Like Every. Freaking. Architect. Proposal ever, they don’t quite grasp that the habs will be stiffer than a basketball and can’t have nice, convenient flat floors. The fat solowheels are kinda stupid too, as shown, they can’t turn unless hooked up with another unit- and then they’ll scrub their treads off quickly. The freestanding cosmic ray shield IS a good idea, though, but I’d want to put some rebar in there to prevent catastrophic failure in the event of Marsquakes. (Mars does not seem to have a lot of quakes though.)
But, but, inflatable domes only need a tiny fraction of a psi to stay up!
Assuming the inside is only at about Denver’s pressure, the flat floor of a 20′ diameter Mars dome only has to stay rigid against a distributed load of about 250 tonnes, which is no more than the weight of four M1A1 Abrams tanks piled on top of each other. Surely pine 2×10’s on 18″ centers will do fine!
It’s probably been suggested by someone, but one easy way to gain radiation shielding would be to land something like a Falcon vertically on one of the ice caps, which can almost guarantee a flat horizontal landing surface. Then heat the base to melt into the ice, and let the cylindrical rocket slide down through a ring that mounts the landing legs. As the top end of the rocket reaches the landing leg’ mounting ring, it would catch on a lip that marks the ingress/egress part of the descent vehicle, so the final depth would be easily controlled.
The would provide easy radiation shielding for the lower interior, but also create the problem of a rather inconvenient geographical location for anything other than turning water ice into fuel.
Another possibility is of course just to melt and pump water, spraying it over the habitat where it freezes.
“Another possibility is of course just to melt and pump water, spraying it over the habitat where it freezes.”
Water ice sublimes at martian temperatures and pressures. I guess you could continually pump more water if you have a lot of it, but good old-fashioned dirt seems like a better plan.
We thus find that a 1‐m thick layer of ice buried below a meter of regolith resembling JSC Mars‐1 on Mars at 235 K would last ∼800 years.
Yup, but “spraying” and “1 meter regolith” are not compatible concepts.
True, but the paper was investigating the idea of using wateri ice for shielding and then figuring out how much regolith would need to be on top to keep sublimation in check. A few inches made a big difference.
Of course the snag is setting up a drilling rig to extract the water, along with pumps, hoses, etc. It sort of assumes that an ISRU infrastructure is already in place.
Water ice also condenses at martian temperatures and pressures.
What the balance is between sublimation and condensation depends largely on latitude.
Using ice for shielding Martian habs is an excellent idea. Whether that might be burrowing into a polar surface glacier or ice reinforcement of an inflated dome near the equator.
Why use it for shielding, when it is far more valuable ask feedstock for making rocket fuel?
Why is the polar ‘geographic’ location (what is the martian term for geographic?) inconvenient? The Martian North Polar region might be the most valuable real estate on Mars!
Geoffrey Landis has interesting ideas describing the advantages of a Polar landing site for Mars operations, such as launch windows and summer solar power.
I’d just cover a crater or partially collapsed lava/water tube after clearing out all the dirt down to bedrock. Initially, you could just have a mobile hab and back it into one of these openings if cosmic rays are a big worry.
If there’s high confidence of accessible water sources, the simplest way to provide radiation shielding is to send a double-wall habitat, such as nested spheres, and pump ground water in between the inner and outer one.
If the inside was 20 feet in diameter and the gap between hulls was three feet, it would hold 130 tons of ice with an R-value of 27. Put about 4 inches of good foam insulation on the inside wall and it should only take about a kilowatt to keep it warm, while keeping the inner side of the ice well below freezing. If you went with four feet of ice it would take 200 tons to fill, and with six inches of internal foam it would only take about 800 watts to heat, and a four person crew and their personal equipment would probably provide that much.
For crafting an artificial Martian ice cave, instead of nested spheres and pumping in liquid water, I think you could exploit the natural cycles of Mars to make the cave for you.
First you land a inflatable structure near the equatorial zone of Mars. The structure is a basic dome shape, with a flat floor. The interior can be made gas tight, but is kept at Mars surface level pressure. The dome shape is supported by inflatable ribs built into the wall. During the daytime the Dome is buttoned up sealing it off from the Martian air. After midnight the Dome is opened up to the Martian air, allowing free flow.
At sunset as the air rapidly cools, inside the Dome ice will begin to condense out of the air, the ice accumulating on the inside surfaces. At sunrise, the air inside the Dome is trapped, even if ice sublimates during the day, it remains trapped inside the Dome.
Each day, more and more ice would accumulate on the Interior Dome surface. The larger the Dome the more efficient the building of the ice layer would become, since the surface area of the dome increases more slowly than the interior volume of the air.
What this Dome does is exploit the Mars diurnal cycle to replicate and accelerate the ice transport mechanisms of the Martian seasons which create the permanent polar ice caps.
What’s nice about my scheme is how simple the whole system is. No complicated harvesting equipment. No heavy electric equipment for heating or condensing ice. No robots for constructing a building.
However, I have no idea yet how quickly the ice would accumulate. Maybe the idea falls apart because the whole process would be too slow?
The UniHab concept at DevelopSpace.info envisions a singular, large, inflatable habitat with a roof & floor made flat using internal tethers and walls. A flat roof would hold regolith telerobitically pushed on top prior to inflation. No need for numerous robots or power-hungry and prone to break due 3D printing. Also, if one starts with shipping just the outer layer of a large habitat followed by separately shipping the inner layers then acres of footprint could be established.
I think I’ve seen that, and it’s a good idea, especially in a relatively sandy, rock free area.
I also like the idea of using a back shell as the roof, with the lander flipping upside down for the final landing burn.
Are you forgetting that the company that will probably get there first, also builds boring machines, flame throwers, and electric cars?
How large would a solar array need to be, at the martian surface, or Lunar surface, to power an underground habitat for a hundred people, and connected by tunnel to other habitats?
This would apply to any colony inside of Jupiter’s orbit.
And how long would a battery bank be expected to last in case of global dust storms?
–Art
April 28, 2019 At 6:00 AM
Are you forgetting that the company that will probably get there first, also builds boring machines, flame throwers, and electric cars?
How large would a solar array need to be, at the martian surface, or Lunar surface, to power an underground habitat for a hundred people, and connected by tunnel to other habitats?–
I think a settlement and an exploration base are different topics.
I think an exploration base should start with 3 crew and quickly move to 6 crew, and doesn’t need to have more than 12 crew.
And if have at any point more than 12 crew on Mars surface, it’s because you a number of different bases in different locations.
A settlement should start with dozens and the site should future potential of supporting more than 1000 people. A settlement is modern living- grid power, water, sewage, and a spaceport and other transportional infrastructures.
So exploration is camping and settlement is living somewhere.
Exploration is living there for few years, settlements are designed with hundred year lifetimes and designed to allow for population growth. Population growth in future is essential for any settlement, otherwise it almost like planning for ghost towns [mining towns, logging camps, beach houses, etc {temporary}].
It’s possible [though not likely or advisable] that settlements could be mobile. But a mobile base for exploration purpose is more possible or could be a good idea. A mobile exploration base might be always moving or it could be that it’s merely designed so that in future one might move it once or twice [or recycle the building structures] for use in different location.
I wonder if there’s a far more minimalist approach to the exploration phase, but I’ll have to run mass numbers to see if it would make sense to basically commute to the surface and back for the EVA’s, virtually dispensing with an actual lander that can be used for much of anything.
That they’ve made it to Mars means the ship in orbit already has radiation shielding, and that’s what makes medium duration stays on the surface problematic, along with tying an exploration crew to a very small accessible area. A “flying rover” that drops them on the surface for a 12 hour stay before returning them to the ship might be an interesting approach, depending on how the mass numbers look.
The size of the solar array of course depends on if they’re trying to power an LED greenhouse. Compared to everything else they need to land, a large solar array probably isn’t a significant problem.
If anyone can land a decent sized tunnel boring machine on Mars then they probably don’t need a tunnel because they could just live in the boring machine. A recent 7-foot diameter hard rock machine used in Youngstown weighed 150,000 lbs. Certainly aerospace materials could cut that way down, but that’s still only cutting a hole big enough for a walkway. A TBM might be something best build on site long after development is underway. Tunneling into ice, however, is really easy, but again raises the problem of trying to develop the least hospitable area on the whole planet.
Landing in an steep east-west (for sunlight) river channel that blocks out half the sky is a quick way to cut cosmic rays in half, but the views aren’t going to be the best.
A Starship could put a couple backhoes on the Martian surface though.
If a tunnel boring machine is 75 tons, a starship could put one on any planet inside of Jupiter, and probably on any moon of even Saturn. Everything I’ve seen so far talks about a lot of infrastructure already moved into place. It’s not there yet. We need to put it there. I believe one starship can provide all equipment necessary for building habitats, and the second one can deliver some of the equipment needed to start producing fuel. Third, we need a source of energy. Solar panels and batteries, combined with a power plant that works when the sun isn’t shining. Then we need people. Lots of people. All these plans of putting a few astronauts on a distant body belong in the history books. 3, 5, or 7 people can make a documentary before they return to earth. If we are serious, it will take hundreds initially, and millions eventually. The sooner the better. Oh, and plan for duplicate flights, because you will lose some of them. Anything else is just thinking like NASA; talk a lot, spend a lot, and don’t go anywhere unless you absolutely have to.
Hrm… A Mars-rated backhoe.
The lower gravity is going to cause some differences. Lifting is two and a half times easier, but pushing forward or trying to dig down into the surface will probably have just as much resistance as here, but with a vehicle that only weighs 38% as much as normal to provide traction and downward force. Balance might mean the bucket size will stay the same for scooping, but the dipper might need to be smaller because of the reduced available weight of the vehicle to push it.
The low pressure and extremely low temperatures will of course cause problems for hydraulic fluids and lubricants. I figure they’ll stick with Castrol Braycote for grease, since it’s well proven in Mars rovers. They could try the Space Shuttle’s hydraulic fluid (MIL-H-83282) or perhaps a low-vapor pressure lubricant like Pennzane X-1000 or X-2000. (NASA paper).
Avoiding a hydraulic leak is going to be critical to mission success, so they might want to pick a good low-temperature material for the O-rings or just operate the backhoe around noon during the summer until overridden by management.
Like Every. Freaking. Architect. Proposal ever, they don’t quite grasp that the habs will be stiffer than a basketball and can’t have nice, convenient flat floors. The fat solowheels are kinda stupid too, as shown, they can’t turn unless hooked up with another unit- and then they’ll scrub their treads off quickly. The freestanding cosmic ray shield IS a good idea, though, but I’d want to put some rebar in there to prevent catastrophic failure in the event of Marsquakes. (Mars does not seem to have a lot of quakes though.)
But, but, inflatable domes only need a tiny fraction of a psi to stay up!
Assuming the inside is only at about Denver’s pressure, the flat floor of a 20′ diameter Mars dome only has to stay rigid against a distributed load of about 250 tonnes, which is no more than the weight of four M1A1 Abrams tanks piled on top of each other. Surely pine 2×10’s on 18″ centers will do fine!
It’s probably been suggested by someone, but one easy way to gain radiation shielding would be to land something like a Falcon vertically on one of the ice caps, which can almost guarantee a flat horizontal landing surface. Then heat the base to melt into the ice, and let the cylindrical rocket slide down through a ring that mounts the landing legs. As the top end of the rocket reaches the landing leg’ mounting ring, it would catch on a lip that marks the ingress/egress part of the descent vehicle, so the final depth would be easily controlled.
The would provide easy radiation shielding for the lower interior, but also create the problem of a rather inconvenient geographical location for anything other than turning water ice into fuel.
Another possibility is of course just to melt and pump water, spraying it over the habitat where it freezes.
“Another possibility is of course just to melt and pump water, spraying it over the habitat where it freezes.”
Water ice sublimes at martian temperatures and pressures. I guess you could continually pump more water if you have a lot of it, but good old-fashioned dirt seems like a better plan.
I had to look that up.
Wiley online library article
Yup, but “spraying” and “1 meter regolith” are not compatible concepts.
True, but the paper was investigating the idea of using wateri ice for shielding and then figuring out how much regolith would need to be on top to keep sublimation in check. A few inches made a big difference.
Of course the snag is setting up a drilling rig to extract the water, along with pumps, hoses, etc. It sort of assumes that an ISRU infrastructure is already in place.
Water ice also condenses at martian temperatures and pressures.
What the balance is between sublimation and condensation depends largely on latitude.
https://arxiv.org/pdf/0903.2688.pdf
Using ice for shielding Martian habs is an excellent idea. Whether that might be burrowing into a polar surface glacier or ice reinforcement of an inflated dome near the equator.
Why use it for shielding, when it is far more valuable ask feedstock for making rocket fuel?
Why is the polar ‘geographic’ location (what is the martian term for geographic?) inconvenient? The Martian North Polar region might be the most valuable real estate on Mars!
Geoffrey Landis has interesting ideas describing the advantages of a Polar landing site for Mars operations, such as launch windows and summer solar power.
http://www.geoffreylandis.com/pole.html
Areographic.
I’d just cover a crater or partially collapsed lava/water tube after clearing out all the dirt down to bedrock. Initially, you could just have a mobile hab and back it into one of these openings if cosmic rays are a big worry.
If there’s high confidence of accessible water sources, the simplest way to provide radiation shielding is to send a double-wall habitat, such as nested spheres, and pump ground water in between the inner and outer one.
If the inside was 20 feet in diameter and the gap between hulls was three feet, it would hold 130 tons of ice with an R-value of 27. Put about 4 inches of good foam insulation on the inside wall and it should only take about a kilowatt to keep it warm, while keeping the inner side of the ice well below freezing. If you went with four feet of ice it would take 200 tons to fill, and with six inches of internal foam it would only take about 800 watts to heat, and a four person crew and their personal equipment would probably provide that much.
For crafting an artificial Martian ice cave, instead of nested spheres and pumping in liquid water, I think you could exploit the natural cycles of Mars to make the cave for you.
First you land a inflatable structure near the equatorial zone of Mars. The structure is a basic dome shape, with a flat floor. The interior can be made gas tight, but is kept at Mars surface level pressure. The dome shape is supported by inflatable ribs built into the wall. During the daytime the Dome is buttoned up sealing it off from the Martian air. After midnight the Dome is opened up to the Martian air, allowing free flow.
At sunset as the air rapidly cools, inside the Dome ice will begin to condense out of the air, the ice accumulating on the inside surfaces. At sunrise, the air inside the Dome is trapped, even if ice sublimates during the day, it remains trapped inside the Dome.
Each day, more and more ice would accumulate on the Interior Dome surface. The larger the Dome the more efficient the building of the ice layer would become, since the surface area of the dome increases more slowly than the interior volume of the air.
What this Dome does is exploit the Mars diurnal cycle to replicate and accelerate the ice transport mechanisms of the Martian seasons which create the permanent polar ice caps.
What’s nice about my scheme is how simple the whole system is. No complicated harvesting equipment. No heavy electric equipment for heating or condensing ice. No robots for constructing a building.
However, I have no idea yet how quickly the ice would accumulate. Maybe the idea falls apart because the whole process would be too slow?
The UniHab concept at DevelopSpace.info envisions a singular, large, inflatable habitat with a roof & floor made flat using internal tethers and walls. A flat roof would hold regolith telerobitically pushed on top prior to inflation. No need for numerous robots or power-hungry and prone to break due 3D printing. Also, if one starts with shipping just the outer layer of a large habitat followed by separately shipping the inner layers then acres of footprint could be established.
I think I’ve seen that, and it’s a good idea, especially in a relatively sandy, rock free area.
I also like the idea of using a back shell as the roof, with the lander flipping upside down for the final landing burn.
Are you forgetting that the company that will probably get there first, also builds boring machines, flame throwers, and electric cars?
How large would a solar array need to be, at the martian surface, or Lunar surface, to power an underground habitat for a hundred people, and connected by tunnel to other habitats?
This would apply to any colony inside of Jupiter’s orbit.
And how long would a battery bank be expected to last in case of global dust storms?
–Art
April 28, 2019 At 6:00 AM
Are you forgetting that the company that will probably get there first, also builds boring machines, flame throwers, and electric cars?
How large would a solar array need to be, at the martian surface, or Lunar surface, to power an underground habitat for a hundred people, and connected by tunnel to other habitats?–
I think a settlement and an exploration base are different topics.
I think an exploration base should start with 3 crew and quickly move to 6 crew, and doesn’t need to have more than 12 crew.
And if have at any point more than 12 crew on Mars surface, it’s because you a number of different bases in different locations.
A settlement should start with dozens and the site should future potential of supporting more than 1000 people. A settlement is modern living- grid power, water, sewage, and a spaceport and other transportional infrastructures.
So exploration is camping and settlement is living somewhere.
Exploration is living there for few years, settlements are designed with hundred year lifetimes and designed to allow for population growth. Population growth in future is essential for any settlement, otherwise it almost like planning for ghost towns [mining towns, logging camps, beach houses, etc {temporary}].
It’s possible [though not likely or advisable] that settlements could be mobile. But a mobile base for exploration purpose is more possible or could be a good idea. A mobile exploration base might be always moving or it could be that it’s merely designed so that in future one might move it once or twice [or recycle the building structures] for use in different location.
I wonder if there’s a far more minimalist approach to the exploration phase, but I’ll have to run mass numbers to see if it would make sense to basically commute to the surface and back for the EVA’s, virtually dispensing with an actual lander that can be used for much of anything.
That they’ve made it to Mars means the ship in orbit already has radiation shielding, and that’s what makes medium duration stays on the surface problematic, along with tying an exploration crew to a very small accessible area. A “flying rover” that drops them on the surface for a 12 hour stay before returning them to the ship might be an interesting approach, depending on how the mass numbers look.
The size of the solar array of course depends on if they’re trying to power an LED greenhouse. Compared to everything else they need to land, a large solar array probably isn’t a significant problem.
If anyone can land a decent sized tunnel boring machine on Mars then they probably don’t need a tunnel because they could just live in the boring machine. A recent 7-foot diameter hard rock machine used in Youngstown weighed 150,000 lbs. Certainly aerospace materials could cut that way down, but that’s still only cutting a hole big enough for a walkway. A TBM might be something best build on site long after development is underway. Tunneling into ice, however, is really easy, but again raises the problem of trying to develop the least hospitable area on the whole planet.
Landing in an steep east-west (for sunlight) river channel that blocks out half the sky is a quick way to cut cosmic rays in half, but the views aren’t going to be the best.
A Starship could put a couple backhoes on the Martian surface though.
If a tunnel boring machine is 75 tons, a starship could put one on any planet inside of Jupiter, and probably on any moon of even Saturn. Everything I’ve seen so far talks about a lot of infrastructure already moved into place. It’s not there yet. We need to put it there. I believe one starship can provide all equipment necessary for building habitats, and the second one can deliver some of the equipment needed to start producing fuel. Third, we need a source of energy. Solar panels and batteries, combined with a power plant that works when the sun isn’t shining. Then we need people. Lots of people. All these plans of putting a few astronauts on a distant body belong in the history books. 3, 5, or 7 people can make a documentary before they return to earth. If we are serious, it will take hundreds initially, and millions eventually. The sooner the better. Oh, and plan for duplicate flights, because you will lose some of them. Anything else is just thinking like NASA; talk a lot, spend a lot, and don’t go anywhere unless you absolutely have to.
Hrm… A Mars-rated backhoe.
The lower gravity is going to cause some differences. Lifting is two and a half times easier, but pushing forward or trying to dig down into the surface will probably have just as much resistance as here, but with a vehicle that only weighs 38% as much as normal to provide traction and downward force. Balance might mean the bucket size will stay the same for scooping, but the dipper might need to be smaller because of the reduced available weight of the vehicle to push it.
The low pressure and extremely low temperatures will of course cause problems for hydraulic fluids and lubricants. I figure they’ll stick with Castrol Braycote for grease, since it’s well proven in Mars rovers. They could try the Space Shuttle’s hydraulic fluid (MIL-H-83282) or perhaps a low-vapor pressure lubricant like Pennzane X-1000 or X-2000. (NASA paper).
Avoiding a hydraulic leak is going to be critical to mission success, so they might want to pick a good low-temperature material for the O-rings or just operate the backhoe around noon during the summer until overridden by management.