduced air escape.
2. "The tube has a pressure door at the surface and a pressure door at the top of the upper level of the hab." Any more details. I think the pressure doors are some of the trickiest things to manufacture on Mars. Do you have any suggestions? I have wondered whether one might experiment with "ice doors" - effectively an ice barrier to the exterior or to the next chamber - which can be melted at will by microwave radiation beams. This is based on the understanding that the the natural permafrost layer remains frozen.

The Mars Habs that land on Mars will be the best habitats for astronauts to live in. The only reason to build another hab on Mars, at least in the beginning, is for a safety, in case something happens to the first Mars Hab. Also, you can't really grow plants inside the Mars Hab.

The trench idea doesn't work for me primarily because it would be just too much of an unusual space for humans to live in. Also, when digging a trench the walls have a tendency to collapse while you are digging and the excavator would have to have a very, very, long reach. A wide square area that is dug out with gently sloping sides won't collapse.

I don't think Mars bricks would be practical for a long time. You need a lot of water to make bricks, for water to exist on Mars you're going to need a pressurized area to bring Mars ice into so it can melt. To me, Mars ice is for drinking, not building bricks and not for rocket fuel.

Also, bricks are not the best building material for a buried structure. Brick/mortar structures have to stay in compression. A brick arch would be very strong. A vertical wall of bricks that supports a brick arch is not, any side pressure on the vertical wall and the whole thing comes down. I know Mars does not have quakes but regolith can still move.

You guys are in a hurry to establish a Mars Base but no one else is. The first planned human mission to Mars isn't going to be until 2035 and that mission is going to take at least a year minimum to complete.

Do I have any more details on the pressure door? Uhh, no, I was thinking of something like what you see in WW2 submarine movies, a circular hatch wide enough to go through in a Mars suit. I was thinking the door could be made of thick fiberglass with steel bars but maybe aluminum would be better than fiberglass for the hatch?

Getting through the permafrost could be difficult. Mars has less gravity so I tend to think that the regolith has settled and not compacted as much as we see on the earth. It may just be that you have to pick the right place to dig, a sandy spot.

louis · 2016-09-29 10:03:55

You seemed to have missed out on Musk's plans. He's looking at 2022 onwards, and - knowing Musk - I suspect he or his staff have been working on just such an issue as this.

If you look at Musk's work, you can see he is looking to land people in v. large transporter craft, but they can't all live inside the craft.

So how you provide habitat space quickly and safety is a big issue.

Permafrost trenches with the right geology don't collapse!

As on Earth, steel panels can be used to support the walls if necessary.

You've got no evidence for saying that regolith on Mars doesn't compact as much as on Earth. Remember, on Earth because of organic rock is constantly being degraded into loose soil. I think the Mars regolith will generally be more compacted that the Earth's land surface.

The air lock door issue is a big one, because of weight and need for specialist construction or import from Mars.

Dook wrote:

louis wrote:
Dook, I agree with your general approach...subterranean is the way forward for the early colony.
Some minor observations:
1. I think the quickest way to build is to have a trench dug (using a 1.5 tonne mini-digger with attached microwave to melt the soil) . Initially the trench might be covered with an imported roof and then covered with regolith. But soon the Mars colony should be able to make Mars bricks (low tech really) and build Roman arches, using standard struts for support as they are put in place. The arches can then be covered in regolith. Internally a Mars cement could be used to reduced air escape.
2. "The tube has a pressure door at the surface and a pressure door at the top of the upper level of the hab." Any more details. I think the pressure doors are some of the trickiest things to manufacture on Mars. Do you have any suggestions? I have wondered whether one might experiment with "ice doors" - effectively an ice barrier to the exterior or to the next chamber - which can be melted at will by microwave radiation beams. This is based on the understanding that the the natural permafrost layer remains frozen.
The Mars Habs that land on Mars will be the best habitats for astronauts to live in. The only reason to build another hab on Mars, at least in the beginning, is for a safety, in case something happens to the first Mars Hab. Also, you can't really grow plants inside the Mars Hab.
The trench idea doesn't work for me primarily because it would be just too much of an unusual space for humans to live in. Also, when digging a trench the walls have a tendency to collapse while you are digging and the excavator would have to have a very, very, long reach. A wide square area that is dug out with gently sloping sides won't collapse.
I don't think Mars bricks would be practical for a long time. You need a lot of water to make bricks, for water to exist on Mars you're going to need a pressurized area to bring Mars ice into so it can melt. To me, Mars ice is for drinking, not building bricks and not for rocket fuel.
Also, bricks are not the best building material for a buried structure. Brick/mortar structures have to stay in compression. A brick arch would be very strong. A vertical wall of bricks that supports a brick arch is not, any side pressure on the vertical wall and the whole thing comes down. I know Mars does not have quakes but regolith can still move.
You guys are in a hurry to establish a Mars Base but no one else is. The first planned human mission to Mars isn't going to be until 2035 and that mission is going to take at least a year minimum to complete.
Do I have any more details on the pressure door? Uhh, no, I was thinking of something like what you see in WW2 submarine movies, a circular hatch wide enough to go through in a Mars suit. I was thinking the door could be made of thick fiberglass with steel bars but maybe aluminum would be better than fiberglass for the hatch?
Getting through the permafrost could be difficult. Mars has less gravity so I tend to think that the regolith has settled and not compacted as much as we see on the earth. It may just be that you have to pick the right place to dig, a sandy spot.

RobertDyck · 2016-09-29 11:05:38

elderflower wrote:

We need to keep away from steep slopes. There are plenty of landslips on Mars and we need to do a lot of work on Martian slope stability before we can identify a good spot to burrow into. You will need to put your initial habs in the flatlands well away from hills. Conveniently, this is likely to be where the ice has collected, but we haven't got proof of that.

The issue is where ice is found. One reason for the Mars Homestead location was a hillside we could burrow into. Bruce Mackenzie wanted to build masonry arches, with regolith providing weight to counter air pressure. It's easier to push dirt down, hence the hillside. But the primary reason is where NASA has found ice. There is ice in the side walls of canyons at mid-latitudes. At that time NASA was adamant that the "floating pack ice" was just lava. Since then the European Space Agency has said no it isn't, that's pack ice covered in dirt. The floating pack ice is closer to the equator and flat, so may be a better location. But then you can't just push dirt down to burrow into a hillside.

NASA currently wants flat locations to land. However, SpaceX can land on a barge. You could start by landing a robotic rover at one of the flat landing zones of slide 8, drive over to the base location, and plant a landing beacon. Subsequent landers could home in on the beacon.

Antius · 2016-09-29 11:43:03

louis wrote:

2. "The tube has a pressure door at the surface and a pressure door at the top of the upper level of the hab." Any more details. I think the pressure doors are some of the trickiest things to manufacture on Mars. Do you have any suggestions? I have wondered whether one might experiment with "ice doors" - effectively an ice barrier to the exterior or to the next chamber - which can be melted at will by microwave radiation beams. This is based on the understanding that the the natural permafrost layer remains frozen.

How about a water filled airlock, rather like the U-bend of a toilet? On one side, pressure is ~300mbar and 50% O2. On the other side, pressure is a few KPa and is Martian atmosphere. A column of water maintains the differential pressure. To get out, you don your space suit, enter the water on the high pressure side (which has a shallow column) walk down to the u-bend and ascend a set of steps some 10m high before emerging from the water. At the top of the water column, the outside door would need a seal of sorts but it could be relatively low spec. A fan would blow Martian air into the top of the airlock to maintain a pressure of a few KPa. That stops the water boiling and freezing into ice. To exit, just equalise pressure at the top of the stairs with outside and open the door. The water will start to boil, but the fan will rapidly repressurise the space at the top of the stairs after the door closes.

Antius · 2016-09-29 12:01:25

louis wrote:

Dook, I agree with your general approach...subterranean is the way forward for the early colony.
Some minor observations:
1. I think the quickest way to build is to have a trench dug (using a 1.5 tonne mini-digger with attached microwave to melt the soil) . Initially the trench might be covered with an imported roof and then covered with regolith. But soon the Mars colony should be able to make Mars bricks (low tech really) and build Roman arches, using standard struts for support as they are put in place. The arches can then be covered in regolith. Internally a Mars cement could be used to reduced air escape.

The trench idea would appear to be the least resource intensive method creating pressurised living space. In terms of bricks for structural support, the best option may be compressed soil blocks. Take slightly damp clay-rich soil, sieve out heavy particles and compress it into a mould at 1000psi. You will have a brick about as strong as a regular house brick, though not as water resistant and far less water intensive than an adobe brick. You can form these into any shape you like; some quite complex interlocking designs have been made. These will provide the roof and internal structure that you need; even floors can be made in this way. When done, cover the whole structure will polyethylene and shovel the remaining regolith on top as a counterweight.

To make soil blocks you need a little water and a soil block machine. These will initially be imported from Earth, but are simple enough that they could be manufactured on Mars soon after the base is able to produce sheet steel.

louis · 2016-09-29 14:05:11

Antius,

Thanks for the reminder about compressed soil/regolith brick which is certainly deserving of some intensive research - if we could do away with the need to fire bricks, that must be a huge advantage.

louis · 2016-09-29 14:09:03

Antius, I hadn't thought a water lock would be possible but if so, then that definitely requires investigation.

One hopes Musk or his staff are also focussing on some of these crucial "unglamorous" issues.

Antius wrote:

louis wrote:
2. "The tube has a pressure door at the surface and a pressure door at the top of the upper level of the hab." Any more details. I think the pressure doors are some of the trickiest things to manufacture on Mars. Do you have any suggestions? I have wondered whether one might experiment with "ice doors" - effectively an ice barrier to the exterior or to the next chamber - which can be melted at will by microwave radiation beams. This is based on the understanding that the the natural permafrost layer remains frozen.
How about a water filled airlock, rather like the U-bend of a toilet? On one side, pressure is ~300mbar and 50% O2. On the other side, pressure is a few KPa and is Martian atmosphere. A column of water maintains the differential pressure. To get out, you don your space suit, enter the water on the high pressure side (which has a shallow column) walk down to the u-bend and ascend a set of steps some 10m high before emerging from the water. At the top of the water column, the outside door would need a seal of sorts but it could be relatively low spec. A fan would blow Martian air into the top of the airlock to maintain a pressure of a few KPa. That stops the water boiling and freezing into ice. To exit, just equalise pressure at the top of the stairs with outside and open the door. The water will start to boil, but the fan will rapidly repressurise the space at the top of the stairs after the door closes.

GW Johnson · 2016-09-29 15:53:05

Water lock in lieu of air lock: Discount for now the risk of the water freezing. The excess water height on the low-pressure side is related to the difference of pressures between the two sides. Your U-bend dimension must be larger than that by at least a diameter or so.

Density x gravity x depth = delta-pressure. So depth = delta-pressure/(density x gravity). On Earth at 1013 mbar = 1 atm = 14.7 psia, with vacuum on the other side, a fresh water column is 33 ft (about 10 m) tall. That's at 1 gee worth of gravity. Mars has 0.38 gee worth of gravity, so 1 atm difference corresponds to 87 ft = 26.5 m on Mars.

If you reduce the habitat air pressure to a fraction of an atmosphere, that same fraction multiplies your water column height. But reduced pressure requires higher oxygen concentration, for which there are health and fire risks.

If you are going outside in a pressure suit anyway, use a denser liquid. I can think of two: mercury and gallium. Mercury is 13.54 times as dense as water, the same 1 atm column on Mars would be 23.54 times shorter, or about 2 m. I do not know what temperature mercury freezes. It is a bit toxic if you heat it, though.

Gallium sg = 5.9. That column would be about 4.5 m. To keep it liquid requires about 98F. Toxicity questions unknown.

GW

Terraformer · 2016-09-29 16:11:34

It's been suggested before, and I really think it would be a good idea - a low pressure paraterraformed section of Mars. Maybe 50mb, used for growing crops and aquaculture. Place your main hab inside that one, possibly at the bottom of the lake.

Antius · 2016-09-29 16:13:09

26.5m is a lot of water. To prevent freezing would require either heating the water (which would push up partial pressure) or using brine. If we are using mcp suits, the evaporation of water trapped within the fabric would lead to frost bite upon entering the outside air. Maybe not such a good idea after all.

Tom Kalbfus · 2016-09-29 22:46:15

What if we unrolled a Stanford Torus?
Total mass: 10 million tons (including radiation shield (95%), habitat, and atmosphere)
Diameter: 1,790 m (1.11 mi)
Habitation tube diameter: 130 m (430 ft)
Spokes: 6 spokes of 15 m (49 ft) diameter
Rotation: 1 revolution per minute
Radiation shield: 1.7 meters (5.6 feet) thick raw lunar soil
Figure5.23_Stanford_torus_structural_cross_section.gif
This is the relevant part of the Stanford Torus that we can replicate on Mars. Since the Stanford Torus is 1790 meters in diameter, to "unroll" it on the surface of Mars, you would get a linear "greenhouse" that is 5624 meters long, it remains 130 meters wide. I don't know what the six spokes would be used for, they would each be 895 meters high, each one would be taller than the World Trade Center. We can orient the station in the North-South direction along the equator and place mirrors on either side to double the amount of sunlight to Earth normal levels. residents would see two small suns in the sky rise in the east and set in the west.

kbd512 · 2016-09-30 01:21:13

Why not use a tunnel boring machine (TBM) of some reasonable diameter, like 5M or so? The cutting heads themselves aren't too heavy. The support equipment train is the major portion of the TBM's weight. If the TBM had its own nuclear power supply built into it, it might weigh 20t or so. The equipment train is unnecessary if the holes are bored vertically to a shallow depth of between 10M and 15M. The sides of the tunnel could be sintered smooth using heat from the reactor. Relatively light and compact kevlar inflatables of the type created by Bigelow Aerospace could then be placed into the holes, pressurized, and then some regolith could be pushed over the top of the habitat.

5M of Martian regolith is roughly equivalent to the protection that Earth's atmosphere provides for us, so sleeping 10M down should provide substantial radiation protection. Does anyone here know whether or not a kevlar inflatable pressurized to SL could withstand the dead load of 3M to 5M of regolith placed over the top of it, assuming a 5M diameter with a 1.5M diameter vertical airlock in the center of each module?

Horizontally oriented modules have their own set of issues. Covering the modules with regolith requires resistance to a greater total dead load or less radiation protection, airlocks / piping / cabling still have to be connected and buried to avoid accidents with rovers or earth movers, and the connections may also be longer than they'd otherwise be with vertical orientation.

After the TBM is done boring holes for habitation modules, it could then bore a hole for itself to serve as the colony's power plant. Smaller holes could be bored between vertical module pits so airlocks, plumbing, and cabling could be connected to individual modules. This would enable creation of specialty modules for water storage and reprocessing, atmospheric control, galley and food storage, medical facility, computers and communications, laboratory, greenhouse, equipment repair facility, gym, etc.

Heavy equipment and consumables, sensitive electronics, and medical machines like MRI's could be placed at the bottom level of the vertically oriented modules. The lower levels would also serve as solar storm shelters and sleeping quarters. The upper levels would be for lighter equipment, workshops, and living space.

You don't need a crane to lift a small TBM. It's can be mounted in a ring that is raised and lowered by two electrically powered Swedish S-Tanks that have been modified for use on Mars (no gun / armor / fuel tanks, hydraulics replaced with electrical servos, etc). The tanks can connect themselves to the TBM mounting bracket on opposite ends to position the tool over the boring site. For those who are not familiar with this tank, S-Tanks can precisely adjust their tracks electrically or hydraulically to pitch up and down (and potentially side-to-side as well) and come equipped with dozer blades mounted on the front. The basic idea is to combine the construction equipment with the power plant to reduce the number of pieces of equipment to deliver, minimize construction setup and operations time, and to maximize their utility to the colony in other ways.

This is just an idea and may not be feasible. There may well be some kind of showstopper I don't know about.

Tom Kalbfus · 2016-09-30 08:21:17

How about building a hab next to a canyon wall of the Vallis Marineris, that should provide some radiation protection.

Last edited by Tom Kalbfus (2016-09-30 08:21:59)

Terraformer · 2016-09-30 13:02:08

Antius wrote:

26.5m is a lot of water. To prevent freezing would require either heating the water (which would push up partial pressure) or using brine. If we are using mcp suits, the evaporation of water trapped within the fabric would lead to frost bite upon entering the outside air. Maybe not such a good idea after all.

One could of course wear a dry suit for entering and exiting...

Dook · 2016-09-30 16:51:13

Louis: You're under the impression that an air lock has to be manufactured on Mars. It doesn't. Instead of taking 100 people to Mars, which is absolutely ridiculous, just take 98 and use the weight savings for the pressure doors. Problem solved easily.

Can you all come back to reality or are you hopelessly lost in Elon Musk's science fiction fantasyland?

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