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You think the settlers are going to make methane? Not in the habitat they're not. That would be like bringing gasoline inside your house so you can mess around with it. Any Sabatier processing would be done in a completely separate module by a machine.
There would be small amounts of methane in the habitat from the humans but the activated charcoal filters should take care of that.
A rover could slam into a hab at speed? Uhh, okay, if it's on the surface.
We can't really know all the risks? We kind of do know all the risks that's why we're taking years to study the problems and find solutions.
There is contamination on robot rovers? Other than the very extreme bacteria any other bacteria on a robot rover would die on the space trip over or die on Mars.
Could there be some kind of bacteria on something that makes it into the habitat? Sure, there could but it's not going to be any different than the Earth and we're not over run with bacteria problems here.
I can't think of a single life support component that is made of glass.
And, if you're thinking of making glass greenhouse panels, well, you can't bolt glass to anything, it's too brittle. It will shatter. So you can't make your greenhouse out of only glass panels.
You could make the greenhouse panels out of very strong plastic and bond a layer of glass to the outside of the strong plastic and bolt the plastic panels to each other. The glass on the outside would give the panels some weight to resist the internal pressurization that would be trying to lift the domed greenhouse from the ground.
The thing about needing all this power is it's only needed to recharge the Marscats for 21 days of digging, then they would build the habitats, then it might take them 10 days or so to bury the habitats with the Marscats.
Is there any way to reduce the size of the SAFE-400 to a smaller version that puts out about 15,000 to 20,000 watts? Or is it as small as it can get?
Also can you insert the control rod to activate it for a month or so, then pull out the control rod to deactivate it when it's no longer needed? Isn't that how nuclear power reactors work?
The crew could activate the smaller SAFE-400 for a month to recharge the Marscats. Dig out the habitat area, build the habitats, bury them, recharge the Marscats and deactivate the reactor.
Then, a year or so later, they would get a second shipment of buried habitat components and reactivate the SAFE-400 for a month to recharge the Marscats again.
When you did your plant energy study did you factor in reflected light?
Also, plants on the earth don't get a full 24 hours of sunlight, they get about 12 hours if they are grown in a field that has been cleared.
If you can't grow plants inside then how come all these people are growing marijuana in their garages?
The only reason you need a lot of power is to make rocket fuel on Mars. It's a waste of time and energy to try to gather Mars salty ice to turn into fresh water that you then zap into rocket fuel. It's even more wasteful to try to produce steel, aluminum, glass, or other materials that don't provide more food, oxygen, or water.
Any exploration team will have a landed ERV to return home on. A settlement should not have to make rocket fuel because they should stay on Mars. Even if you do bring them home you would send them an ERV to come home in like the exploration teams would use.
We only need to power the Mars Hab, recharge the rovers, and power a buried habitat. We don't need a large nuclear reactor. We need a large RTG capable of about 15,000 watts an hour supplemented by solar arrays on the surface (two 10'x50' arrays, not a 300'x300 foot one), another array on top of the Mars Hab (30' circular to cover the regolith), and a thin solar array built in to the outside of the Mars Hab (maybe 360 watts an hour).
Growing inside will be energy intensive? Seven buried 25' circular habitats could have five 23 watt (100 watt equivalent) LED lights each. The inside walls, ceiling, and floor would be white to reflect light. That's 115 watts an hour per habitat, 805 total watts, for growing plants.
I found it, the Sandia Report 50-100 kwe gas cooled reactor. I just don't like all the moving parts compared to an RTG.
The two Marscat would use 268,560 watts total working 3 hours a day. So, they need 12,788 watts total recharge an hour to be fully recharged. So, we need to produce about 15,000 watts an hour of power all night long.
The Buk RTG makes 3,000 watts and weighs 2,200 lbs. If we increased it 5 times it would produce 15,000 watts an hour and weigh 11,000 lbs.
One Marscat uses 134,280 watts in 3 hours of use. Two Marscats would use a total of 268,560 watts in 3 hours of use.
So, if you use the Marscats for 3 hours a day and recharge them for 21 hours a day they both need a combined 12,788 watts per hour to recharge and be ready the next day. That's a problem.
I think a big RTG would produce 600 watts an hour, two 10'x50' thin solar arrays would produce about 450 watts each (900 total), a thin solar array on the top of the Mars Hab covering the regolith would produce another 635 watts an hour, and a solar array on the entire outside of the Mars Hab would produce about 360 watts an hour. So, that's a total of 2,095 watts produced every hour in the day, and 600 watts an hour at night. That's not going to be enough.
How much power would a small nuclear reactor generate?
I think some time ago Spacenut posted a link to a nuclear reactor that was 30 feet wide.
Dook wrote:If the trips were kept to only 5 minutes the rover could have one lithium-ion battery.
Yes, it could be low powered, but I guess we have to plan for the unexpected...the air lock malfunction that keeps them out in the open for an hour say.
Dook wrote:The electric motor could be 10 hp and go to a golf cart type axle that powers both rear wheels. No driveshaft needed.
Yes, we shouldn't need four wheel or front wheel drive at base where the ground will be level and free of obstructions.
Dook wrote:Why the pressurized cabin? Is it because you think the crew would be able to drive from one pressurized habitat to another using this rover? It seems you want multiple surface pressurized habitats. If so, why not just build them close together and have short hallways connecting them so no need to get in a rover and go through an airlock.
I think health and safety are paramount. While there are risks to having multiple habs with journeying between them, they should not affect more than a third of the people at a time. If you connect up all habs, a fire, explosion,pressure event or disease factor like mould could affect the whole settlement and, in the worst case scenario, kill off the whole community.
Dook wrote:If you wanted to drive the rover through an airlock door the door would have to be incredibly strong. Your habitat could never be pressurized to 14 lbs psi, even at 2 psi the force on the door would be 8,640 lbs.
I presume the pressure gradient can't be worse than in LEO, so something that strong. I am thinking of a narrow vehicle, more the width of a very large person than a big automobile.
Dook wrote:The cabin would have a battery operated heating system? Using electricity for heating uses a lot of watts. A small room heater uses 1,500 watts an hour but if you only want to use it for 5 min that would be fine. I don't think it would be needed since the vehicle would be left inside a warm pressurized habitat and driven for 5 min to another warm pressurized habitat.
Maybe a heater with a connected storage brick, so the heat can be stored (using "mains" electricity" while the vehicle is not in operation). Again my concern would be where an emergency situation resulted in the vehicle being stationary outside for something like an hour.
Dook wrote:You wanted radio controlled steering because you didn't know how to get the steering column through the pressurized cabin without there being a leak. There are seals that work.
My aim here was really to think of the simplest design so as to facilitate movement between habs, so as to simplify manufacture as far as possible. The aim is to have something that is 95% or higher by mass - maybe 98% - constructed from Mars ISRU resources. So that does suggest a keep it simple strategy. However, if a steering column with Mars-made seals is possible, then I have no problem with that.
It might be that there are simpler methods...perhaps we could have winch systems from one hab airlock to another. But I am not sure how the winch/airlock interface would work. Or if we can have effective seals, perhaps human cycle power would be better or something like those human powered rail maintenance platforms that travel the rails. Are there any ways you could impart human power to the wheels without a direct attachment from the cabin...maybe there is someway through a rocking motion with the crew pushing and pulling weights?
They only need to go about 1MPH for such a system to be effective - still only about 4-7min for 100-200 metre journeys.
You don't like the idea of connecting multiple habitats because of the risk of fire, explosion, or pressure event, or disease like mold? The risk of fire would be low, an electrical fire would probably be the only way that could happen since there would never be any flammable gasses inside the habitat. All electrical devices would have fuses that would prevent over voltages.
An explosion can only happen if you have flammable gasses. There won't be any.
A pressure event could happen if the habitat vacuum pump over pressurizes the habitat, the warning system somehow fails to warn the crew (because it's pressure switch fails) and the safety over pressure relief valve fails to open to release the building pressure. If that happened the pressure hatch seal would probably blow out and you would lose all pressure in a few minutes. In that case the crew would have to get to their Mars Suits immediately and fix the problem. It's possible but probably has a very low chance of happening because three things would have to fail, the pressure switch that controls the vacuum pump, a pressure relief valve, and the pressure warning switch. Pressure relief valves are simple, a valve with a spring that opens when the pressure gets over 5 psi. It's not likely to fail.
There could be a disease like mold? There isn't any mold on Mars. All the plants would be shipped as seeds but it's possible that some of the seeds could have mold on them. In that case those seeds would be thrown away, discarded outside on the surface.
The electric heater is just in case the small rover got stuck outside for an hour or so? In day time the temperature on Mars near the equator can reach 70 degrees. If there were driving at night and broke down, then they would be need the heater. No one should be outside the habitats or the Long Range Rover at night.
The seal for the steering column would be about a 1" wide circle. If you can't ship that small item to Mars then we can't go.
kbd512
I don't know where I want to store the Marscat's yet. They will probably be stored outside and connected to the base power to recharge every night. I would like to bring them inside the rover hangar but I don't like the idea of having to pressurize and depressurize the rover hangar each day to drive the Marscats out to do work. Also, the rover hangar would need a large door and if we pressurized the rover hangar to even 2 psi the force on the door would be incredible. I could just not pressurize the rover hangar at all and use it as a warmer place to store the Marscats while they recharge.
And I still need to figure out how long it takes to recharge the batteries over night and how much energy it will need. At night the RTG will be the only power source.
Those radiation heaters should be installed under all the batteries in the Marscats and the Long Range Rover.
I never planned on burying the tuna can. I would leave it on the surface as a backup habitat once the seven buried cylinder habitats are finished. The tuna can would have the rover hangar under it so burying it would be like building the pyramids in Egypt. Plus, the WAVAR unit in the rover hangar needs to have access to Mars atmosphere. Also, the tuna can would be very visible and seen from far away so the crew heading back to the base in the Long Range Rover could more easily identify where the base is.
Maybe make the WAVAR movable? Yeah, I actually had an idea for an aluminum zeolite cart that has a large intake filter, intake valve, intake fan, many zeolite panels surrounded by microwave screens with a magnetron and wave guide, then an exhaust fan, exhaust valve, and exhaust filter. The aluminum would heat up in the day and the microwave would be turned on so water vapor would fill the inside of the cart and a built in vacuum pump would collect and compress the water vapor into a removable tank that could be taken into the habitat. I still think I prefer having the WAVAR built in to the rover hangar inside wall.
Maybe pre-deliver the rover instead of having a rover hangar? The crew that arrives has to have it's own Long Range Rover because they will need a way to go and get stuff. You guys think that everything is going to land near the main base, they're not. Things are going to be landing all over the place. You're going to need a good sized rover that can go far out and pull a Mars Cart loaded down with heavy things (buried habitat components, greenhouses, food, water, supplies) back to the base.
One way to minimize the regolith moving would be to excavate a trough just deep enough to have half the cylinder sunk in place, then use the excavated "spoil" to recover it. That would cut the battery usage a lot. If we need more regolith, just dig up the surface and keep heaping it on until "enough" has been moved. That's how I was envisioning a "passageway" from the habitat units exteriors into the greenhouses would be built.
That's why I changed the depth from 17 feet to 12.
I could raise it further but the seven buried cylinders need 8 feet on top of them for radiation protection and I would like to put a 100 foot domed greenhouse over them to provide heat and I didn't want there to be a big hill inside the greenhouse.
A hill a few feet high would be fine but not too much.
The low level discharge is for storage and not use levels....when you discharge li-ion batteries that far you risk damaging the cell structure causing a barrier to charging to form which can cause the battery to short and not charge to full capacity. Recomended discharge in operation is only to 70% of its value before recharging....
http://www.techrepublic.com/blog/five-a … tery-life/
Characteristics of Rechargeable Batteries
Safe Lithium-ion Battery Designs for Use, Transportation and Second Use
I wasn't clear enough on the lithium-ion battery discharge, three hours of use (two 30 hp motors in each Marscat) would use 30% of the batteries (14 lithium-ion batteries). So, the batteries would be drained to 70% of their capacity.
Now, I have to figure out how long it would take to fully recharge the two Marscats from base power so they can be used the next day for 3 hours again.
I posted this under a thread which was really intended for larger more robust rovers, so thought I would start a new thread.
This is concerning a 98% Mars ISRU Rover design, specifically a design for a small one or two passenger Rover, to be used exclusively around the base on stone-free ground, for transport from one hab to another.
Having watched some You Tube vids of kids bulding Go Karts, I thought this would be well within the capacity of an early settlement.
I was thinking about it having the following features:
- Solid steel frame or steel tube frame. (Would steel tube allow for air heating?).
- Steel spring suspension.
- Chemical battery
- Electric motor
- Drive shaft
- Aluminium wheels or caterpillar tracks.
- Pressurised cabin constructed from honeycomb aluminium and with a basalt rockwool insulation layer (contained in a steel frame). Will have a single small air lock door.
- Cabin air supply system operating off gas cylinders. Good for 60 mins. Most journey times will be less than 5 mins (passengers will also carry emergency air supply on their person).
- Cabin would have its own battery operated heating system.
- No steering wheel column . Front wheel drive to be operated by radio control on a games console style device affixed to the inside of the cabin.
- Cabin to include either a narrow, thick pressure-proof windscreen with dust blowers to keep the windscreen clear, or to be driven by a camera/video screen system with no windows.
- Headlights operating off their own batteries. Brake lights not required. Only one vehicle will operate on the base for safety reasons.
- Max speed - 5MPH. No gears.
Some questions:
In what temperature range could such a vehicle operate? I'd like it to be able to operate in winter (during the lightest hours of the sol - not at night) as well as in summer.
Would caterpillar tracks work all right on Mars on fairly flat ground?
If the trips were kept to only 5 minutes the rover could have one lithium-ion battery.
The electric motor could be 10 hp and go to a golf cart type axle that powers both rear wheels. No driveshaft needed.
Why the pressurized cabin? Is it because you think the crew would be able to drive from one pressurized habitat to another using this rover? It seems you want multiple surface pressurized habitats. If so, why not just build them close together and have short hallways connecting them so no need to get in a rover and go through an airlock.
If you wanted to drive the rover through an airlock door the door would have to be incredibly strong. Your habitat could never be pressurized to 14 lbs psi, even at 2 psi the force on the door would be 8,640 lbs.
The cabin would have a battery operated heating system? Using electricity for heating uses a lot of watts. A small room heater uses 1,500 watts an hour but if you only want to use it for 5 min that would be fine. I don't think it would be needed since the vehicle would be left inside a warm pressurized habitat and driven for 5 min to another warm pressurized habitat.
You wanted radio controlled steering because you didn't know how to get the steering column through the pressurized cabin without there being a leak. There are seals that work.
What temperature range could such a vehicle operate? If you're just driving from a warm hab to another warm hab and spending only 5 min in the Martian cold there's no problem. The only cold problem you might have would be the battery freezing if you left it out.
Would caterpillar tracks work on Mars? Yes, but tracks use more energy than wheels. I think the wheels should just be shaped like the bracket symbol [ and 1.5 feet wide, maybe even 2 feet wide, so they don't sink in deep sand.
kbd512
I think I'm going to have to increase the number of batteries to 14 but lithium-ion is fine. I still like the idea of adding the electrolyte when they get to Mars. Even so, three hours of use would discharge each battery about 30%, which might be too much.
And if I only dig down 12 feet instead of 17 then I can cut the three Marscats down to only 2 and it would take 23 days, 3 hours of use a day, to dig out the area for the buried cylinder habitats.
You thought I wanted to stack zeolite panels up, in a grid arrangement? I did for the zeolite cart, not stack them up but put five or six in a row that a fan or two would blow the atmosphere through. For a built in WAVAR unit having panels in a row inside microwave screens would be okay as long as the air has to flow through them. I want the WAVAR unit to go in the Rover Hanger, probably built into the inside wall with an intake vent and an exhaust vent.
You're not sure how much noise would be transmitted through a vacuum? Yeah, don't know for sure, but not being able to get easy access to fix it is also a problem.
We could use a Ramgen? How much electricity would it use to spin it up and what kind of motor would spin it that high? Jet engines spin at 11,000 rpm.
SpaceNut
What did NASA or the US charge the Apollo astronauts? What did they charge the space shuttle astronauts? We don't do things in space to make money.
Elon Musk might, but that's his problem.
Dook,
MOXIE for CO2 Filtering:
You have to filter the CO2 out of the air. The amine swing bed (CAMRAS) does that.Spacecraft Complexity:
Apollo looked like Zvezda and so did the Space Shuttle. The fact that you haven't seen pictures of the wiring says nothing about what the internals of the vehicles actually looked like. I just looked at a picture of the wiring and piping in the LEM. Same thing. The LEM had core wire rope memory. The Space Shuttle contains 230 miles of wiring and is actually more complicated than Orion, which only has 20 miles of wiring. The Apollo spacecraft had 15 miles of wiring.
If the mini-Moxie converts CO2 to oxygen, why would I then have to filter the CO2 out of the air? I'm fine with still having two backup CAMRAS units and an emergency fan that blows cabin air through a CO2 absorbent but if the mini-Moxie can do it then you don't have to power up the CAMRAS constantly.
The Apollo capsule and the space shuttle looked like the ISS with cables sticking out all over the interior? No, they didn't.
Question: normally the mini-Moxie takes in Mars CO2 and converts it to oxygen and CO and discharges the CO overboard. Can the mini-Moxie take in habitat air and convert it to oxygen and discharge the CO?
It should be able to do that. If so, you don't need the CAMRAS unit to scrub CO2.
kbd512 post #265:
Rocket building and repair via the use of a 3 D printer is a leg up of commerce and export as well as for reuseability of rockets that once delivered cargo in a oneway mode to start a reuseable sycle once refueled. This is a step past exploration/science of the first few missions towards settlement or permanent presence and colonization in the future.
Dook post 267
This would lead to independance from the financial burden with an economy of retur for investment via exports of anything...kbd512 post #265:
The rovers did find sulfur sub serface as the wheels churned it up as it drove through that area.
I got thinking about the use for waste heat and was thinking of using it to create air flow via updraft chimney shape with the WAVAR at the top to capture the moisture. It does not need to go all that high it just needs to act like a large area tent to allow for volume of heat to be obsorb to be funneled to the peak of each direction of intent to make it go through the units....
Repairing rocket engines on Mars would lead to financial independence from the Earth? The best way to achieve financial independence is to provide for yourself. That means produce your own oxygen with plants, grow your own food with plants and chickens and tilapia fish, recycle your water, and maintain your shelter.
If they can do those things, what do they need from the Earth?
Those photos I posted of Zvezda's interior are what the inside of real tuna cans looks like, no matter who made it. There's more wiring, piping, and computer-controlled equipment than you can shake a stick at. Maybe there's a simpler way to do things, but every spacecraft I've ever seen looks like that. The engineers who design these things know what works and what doesn't. We've had decades of long duration space habitation. Certain things work well, others... not so much. Mostly, you'll find lots of redundancy. That's a good thing, because electrical and mechanical problems happen. Nothing as complicated as a spacecraft will ever be problem free, but if you have workable methods to resolve problems then it's not a death sentence for the crew.
Unlike what you see in Hollyweird movies, all airlocks are manually controlled with levers or cranks and designed in such a way that no human could actuate the airlock while it's pressurized. Docking and berthing locks are different. Those are electro-mechanical and also employ redundant systems.
Apollo didn't look like that, with cables crisscrossing all over the place. The space shuttle didn't look like that. I don't know why the ISS is like that but it doesn't give me confidence in the ability of aerospace engineers to design things.
If one wishes to see what robotics are capable of doing, then visit the BMW factory in Germany (Munich). The entire vehicle is robotically assembled with welds executed to a precision no human is capable of making. Everything is controlled by laser alignment. I had a tour of the factory 3 years ago while taking delivery of my new X-1. kbd512 is also correct in regard to soldering connections on circuit boards; it's simply on too tiny a scale for "soldering iron and solder" work by a human--unless the human does this type of work every day. Need a jeweler's loupe to work on such connections. Also: if we needed to bring along replacement circuit boards for all the controls and instrumentation of everything, we'd had literally hundreds--if not thousands of them. Instead we bring a 10% backup number of bare boards (at 10 % the weight penalty) and simply print as needed. Maybe this clarifies things as to weight penalties.
Robots can weld? What if the part that needs welding is in the parking lot. Can the robot go out there, look at it and weld it there? What if the material needed to be welded is aluminum, can the robot distinguish between steel and aluminum and change from MIG to a TIG welder? Robots can perform functions if everything is set up for them.
If we needed to bring along circuit boards for everything we would have to bring literally hundreds, if not thousands of them? My home computer has one motherboard. So, you're saying a mini-Moxie needs more than one computer to operate it? You're saying a WAVAR unit has more than one computer? You're saying the CAMRAS unit has more than one computer? They each have one electronics box. That's three motherboards, not thousands.
What is the difference in weight between the printing powder and the same component already pre-assembled?
kbd512
I didn't say that bearing grease deteriorates silicone, it deteriorates rubber.
We need an architect to tell us what we can get away with? Architects can design things but their ideas have to be checked by a qualified structural engineer.
See if I can solder a chip on a new computer board, it's all done with robots? Maybe I can't do it but the Voxel 8 can't do it either since it's just a sprayer but I guess a 3D printer with a real laser could.
Marscat could work but not with 4,900 lbs of batteries? Each Marscat would weigh 1,600 lbs and have 12 batteries. So, the batteries would weigh about 600 lbs. All of that is Earth weight.
What geometry would I like to use to get the zeolite panels into a smaller cavity for the microwave to irradiate? Think of a cereal box laid on it's side. All the sides would be zeolite panels. The top and bottom zeolite panels would be large rectangles, the sides all around would be much shorter, and the bottom would not have a zeolite panel but would fit onto a duct that would have a fan that would push Mars atmosphere through. The entire thing would be surrounded by microwave screens and have a wave guide going to it just like a home microwave. An exhaust fan would expel the Mars atmosphere from the microwave chamber out through a dust filter.
A couple of other things I don't like about the U of Wash. WAVAR is that it has a 6' fan built into the ceiling so it would be noisy as hell while the crew tried to sleep. And there would have to be a hole in the roof of the Mars Hab so this fan could expel Mars atmosphere but the roof has to be very strong because the entry parachutes have to attach there.
A compressor would work better than a fan to move Mars atmosphere? Compressors create a lot of heat. A normal jet engine heats the air up to about 600 degrees by the 5th stage.
I think your 8 feet of regolith shielding is excessive from everything I have read, especially as plants handle Mars level radiation v. well.
I agree with a high ceiling if we can manage it, because that enables more plant trays. Not sure why you want to build a complicated system why not build straight trenches out from a central habitat like a cross?
My real concern though is health and safety,as the more you attach in a pressurised environment to your central habitat, the greater the scope for disaster, specifically fire or a catastrophic pressure event - but also if we are talking about a farm hab environment, spread of mould or other pathogens.
Dook wrote:Marscat
My idea is to have seven 25' buried circular cylinder habitats each connected by a short 5' hallway with the living habitat at the center and six hydroponics and growing habitats around it.
The habitats would be 8 feet tall, have a 6" ceiling panel, and be buried under 8.2 feet of regolith so we would need to dig down 17 feet and level the bottom.
So, digging a circular pit 17' down and 85 feet wide at the bottom would require moving about 96,417 cubic feet of material. Tapering the sides to a 45 degree angle would require moving about another 43,350 cubic feet of material. So, that is a total of 139,767 cubic feet, if my math is correct.
A Marscat that is the same size as an Earth bobcat has a 5.6 foot wide by 2 foot deep bucket. So, that's about 11.2 cubic feet of material per load. If the Marscat can make 60 passes an hour, one a minute, it will move 2,016 cubic feet in three hours. Using three Marscats that would be 6,048 cubic feet moved a day.
It would take 23 days to dig out the pit before you could start to build the seven buried cylinder habitats.
The three Marscats (1,600 lbs each, total of 4,800 lbs) would be in the Rover Hanger along with a Long Range Rover (2,000 lbs) and a tracked Mars cart.
Using 8.2 feet of regolith for shielding is the number that other people came up with, not I.
Plants handle Mars radiation well? The shielding is for the people, not the plants.
Why build a complicated system instead of straight trenches? I didn't think that circles were complicated but the reason is to keep everything close together so we could then build a 100 foot wide dome greenhouse over the top of it to provide heat and possibly be able to pressurized the dome to grow plants.
The more you attach to your central habitat the greater the chance for fire or pressure failure or mold or other pathogens? The buried habitat will be pressurized, the pressure will equal the weight of the regolith on top but even if a pressure loss does happen the habitats will be strong enough to keep from collapsing.
The chance for fire is always present if you have electronics. The growing habitats will be very simple, hydroponics with LED lighting and plastic grow tubs and trays so they're not likely to catch fire. The central habitat will be like the Mars Hab but you will have 4 crew who live there to fight any fire.
About the spread of mold and other pathogens, if you don't bring any there won't be any.
I'm not saying you can't print silicone seals. I think trying to add an extremely thin layer of silicone, or other seal material, to a seal to resurface it is not worth the time or effort.
Even if you could do this, the center of the seal would still be hardened and would be prone to breaking. If it's an o-ring that is hardened from heat or brittle from cold, they usually break when you remove them because you have to stretch them to get them off a piston.
Seals should always be replaced. If you want to melt the old seals and recycle the material and use it to make new seals, that's okay.
Marscat
My idea is to have seven 25' buried circular cylinder habitats each connected by a short 5' hallway with the living habitat at the center and six hydroponics and growing habitats around it.
The habitats would be 8 feet tall, have a 6" ceiling panel, and be buried under 8.2 feet of regolith so we would need to dig down 17 feet and level the bottom.
So, digging a circular pit 17' down and 85 feet wide at the bottom would require moving about 96,417 cubic feet of material. Tapering the sides to a 45 degree angle would require moving about another 43,350 cubic feet of material. So, that is a total of 139,767 cubic feet, if my math is correct.
A Marscat that is the same size as an Earth bobcat has a 5.6 foot wide by 2 foot deep bucket. So, that's about 11.2 cubic feet of material per load. If the Marscat can make 60 passes an hour, one a minute, it will move 2,016 cubic feet in three hours. Using three Marscats that would be 6,048 cubic feet moved a day.
It would take 23 days to dig out the pit before you could start to build the seven buried cylinder habitats.
The three Marscats (1,600 lbs each, total of 4,800 lbs) would be in the Rover Hanger along with a Long Range Rover (2,000 lbs) and a tracked Mars cart.
kbd512
You want to repair rocket engines on Mars? I know.
If we reuse rocket engines on Mars it cuts the costs of a colony? I'm going to have to disagree. It cuts the costs of a plan that is even more expensive but it doesn't cut the costs of a plan that is more efficient.
With an efficient plan everything won't be used once and thrown away. It takes one rocket engine to send a Mars Hab and Rover Hanger to Mars, that same engine lands them.
Your plan only works if you have a habitat already built for the people to move into when they get there so the rocket can leave. And your plan requires delivery of large quantities of material or the collection of massive amounts of water to be changed into rocket fuel and massive amounts of regolith processing to get common elements and rare alloy elements. Your plan increases the risk to make money for a billionaire.
Everything is not thrown away with my plan. It's all used on Mars, except the rocket engines.
Is sea water is boiled do we get fresh water? You get hot fresh water vapor but yes.
It's easier to boil salt water in a near vacuum? It is. How are you going to collect the water vapor? With a WAVAR?
Let's figure out how to build a strong foundation for a domed greenhouse? I was thinking of digging out and area, 85' circle that is 17' down and has 45 degree tapered sides, building seven cylinder habitats, burying them in regolith, as we bury the habitats we install 11 foot tall upside down "T" foundation sections made of carbon composite with steel rebar built in every foot or so. The upside down "T" foundation sections would have regolith piled on them and they would be arranged in a circle, 314 foot circumference for a 100 foot wide dome. The top of the buried upside down "T" section would stick out of the ground a bit, and so would the steel rebar, so a polycarbonate greenhouse panel could be bolted to it. If the upside down "T" section base was four feet wide I think it would have 1.4 million pounds of regolith on it so it would exceed the 1.2 million pounds of uplifting force caused by pressurizing the greenhouse to 2 psi.
Robots just can't do enough complicated tasks yet.
Welding robots have been taught how to weld? They can't look at something and see where to weld or choose whether to use a rod, wire feed, or tig.
3D printers can weld up cracks? The 3D printer could have a pre-programmed welding mode. I don't know if they have that ability now or not. Someone would have to tell the 3D printer exactly where the crack was on it's AutoCAD file of the object and the 3D printer would spray material over it. I don't know if just doing that would work. Cracks in thin aluminum airframes or thin steel tanks are not welded, they're stop drilled and patched. Cracks in thick aluminum and thick steel can be welded but you have to get penetration completely through the object. Sometimes you have to cut out the crack completely then weld it up.
You want to have a set of tools to repair things, like replace a chip on a motherboard? A soldering iron would do it.
The seals on the ISS are silicone and maybe we could resurface them with a 3D printer? Yeah, some of those seals are huge. I didn't read the entire thing, it seems that silicone withstands radiation the best. I think trying to resurface a seal is going to be more trouble than it's worth. A large circular seal would have to be moved under the 3D printer perfectly to add material in exactly the right amounts. I think you might look to recycling the silicone in some kind of heater that melts it then use that material in the 3D printer to just make a whole new one. I don't know how a 3D printer would make a circular silicone seal that is 16 feet across though. The 3D printer would have to be on a circular track.
A 3D printer is a tool? It is. It can do some things but it's not a game changer like some people think.
You want to extend the life of seals with greases? Each seal type uses a different type of grease. Black synthetic rubber o-rings for hydraulic applications use hydraulic fluid, not grease. Grease deteriorates rubber. Brown o-rings for gas applications use a different type of grease, I can't remember what it is right now. Silicone seals, I don't know. Lubricating the seals usually helps them slip over a piston or whatever but doesn't really extend their life.
Complexity is allowable if it dramatically lowers the power requirements? Correct. Why would a WAVAR with zeolite panels fixed inside a microwave need more power to vent them?
Recycling water on the ISS is not enough probably because they're not getting all the water from feces waste. If the Mars base buried habitat has a solid waste settling tank the water would remain in the habitat.
You would rather have a robot collecting regolith around the base and have it dump regolith in a box? That's fine. I don't think it could operate 24/7, it would have to recharge some time.
You've never seen anyone using their golf cart for serious earth moving or long range transportation? When on Mars, do as the Martians do.
We already use machines to scan for cracks? You mean a non-destructive inspection machine? They don't work by themselves. Someone has to dip the material, magnetise it, then inspect it with a magnefying glass and look for cracks.
I'll address the Marscat digging in the next post. It's going to take more than one Marscat working more than one hour a day.
Dook wrote:If I don't know how to do anything I should stay out of the way? Oh, another internet control freak who gets upset when someone has different ideas. Let me give you some real advice old man, if you can't keep your cool on the internet, don't use your real name and don't publish that you can be found at monthly public meetings.
Is that a threat? You realize a skilled IT person can trace back your IP address.
Dook wrote:I don't need to know how to do anything when I can just pay people to do those things for me.
Mars doesn't have people you can hire for peanuts. You have to do everything yourself. If you can't, then you don't belong on Mars.
Dook wrote:I don't understand the basics? You mean like how to make swords on Mars? Those basics?
Do you know how to make a hammer? How to make a screwdriver? How to make any tools? When your fancy stuff with "Made in China" stamped on them break, what are you going to do? Send an email for a replacement? From China, while you're on Mars? When your life support equipment breaks, and spare parts are on order but will take 26 months to get there (or 17 years by your schedule) how long can you hold your breath?
Dook wrote:Your taxes fund the Canadian Space Agency? Wow. Thanks for the arm on the Space Shuttle. That was soooo incredibly important. You know that was just a nice little hand out to make you guys feel like you have a real space agency, right?
NASA wasn't able to design or build it. And you obviously forget, in 1961 NASA planned to land the Apollo CSM on the surface of the Moon. That's why the Service Module engine was so large. It was an engineer from Canada who proposed spitting it into Lunar Excursion Module (LEM) and Mothership (CSM). That same engineer designed the landing legs for the LM. After the Kennedy administration pressured Canada to cancel the Avro Arrow, NASA had first pick of Canada's best and brightest. A contractor in Quebec manufactured the feet for all Apollo LMs. I'm sure America would have eventually figured out how to go to the Moon without Canada, but it would have taken more time. But when the Soviet Union broke up, declassified documents from Russia stated they tested their LK in Earth orbit 3 times in 1972. They were ready to go to, but was cancelled by Russian politicians because Apollo 11 had already been them. So if Apollo 11 had been delayed due to Canada not helping, there's a good chance the Soviets would have gotten to the Moon first. Yes, the Russians were not working alone either. They had help from the rest of the Soviet Union, primarily Ukraine. But if Ukraine continued to help Russia with their space effort as much as they did, but America did not have help from Canada, then the Soviets would have gotten to the Moon first.
So stop dis'ing Canada!
Dook wrote:Canada built a wake observing satellite? We don't reveal our top secret satellite capability. It's okay that you guys up there "think" you invented it first. Why didn't you launch the satellite yourselves? Oh, you can't, that's why. But good job on the satellite anyway.
Continue to think that. Canada invented it. And Canada didn't even try to invent a wake observing satellite. Canadian scientists worked on a satellite to measure sea ice in Canada's arctic; to measure where it was safe for an icebreaker to sail, and where it wasn't. The "wake" thing was pointed out by the US military after they looked at our specifications.
Dook wrote:We don't owe you anything.
When I was a child, a representative from the Soviet Union came to my city with a working scale model of a Soyuz launch vehicle on its launch pad. He tried to get Canada to support the Soviet space program. Canada chose to support NASA instead. And you claim you owe Canada nothing? Canada's Avro Arrow was the most advanced fighter jet of its time, but the American administration put pressure on Canada to cancel it. Canada's pride was destroyed. And you claim America owes us nothing?
Dook wrote:This is not a US only issue. Your country is free to conduct it's own Mars mission any time it wants to. I think we will be waiting a long, long, long time for that to happen. Libya will probably make it to Mars before you do.
Canada partnered with Russia and Ukraine? Together we could achieve more than any one country in the world. Robert Zubrin proposed a Mars mission launched on Russia's Energia launch vehicle. You realize that could still happen.
A skilled IT person can trace IP addresses? Have fun with that. Make sure you bring your Uhlfberht sword.
Mars doesn't have people I can hire for peanuts, they have to do everything? No, they don't have to do everything. They have to maintain their life support equipment and grow food. Why would you think they would have to do everything?
Do I know how to make a hammer or a screwdriver? I don't have to know how to make them, I have plenty. A Mars colony will take some along.
When my fancy stuff that says made in China breaks what am I going to do? I buy another one. How would a Mars colony break a full metal hammer?
When life support equipment breaks what are they going to do for 26 months until a new one gets there? The crews main function is to survive, so, they will be trained on how to fix all the life support equipment and they will have at least two mini-Moxies and spares to repair both of them at least twice.
Name the life support equipment components that you can make with a small forge? An electric motor? Nope. A vacuum pump? Nope. Bearings? Nope. Filters? Nope. O-rings? Nope. P sensors? Nope. Magnetrons? Nope. Wave guides? Nope. An amine bed? Nope. A zeolite panel? Nope. A solar panel? Nope. An RTG? Nope. A reactor? Nope.
So, you want a forge so they can make a hammer on Mars when all they have to do is bring one.
NASA wasn't able to design or build the space shuttle arm? So, US companies designed and built the Apollo capsule and the space shuttle but we couldn't design and build a space arm that is so weak that is can't even lift itself on the Earth?
I should stop dis'ing Canada? I'm just defending myself. We don't have to agree. I'm okay with that. I don't run away from disagreement. This is complicated stuff and none of us knows everything.
Canada invented the wake observation satellite? Okay, fine.
Canada chose to support NASA instead? Did you give us money? What was the support?
Canada's Avro Arrow was the most advanced fighter jet of it's time and the US put pressure on Canada to cancel it? I looked it up, it seems that it probably was the most advanced fighter of the time but it was cancelled by Avro because they couldn't sell it to the US. Also, it seems the Avro company had a Russian agent working for them.
I've been all over the world, visited 14 different countries and most of them multiple times. Every country has people who blame the US for everything that ever happened or didn't happen to their people. Jealousy is a dangerous thing.
We don't owe you or anyone else a thing. NASA screwed up the 90 day report but that probably saved lives because some of the technology wasn't ready yet.
Canada could partner with Russia and Ukraine and go to Mars? I don't think Ukraine is going to partner with Russia on anything. But Canada could join up with Pavlovs dogs. See ya, wouldn't want to be ya.