DeGrasse Tyson's Mars challenge to Elon Musk

Dook · 2017-04-17 09:45:24

NASA thinks that they should maximize available resources? Using satellites and small rovers to study Mars is not preparing to maximize local resources.

Most other people interested in Mars colonization think we should use Mars resources? Because they don't like the idea of living in a tuna can for many years with others and not getting out and exploring Mars very often and never coming home. You can't get around your agenda. You think that colonists on Mars will somehow have it better than people on the Earth. It's more important to you than anything, to be able to imagine getting away from this dreary life and do something exceptional. People who want to escape the Earth won't get on a NASA mission. The might get on a SpaceX one though. I think Elon Musk counts on those types and that's a huge wild card.

Sending a Moxie to Mars is fine. It's not going to drive around, pick up dirt, bring the dirt back, process the dirt, and then throw most of it away.

There are glaciers of solid ice on Mars? Are they at the poles? If so, trying to use a manned rover to drive from your base just north of the equator to the poles and back for a few buckets of water doesn't really make sense. But we're going to wait for robots to do all of that for us, right? I'm okay with that. Let's wait.

Your agenda is preventing brain damage? So you're colonists are never going to leave the sulfacrete habitat?

So your sulfacrete home would have a 1 meter thick walls and roof for shielding? So, 3 feet of sulfacrete is better than 1 foot of water and 1 foot of sand? Then we can put two feet of sand on top of the tuna can, that's still quicker and easier than trying to process material so you can spray a small separate home.

Using resources to build structures means less stuff shipped from the Earth? But you said that for every home you would need to ship another pressure door, another oxygen monitoring system, a CO2 removal system, and a water recycle system. How is that less?

The homes can be built with robots? Sounds great, let's wait until that becomes possible. I'm very okay with reducing the risk to humans.

The size of the tuna can that's carrying people to Mars can be made smaller? Why would anyone want to do that? Oh, more people means more profit, right, profit is the goal.

If a colony on Mars can't grow enough food to sustain themselves then bringing them home would be the right thing, no matter how many homes they've built. In that case you would want to have to move as few people as possible, like 4, not 100,000 or 1 million.

How do I determine what's necessary? I use this formula X = the temperature on Wednesday in Palma De Mallorca.

You don't like paying for water when you are living on a giant ice cube? Figure out a better way then. So far, none of the water collection ideas is reasonable other than drilling a well inside the greenhouse and heating it to vent water vapor into your greenhouse, and that will probably get about one or two hundred gallons.

Maybe you could drill four wells at the corners of your greenhouse, but still inside, and then you would have four wells to get water vapor from? That would work. There would be a possibility that the ground beneath you might subside though.

So, urine kills now? You can look online and find stories of people drinking their own urine in survival situations. It didn't kill them.

The Moxie and RTG are so small and light that you can deliver all of them with a tuna can? You're talking about the 1% sized test Moxie. I'm talking about a full scale one. It's not going to be small at all.

The size greenhouse I can fit in a tuna can depends on what else I want to put in it? One launch would be entirely greenhouse panels and nothing else.

What do I consider completely full oxygen supplies? Both Moxies working well, the tuna can habitat has it's oxygen container full, the rover has all of it's oxygen bottles full, the extra oxygen bottle on the tuna can is full, and the small portable oxygen bottle is full as well. Food would be at least a years worth. Only then would I send tuna cans with just people but those tuna cans would have full oxygen tanks and a years supply of food and probably a few needed parts.

You're not saving money by making tuna cans smaller if you have to send extra pressure doors, oxygen monitors, and water systems to Mars.

Congress will simply give NASA more money if they ask for it? If lives depend on it, yes. But, I'm sure congress would also require NASA to come up with a solution as well, maybe bring them home. This is why you have to go slow.
Elon Musk has a picture of a composite LOX tank? Well, that's something. I have no doubt that he really wants to build the rocket.

Whether it works or not is a bit of a question, and whether he can get it to start bringing in money is another. NASA is slow because they are risk adverse, but they should be.

Peanut butter and jelly would work on Mars? I don't know. I haven't done much research about what plants would be best for Mars. Wild blackberry's are very drought tolerant (no water needed all summer), they can grow 6 feet a year, and produce lots of fruit but only once a year.

A fan won't pressurize the greenhouse? Yeah, I suspected that. We would have to rely on zeolite panels to outgas CO2 and water vapor inside the greenhouse. That would take some time.

I need sand around the sides of the tuna can as well? I guess you could move material up against the tuna can if you had to. In your idea you have to move a great deal of material anyway to process sulfur, why not just move it up against the tuna can, that way you wouldn't have to process it.

You would land the tuna can in a crater? The tuna can coming down just wouldn't be able to maneuver that much, if there was a crater close as you're coming down, maybe, but you'd have to hit it perfectly. Land on the side and you tip over.

Curiosity didn't take 30 years to design, build, and test? Nope, it didn't, but it doesn't do much. It certainly can't process material to get sulfur.

A foot of water in a sack in the walls of the tuna can would be way too heavy to get to Mars? Yeah, 53k is way too heavy. If everything you're saying is true, then no one can go to Mars until we have warp drive or some other radiation shielding. What is the ITS going to use for shielding?

Super heating the ice with a radioactive drill bit idea? Would the radioactive material cause the water vapor to be radioactive? Would the radioactivity interfere with the robots electronics?

The drill bit is powered by a super capacitor? Don't they release their electricity in seconds? That's not long enough to drill 33 feet. Would you have hundreds of super capacitors firing in sequence to do it? If you don't hit rock it would probably take about 30-45 min to go that deep.

Last edited by Dook (2017-04-17 09:47:13)

Dook · 2017-04-17 09:58:07

louis wrote:

Dook has become our resident Eeyore, which I think is nice. It's good to have a wall of negativity to bounce ideas off and to challenge any unwarranted optimism.
As indicated above, if Musk's plans mature then that is a complete game changer. You hardly need to make anything to begin with if you can send 10,000 tonnes of cargo every couple of years. Or rather, you can take the factory with you and assemble it on Mars.
However, more modest approaches do in my view require innovative ISRU. I believe it is possible. I haven't yet come across an industrial process that can't be replicated on a small scale. Mars has some special challenges that aren't found so much on Earth but I think it's good also to remind ourselves just how benign the environment is in many ways: no earthquakes, hurricanes, devastating tornadoes, huge floods, tsunamis or deluges of rain. Light winds and dust storms are about the worst of it. Temperature is a problem, but we've shown we can live comfortably in Antarctica all the year round. We've shown we can live in orbit for long periods (ISS). We've already landed humans on another celestial body.
The idea we can't easily locate water and generate oxygen I just don't accept. We have significant water signals for huge swathes of the planet. Electrolysis is a simple process. We collect the permafrost regolith and we melt out the water ice which is then put through a filter process. For producing hydrogen and oxygen, we put the water in large basin we construct on Mars (e.g. from formed basalt) and we do the electrolysis with equipment brought with us from Earth. We're supposed to get 8 kgs of oxygen and one of hydrogen for 50 KwHs. Compression will require more energy - but not huge amounts.

Ignoring the difficulties doesn't help. There are solutions, but some of them are not easy.

We absolutely can settle Mars but it has to be slow and well thought out.

We've shown that we can live in Antarctica all the year round? Do they grow their own food?

We can collect permafrost regolith? How?

We can melt permafrost to get water? To get water it has to be in a pressure environment. How are you going to do that?

We can then filter the water? Why? Why not just dump it on the plants?

We can put water into a large basin on Mars? Okay, if the basin is outside the water will just turn to vapor and float away because of the low atmospheric pressure.

Dook · 2017-04-17 10:15:40

Oldfart1939 wrote:

Louis-
I agree that water, once located, will not be as problematic as Eeyore has surmised. In another post on another thread, I suggested doing something similar to strip mining coal and hauling the still frozen blocks to a processing facility. This could be a giant plastic lined excavated "swimming pool," in a heated dome. It could have several Radioisotope decay heaters arranged to melt the "harvested product," but will require further processing to become usable for potable water. It could be used directly for electrolysis to H2 and O2.Eeyore has suggested that my proposed centrifuge isn't necessary, but it's way more effective than filtration. Filters clog and need cleaning or replacement; a basket centrifuge is simply cleaned using the built in "plow." Chances are, the water will be either alkaline or briney, requiring further treatment for agricultural and drinking. It could be used directly for some sanitation purposes, but mostly for subsequent electrolysis. I recall GW mentioning that blocks of Iron ore in the Mesabi range being about a "cubit" in size. Blocks of soil contaminated ice shouldn't begin to melt or sublime away during transport to the processing dome. All this drilling and melting to get the water sounds unnecessarily complex to me.

We could harvest ice blocks and bring them back to the greenhouse and let them melt inside the greenhouse? We can do that. No radioactive heaters needed, the greenhouse would warm up enough every day to melt ice easily. Any dirt in the ice would just settle.

If the ice has salt in it then I would use solar reflectors to boil it and release the pure water vapor into the greenhouse, then scrub the salt out with a scrub pad.

You will need a long range rover that has a towed cart and you will need to pick an area that is pretty much sand free and rock free unless you want to pull a heavy cart through sand and rocks for miles and miles.

The base will probably be located at 31 degrees from the equator, either north or south of the equator, since that is where Mars gets the most direct sun. And, you would want there to be large ice deposits nearby.

Here's the thing, your tuna can lander has recycled water and the greenhouse is completely enclosed so you shouldn't be losing very much water. What you want is to have constant flights back to the Earth, that's why they need to collect so much water.

If your rover breaks down when it's too far from the base or if it gets permanently stuck, the crew dies. To me, that's unreasonable risk just to send something back to the Earth.

They need enough water to grow plants and drink, that's all that matters.

kbd512 · 2017-04-17 10:38:47

Dook,

The colonist can spend about 10% of their time on the surface, so multiple the number of hours in a week by .1 and that's how long they can spend outside, long term, and stay under that 5rem/yr limit. The rest of the time needs to be spent in something with substantial shielding. No matter how you do it, the shielding is required for long term survival.

You don't have to drive very far to pick up sulfur. You can drive in circles and still get tons of the stuff. It's abundant. The fact that it's not 50% of what you'd pick up with every scoop of regolith doesn't change that.

The full size MOXIE was intended to make rocket fuel on Mars, which is something you said you weren't interested in. Humans require a far lower daily production rate, so a 2% scale unit (same as having 2 of the 1% scale demonstrator units) is sufficient for one person. If each MOXIE is designed to produce Oxygen for four people, it's an 8% scale unit. The 100% scale unit was for a LOX plant to make rocket fuel using water on Mars or Hydrogen brought from Earth.

The people who drank their own urine weren't doing it every day. You can ingest a little arsenic every day, but if you do it long enough, it'll injure or kill you.

That 1 foot of water was just for the top of the tuna can and doesn't include the sides. It'd weigh a whole lot more of the walls also contained a foot of water. Water is 8.34 pounds per gallon or 7.48 pounds per cubic foot. You can figure out how many cubic feet by looking up the volume of a cylinder (for a cylindrical water tank). Multiply that number by 7.48 and that's how much an area full of water would weigh at standard temperature and pressure.

The drill bit on the robot is tungsten carbide, so it's not going to make the water radioactive since very little radiation escapes. Tungsten is used to provide radiation shielding in nuclear reactors and it has an extremely high melting temperature, far above what the Plutonium can generate.

The super capacitors are designed to charge and discharge quickly, so yes, seconds to minutes of operation before the RTG's have to spend a minute or two recharging the super capacitors. Drill / recharge / drill / recharge, over and over again. If it takes several hours to go 33 feet instead of 30 minutes, will anyone care? Nobody who needs the water will be on Mars until after we get the water. If we have to drill several wells to get the water, then we have time to do that.

Dook · 2017-04-17 11:57:40

They can drive in expanding circles to get sulfur? They can. Then dump the material into the container on the nuclear power plant, and wait for it all to heat up.

How does the molten sulfur rise up over the other hot dirt? If it doesn't then you have to mix it up with something while someone else tries to catch the molten sulfur with a long laddle, but the sulfur would come out with clumps of regolith. So, you would have to do this many times, over and over again before you would get pure sulfur. This is unreasonable.

Sulfur is abundant on Mars? Yeah, just like oxygen is abundant on Mars if you ignore the fact that it's mostly bonded to iron.

The exploration crews would need full sized Moxies already on Mars making rocket fuel to get home but you're right, a settlement would not need as much. If they fit, the tuna can should have two built in Moxie units. That reduces my launch plan by four launches.

The people who drank urine didn't do it every day? No, they didn't but we have to realize that we are now drinking water that once went through a thousand insects, a person, some fish, and some dinosaurs. It can be cleaned, we just need filters and to boil it.

Too much water is too heavy to take? Yeah, that's probably why Zubrin had a small central area in his tuna can. NASA's Deep Space Habitat design has a water sack shield in it but I don't think the picture says how thick it is.

The super capacitor drill can take it's time charging and recharging? I just don't think the hollow drill going down into the ground will cause much water vapor to rise up other than extremely tiny amounts. If there was more atmospheric pressure then the hot water vapor would rise.

Oldfart1939 · 2017-04-17 13:07:36

Dook-

The reasoning you've applied about melting the ice blocks simply ignores the thermodynamics of the "system." In this case, the "system" is now the greenhouse filled with a big pile of ice blocks. Heat required to melt the ice has to come from somewhere and that means the atmosphere inside the structure. It has to be heated SOMEHOW or the ice will simply sit there in big chunks. Getting that heat from the internal greenhouse atmosphere will result in it becoming "cold as an icehouse" inside. Ice is undergoing a change of phase called melting, which is an endothermic process. That's why we'll need the radioisotope decay heaters. We're talking about melting TONS of ice to get adequate water supply and feedstock for electrolysis. Yes, settling can do part of it, but sedimentation, as it's called in the chemical process industry, is exceedingly slow and inefficient on the process scale of things. We need water for many uses, so speed things up we must!

louis · 2017-04-17 13:27:36

Food is grown in the Antarctica. I don't think farming is a top priority for Mission 1 but we'll want to at least make a start with salad vegetables and similar.

http://www.spaceref.com/news/viewpr.html?pid=13724

They grow 140 kgs of food per month in 200 sq metres at McMurdo base. Not bad.

Just take the frozen regolith, which could be put in plastic bags, to a pressurised hab heated to just over 0 degrees celsius and let it thaw out.

We dig out the frozen regolith with a specially adapted mini digger. It will incorporate a powerful microwave generator to loosen the soil.

It depends what we are going to use the water for. I presume that for electrolysis we want reasonably clean water.

Dook wrote:

Ignoring the difficulties doesn't help. There are solutions, but some of them are not easy.
We absolutely can settle Mars but it has to be slow and well thought out.
We've shown that we can live in Antarctica all the year round? Do they grow their own food?
We can collect permafrost regolith? How?
We can melt permafrost to get water? To get water it has to be in a pressure environment. How are you going to do that?
We can then filter the water? Why? Why not just dump it on the plants?
We can put water into a large basin on Mars? Okay, if the basin is outside the water will just turn to vapor and float away because of the low atmospheric pressure.

kbd512 · 2017-04-17 14:04:10

How can we obtain Sulfur?

* Frasch Process

* Production_of_Elemental_Sulphur_from_SO2.pdf

Dook · 2017-04-17 14:40:35

Oldfart1939 wrote:

Dook-
The reasoning you've applied about melting the ice blocks simply ignores the thermodynamics of the "system." In this case, the "system" is now the greenhouse filled with a big pile of ice blocks. Heat required to melt the ice has to come from somewhere and that means the atmosphere inside the structure. It has to be heated SOMEHOW or the ice will simply sit there in big chunks. Getting that heat from the internal greenhouse atmosphere will result in it becoming "cold as an icehouse" inside. Ice is undergoing a change of phase called melting, which is an endothermic process. That's why we'll need the radioisotope decay heaters. We're talking about melting TONS of ice to get adequate water supply and feedstock for electrolysis. Yes, settling can do part of it, but sedimentation, as it's called in the chemical process industry, is exceedingly slow and inefficient on the process scale of things. We need water for many uses, so speed things up we must!

The greenhouse would be pressurized to about 5 psi so the CO2 inside would be warm and it would convey heat to anything under the greenhouse panels, including feet of regolith on the floor. And object brought inside would warm up.

Bringing blocks of ice inside the greenhouse would cause it to become cold as an icehouse inside? No, it wouldn't. That's like saying that putting some ice into your drink and bringing it into the living room would freeze the living room. And, if we were somehow moving extremely large blocks of ice, which we won't be because they will be way too heavy, we would simply use solar reflectors outside the greenhouse to shine sunlight into the greenhouse to melt the ice blocks. Can we get back to reality?

You're talking about melting tons of ice? Not tons a day. Maybe a ton every two or three weeks if your ice deposit is close by.

You want to speed things up? Then you need multiple long range rovers going out and bringing back ice every day. OR you could have a moveable greenhouse, or an inflatable one. Or you could use a Zubrin mobile microwave truck to heat the ground and collect the water vapor but still the problem is how to get the water vapor to move into your container. You can't use a vacuum because it won't work on Mars.

Dook · 2017-04-17 14:48:26

louis wrote:

Food is grown in the Antarctica. I don't think farming is a top priority for Mission 1 but we'll want to at least make a start with salad vegetables and similar.
http://www.spaceref.com/news/viewpr.html?pid=13724
They grow 140 kgs of food per month in 200 sq metres at McMurdo base. Not bad.
Just take the frozen regolith, which could be put in plastic bags, to a pressurised hab heated to just over 0 degrees celsius and let it thaw out.
We dig out the frozen regolith with a specially adapted mini digger. It will incorporate a powerful microwave generator to loosen the soil.
It depends what we are going to use the water for. I presume that for electrolysis we want reasonably clean water.

They grow food in Antarctica? Okay, I'll take your word for it.

We could just bring the ice inside the pressurized rover and warm it there in buckets? We could but how much do you think the rover will be able to carry? Also, that ice would be mixed with some regolith so you would get dirty water. There is likely dry ice, frozen CO2, mixed in with the frozen water too so you would be contaminating your rover's air with CO2. And, every time you leave the rover you lose some pressure and oxygen.

The rover's pressurization would come entirely from it's on board oxygen containers, so, you can only go outside so many times before you deplete all the pressure and use up all your carried oxygen.

If your rover breaks down or gets stuck while it's away from the base. The crew dies.

There are no easy ways to get lots of water on Mars. It's just not worth it.

Dook · 2017-04-17 15:16:21

kbd512 wrote:

How can we obtain Sulfur?
* Frasch Process
* Production_of_Elemental_Sulphur_from_SO2.pdf

The link you provided explained how sulfur is processed on the Earth. They're using 650 to 1,000 C temperatures. Melting sulfur at 239 degrees F is one thing, taking it to 650 C is a completely different animal.

And that's not taking into account the other hydrocarbons needed to purify sulfur.

Last edited by Dook (2017-04-17 15:16:50)

Oldfart1939 · 2017-04-17 15:27:02

Dook wrote:

We could just bring the ice inside the pressurized rover and warm it there in buckets? We could but how much do you think the rover will be able to carry? Also, that ice would be mixed with some regolith so you would get dirty water.

Dook, have you taken Physics? What you're suggesting is not going to happen without some source of heating.

The phase change going for ice at 273 degrees K to liquid water at 273 degrees K requires an input of 550 calories per kg. You mentioned "warming it up inside the rover," so that means you at least understand that there needs to be a net heat input in order to accomplish that task.

My plan would be to have some very large plastic containers for this mined ice. (and have a heat probe immersed--isotope decay) to melt the ice. The atmospheric pressure certainly needs to be substantial or it will undergo another phase change and evaporate.

Dook · 2017-04-17 15:31:57

Since you guys have to have homes on Mars, here's a way to do it somewhat efficiently, bricks. But the bricks are made inside the greenhouse so that all the water used is retained. You need a pressure environment to have water on Mars anyway. The bricks would be fired inside the greenhouse too so all the water used to make them is kept. The mortar would be wet Mars dirt and you would use solar reflectors to dry it.

So, you can build whatever you want out of bricks as long as it's inside the greenhouse.

Dook · 2017-04-17 15:36:10

Oldfart1939 wrote:

Dook wrote:
We could just bring the ice inside the pressurized rover and warm it there in buckets? We could but how much do you think the rover will be able to carry? Also, that ice would be mixed with some regolith so you would get dirty water.
Dook, have you taken Physics? What you're suggesting is not going to happen without some source of heating.
The phase change going for ice at 273 degrees K to liquid water at 273 degrees K requires an input of 550 calories per kg. You mentioned "warming it up inside the rover," so that means you at least understand that there needs to be a net heat input in order to accomplish that task.
My plan would be to have some very large plastic containers for this mined ice. (and have a heat probe immersed--isotope decay) to melt the ice. The atmospheric pressure certainly needs to be substantial or it will undergo another phase change and evaporate.

The heating of the block ice comes from the CO2 atmosphere inside the greenhouse. Just like the heat in your house comes from the warm air inside the house. Or heating the ice can come from the pressurized and oxygenated atmosphere inside the rover but there we're only talking about a few buckets of ice.

Let's get back to reality please and stop with these games.

RobertDyck · 2017-04-17 16:30:37

Dook wrote:

Ignoring the difficulties doesn't help. There are solutions, but some of them are not easy.

The only way to solve any problem is start with the assumption it can be solved. Then do the work. If you're going to just stamp your feet, hold your breath, complain that it's too hard, then nothing will get done.

Dook wrote:

We absolutely can settle Mars but it has to be slow and well thought out.

It would have been slow starting in 1965, or 1968, or 1970. A film I saw in 1968, produced by NASA earlier that same year, is now available on YouTube. That film describes the NERVA engine, and promised a stage using that engine to replace the third stage of Saturn V. That film claimed it would be used to send a human mission to Mars, and promised the first human mission would depart Earth for Mars in 1978. That would have been exactly 10 years later. They did Apollo in less than 10 years starting from nothing, so using Apollo hardware it seemed reasonable for 10 more years for Mars. In 1970 they announced the PICA heat shield; the version at that time was 3 times the mass of the AVCOAT heat shield that protected Apollo when returning from the Moon, but with it an Apollo Command Module could return from Mars the same way. At that time they said a human mission would launch in 1981, the next launch opportunity. Then they said 1983. Then they said they'll get back to us when they figure it out. Then nothing until George H. W. Bush made his announcement in 1989 that lead to the 90-Day-Report. That died quickly, then Martin-Marietta had their engineers design a practical plan. Robert Zubrin and his partner David Baker were among them; they came up with Mars Direct, presented to NASA in June 1990. They could have gotten humans to Mars by 1999. Probably an unmanned test of equipment in 1997. But it didn't happen. Now we're still here debating. No real progress. SLOW MY ASS! This is not even slow, it's stop!

Dook wrote:

We've shown that we can live in Antarctica all the year round? Do they grow their own food?

They do have a greenhouse. Not large enough to provide all food, but they can fly in. During the worst weather, a Canadian twin otter aircraft can fly into McMurdo. During good weather, larger aircraft such as Hercules cargo plane can fly in. Mars requires a huge rocket to send a tiny vehicle. A tiny Dragon capsule requires Falcon Heavy. NASA and ULA built SLS. You keep going on about tuna can landers, you realize that would require either SLS block 2 or at minimum SLS block 2B. Do you know how much that will cost? A lot more than chartering a Hercules for one flight.

Dook wrote:

We can collect permafrost regolith? How?

Cold Regions Research and Engineering Laboratory - Permafrost Tunnel Research Facility

Dook wrote:

We can melt permafrost to get water? To get water it has to be in a pressure environment. How are you going to do that?

Two ways:

use a jack hammer to break out chunks, bring inside to melt
melt outside

Remember pressure on Mars is sufficient for liquid water. Temperature range between freezing and melting is narrow, but it does exist. Long duration would require covering the pool so it doesn't freeze at night, and so it doesn't evaporate. Also realize Mars permafrost has salt. Samples so far indicate all Mars surface soil has a lot of salt. That both drops freezing temperature, and raises boiling temperature, so it extends the temperature range at both ends. But it means melt water will be muddy and salty.

Dook wrote:

We can then filter the water? Why? Why not just dump it on the plants?

Salt, pechlorate.

Dook wrote:

We can put water into a large basin on Mars? Okay, if the basin is outside the water will just turn to vapor and float away because of the low atmospheric pressure.

Not if it's covered.

louis · 2017-04-17 17:07:07

We can melt the ice in an industrial hab where we will have lots of other machines working that contribute to the temperature. Habs can be highly insulated with aerogel. This is a non-issue.

Dook wrote:

Oldfart1939 wrote:
Dook wrote:
We could just bring the ice inside the pressurized rover and warm it there in buckets? We could but how much do you think the rover will be able to carry? Also, that ice would be mixed with some regolith so you would get dirty water.
Dook, have you taken Physics? What you're suggesting is not going to happen without some source of heating.
The phase change going for ice at 273 degrees K to liquid water at 273 degrees K requires an input of 550 calories per kg. You mentioned "warming it up inside the rover," so that means you at least understand that there needs to be a net heat input in order to accomplish that task.
My plan would be to have some very large plastic containers for this mined ice. (and have a heat probe immersed--isotope decay) to melt the ice. The atmospheric pressure certainly needs to be substantial or it will undergo another phase change and evaporate.
The heating of the block ice comes from the CO2 atmosphere inside the greenhouse. Just like the heat in your house comes from the warm air inside the house. Or heating the ice can come from the pressurized and oxygenated atmosphere inside the rover but there we're only talking about a few buckets of ice.
Let's get back to reality please and stop with these games.

louis · 2017-04-17 17:19:02

Robert - Good points.

Problem solving requires focus and drive. We know that these problems are not requiring any kind of huge technological leap - they are problems that just need to be addressed energetically and pragmatically, with proper resource funding.

NASA gave up on humans exploring space I guess around the time they realised that the Space Shuttle had taken them down a blind alley. Very sad. There is no doubt we could have got to Mars decades ago, had the organisational will been there. NASA can no longer provide the necessary funding. Their budgets are set in concrete, they won't make the allocations necessary, instead preferring to pursue a 100 goals.

Dook · 2017-04-17 20:08:38

SpaceNut: Can you fix my login. It's only letting me access the day old website, not showing new posts.

When I login it takes me to an old page but does allow me to post.

Last edited by Dook (2017-04-17 20:29:23)

Dook · 2017-04-17 20:35:26

RobertDyck wrote:

Dook wrote:
Ignoring the difficulties doesn't help. There are solutions, but some of them are not easy.
The only way to solve any problem is start with the assumption it can be solved. Then do the work. If you're going to just stamp your feet, hold your breath, complain that it's too hard, then nothing will get done.
Dook wrote:
We absolutely can settle Mars but it has to be slow and well thought out.
It would have been slow starting in 1965, or 1968, or 1970. A film I saw in 1968, produced by NASA earlier that same year, is now available on YouTube. That film describes the NERVA engine, and promised a stage using that engine to replace the third stage of Saturn V. That film claimed it would be used to send a human mission to Mars, and promised the first human mission would depart Earth for Mars in 1978. That would have been exactly 10 years later. They did Apollo in less than 10 years starting from nothing, so using Apollo hardware it seemed reasonable for 10 more years for Mars. In 1970 they announced the PICA heat shield; the version at that time was 3 times the mass of the AVCOAT heat shield that protected Apollo when returning from the Moon, but with it an Apollo Command Module could return from Mars the same way. At that time they said a human mission would launch in 1981, the next launch opportunity. Then they said 1983. Then they said they'll get back to us when they figure it out. Then nothing until George H. W. Bush made his announcement in 1989 that lead to the 90-Day-Report. That died quickly, then Martin-Marietta had their engineers design a practical plan. Robert Zubrin and his partner David Baker were among them; they came up with Mars Direct, presented to NASA in June 1990. They could have gotten humans to Mars by 1999. Probably an unmanned test of equipment in 1997. But it didn't happen. Now we're still here debating. No real progress. SLOW MY ASS! This is not even slow, it's stop!
Dook wrote:
We've shown that we can live in Antarctica all the year round? Do they grow their own food?
They do have a greenhouse. Not large enough to provide all food, but they can fly in. During the worst weather, a Canadian twin otter aircraft can fly into McMurdo. During good weather, larger aircraft such as Hercules cargo plane can fly in. Mars requires a huge rocket to send a tiny vehicle. A tiny Dragon capsule requires Falcon Heavy. NASA and ULA built SLS. You keep going on about tuna can landers, you realize that would require either SLS block 2 or at minimum SLS block 2B. Do you know how much that will cost? A lot more than chartering a Hercules for one flight.
Dook wrote:
We can collect permafrost regolith? How?
Cold Regions Research and Engineering Laboratory - Permafrost Tunnel Research Facility
http://permafrosttunnel.crrel.usace.army.mil/images/hometunnel.jpg
Dook wrote:
We can melt permafrost to get water? To get water it has to be in a pressure environment. How are you going to do that?
Two ways:
use a jack hammer to break out chunks, bring inside to melt
melt outside
Remember pressure on Mars is sufficient for liquid water. Temperature range between freezing and melting is narrow, but it does exist. Long duration would require covering the pool so it doesn't freeze at night, and so it doesn't evaporate. Also realize Mars permafrost has salt. Samples so far indicate all Mars surface soil has a lot of salt. That both drops freezing temperature, and raises boiling temperature, so it extends the temperature range at both ends. But it means melt water will be muddy and salty.
Dook wrote:
We can then filter the water? Why? Why not just dump it on the plants?
Salt, pechlorate.
Dook wrote:
We can put water into a large basin on Mars? Okay, if the basin is outside the water will just turn to vapor and float away because of the low atmospheric pressure.
Not if it's covered.

It's not stop. It's slow but not at a stop. We have rovers and satellites at Mars. We are learning a great deal about the planet without risking lives. Why the perceived sense of urgency? Because you want to see it happen while you are still alive. I'm sorry, that's just not a good enough reason to risk other people's lives.

I keep going on about the tuna can? I do. How else are you going to get there? In a Red Dragon?

If it takes the SLS block 2 then it takes the SLS block 2.

The permafrost research facility link you posted, I assume that some type of coal digging equipment was used to make the tunnel. So, you want to transport a coal digging machine to Mars on a Red Dragon?

We can use a jack hammer to break out chunks? How is the jack hammer powered? Are you doing this at the base to use it's power?

You say that we can melt ice outside on Mars? The pressure on Mars is sufficient for water to exist but only between the temperatures 33 to 35 degrees. That's probably about a two minute window before it turns to gas.

Covering a pool at night so it doesn't freeze isn't going to work. First, there won't be any pools. The water will either be frozen, as water for a few minutes in day time, or completely evaporate. Covering water won't hold in pressure, there isn't any pressure on Mars to hold in. And even if there was a pool the temperatures get down to -140 at night. It's going to freeze completely solid. Rivers in northern Alaska freeze a couple of feet and the coldest temperatures are only about -80.

We can't just use Mars water on plants because it has salt in it? Yeah, it probably does so we would have to use a solar cooker to boil it and release the water vapor inside our greenhouse. Then scrape the salt out of the can and dispose of it outside.

RobertDyck · 2017-04-18 00:07:54

Most of the work I do is in Celsius, not Fahrenheit. I have converted a few times to Fahrenheit, but let's stick to metric. Mars Climate Orbiter failed due to a metric-to-US-measure conversion error. Mars south pole gets down to -140°C in southern winter. Solution: don't go there. Human missions will go to a tropical latitude. That means near the equator, or within or at least near the tropics. The tropics are lines of latitude that equal axial tilt. Axial tilt on Earth is 23.45° so the tropics are north/south 23.45°. Mars axial tilt is 25.19°, so it's tropics are north/south 25.19°. That's where we want to go. (Not Kokomo.) Temperatures can range from +27°C to -111°C. The coldest temperature recorded by Viking 2 lander over more than a Martian year was -111°C. Mars pathfinder recorded -8°C to -77°C. Weather recorded by Curiosity last Saturday: air varied from -4°C during the day to -77°C at night, ground temperature +4°C to -104°C, pressure mean 831 Pa (0.831 kPa = 8.31 mbar). Air pressure from sols 9.5 to 13 varied from 691 to 780 Pa.

Mars air is so thin that it will not transport much heat. There is very little heat loss to the atmosphere. Most heat loss will be either radiative, or to the ground. Currently NASA uses spectrally selective coatings on windows of spacecraft, space station, and even spacesuit helmet visors. The spectrally selective coating is vacuum deposited layers of gold, nickel, and silver oxide. Only silver is oxidised. The purpose is to block UV, and control IR. They found Mercury astronauts developed cataracts later in life. The metal coating on plastic blocks 98% of UV, on glass the combination of glass and the coating blocks 99% of UV. There are UV absorbers that can be added to block even more. This is necessary to reduce the risk of cataracts. But the coating also reflects IR. It can reflect more long-wave IR from warm things like the ground, furniture, walls, etc., and less short-wave IR from extremely hot things like the Sun. That allows more heat from the Sun to get in, while trapping in radiant heat from the inside. That causes a net warming effect. By the way, this has already been commercialized. Two brand names: "Heat Mirror" and "Low-e" both use silver oxide. Commercial buildings on Earth don't use gold or nickel because they're not worried about UV, just IR. And you can tailor it to reflect more short-wave and less long-wave for a net cooling effect. In northern states and Canada, they use window coatings to warm buildings. In southern states they coat windows for net cooling. On Mars we definitely want net warming.
Space Radiation and Cataracts in Astronauts

But for an outdoors melting pool, you would use aluminized Mylar blanket to reflect all IR back in. Perhaps with bubble wrap for additional insulation. It will take a lot of heat to melt the ground sufficiently to melt permafrost. Once the ground is heated, you would want to keep it warm. Never let it cool, because that would waste heat. Just keep it warm to melt more and more water. I was thinking of breaking out chunks and bring it inside to melt. The guys at Mars Homestead suggested building next to a glacier or frozen lake, and melting a pool within it. Leave the surface ice as insulation. That's a good idea. Mars Reconnaissance Orbiter found glaciers in the sides of valleys at mid-latitude.
NASA: Glacial Ice Deposits in Mid-Latitudes of Mars

And I already posted about the frozen pack ice at Elysium Planitia.

One reason to cover the pool is to prevent evaporation. All water vapour would be trapped within the enclosed volume. Melting an outdoor non-pressurized pool on Mars will take significant heat. The Mars Homestead guys suggested using heat from one of the nuclear reactors. Water from the liquid water pool can be sucked up by a hose, with just a water pump. Some of the water would circulate through a heat exchanger in the nuclear reactor, return to the pool as hot water.

Don't boil water to desalinate. Instead use a reverse osmosis membrane. That requires significant water pressure, but a pump to produce that pressure requires less energy than boiling. Of course Mars Homestead was about settlement, not a science mission. Different scale. That project intended 3 nuclear reactors, each delivered with it's own cargo lander, carrying nothing but the reactor.

How would you collect ice on a science mission? An industrial hot-knife? That would work with ice, but permafrost would have too much mud, sand and gravel.

kbd512 · 2017-04-18 01:02:20

Dook wrote:

kbd512 wrote:
How can we obtain Sulfur?
* Frasch Process
* Production_of_Elemental_Sulphur_from_SO2.pdf

The link you provided explained how sulfur is processed on the Earth. They're using 650 to 1,000 C temperatures. Melting sulfur at 239 degrees F is one thing, taking it to 650 C is a completely different animal.
And that's not taking into account the other hydrocarbons needed to purify sulfur.

I think we'd use the Frasch process since the tracks of one of the MER rovers literally left a white and yellow trail behind it. The Frasch process only requires superheated steam and yields high purity Sulfur. The water robots can collect water required.

With respect to the chemical reactions required to yield Sulfur from Sulfur bearing compounds, SAFE-400's coolant loop has an outlet temperature of around 926C and we would need the heat and electrical power that a fission reactor delivers. Regarding the hydrocarbons, I believe CH4 was used.

The Mars Direct LOX/LCH4 plant made LOX and LCH4 using Hydrogen shipped from Earth in a Sabatier reactor. If return to Earth is not in the cards for the Mars colonists, then a Sabatier reactor could be repurposed to make CH4 to produce Sulfur. The water robots can supply the water, the systems already aboard ISS electrolyze water to make Oxygen and vent the Hydrogen to space. Instead of venting the Hydrogen, we could feed it to a Sabatier reactor. ISS already has OGS (to produce oxygen from water electrolysis) and a Sabatier reactor aboard, so no hardware development is required. Even if the MOXIE experiment fails (unlikely), as long as we can get water from glaciers on Mars there will be no shortage of Oxygen or Methane to produce Sulfur. If MOXIE is successful, then it's a second level dissimilar backup system to OGS.

Dook · 2017-04-18 10:16:02

RobertDyck wrote:

Most of the work I do is in Celsius, not Fahrenheit. I have converted a few times to Fahrenheit, but let's stick to metric. Mars Climate Orbiter failed due to a metric-to-US-measure conversion error. Mars south pole gets down to -140°C in southern winter. Solution: don't go there. Human missions will go to a tropical latitude. That means near the equator, or within or at least near the tropics. The tropics are lines of latitude that equal axial tilt. Axial tilt on Earth is 23.45° so the tropics are north/south 23.45°. Mars axial tilt is 25.19°, so it's tropics are north/south 25.19°. That's where we want to go. (Not Kokomo.) Temperatures can range from +27°C to -111°C. The coldest temperature recorded by Viking 2 lander over more than a Martian year was -111°C. Mars pathfinder recorded -8°C to -77°C. Weather recorded by Curiosity last Saturday: air varied from -4°C during the day to -77°C at night, ground temperature +4°C to -104°C, pressure mean 831 Pa (0.831 kPa = 8.31 mbar). Air pressure from sols 9.5 to 13 varied from 691 to 780 Pa.

For an outdoors melting pool you would use aluminized mylar blanket to reflect IR back in to hold in heat over night?
Once the water forms at 33 degrees F you would have to cover it to prevent it from getting any warmer because once it gets to about 36 degrees it turns to gas. There's just no way. It's not just about keeping in heat but keeping it between 33 and 35 degrees.

It would be better to just drop a towel into the water and soak it up then bring it back to your greenhouse before it gets too warm outside but even doing that is getting you extremely small amounts.

There is another idea from Mars Homestead about finding an ice lake and melting a pool under the ice? Once again, you need pressure it to keep the water as water. The ice you melt in the ice lake would turn to gas. There is no way around it. You have to pressurize it.

All water vapor would be trapped under the blanket? Okay, maybe you could do this over a small crater and there would be some water vapor under the blanket but you can't suck it up with a hose because there is almost no atmospheric pressure on Mars so a vacuum won't work outside. Still, you could lay out towels into the crater each day when the temperature gets to about 31 degrees outside, wait a few minutes, some water will form and run onto the towels, then put the towels inside some container and bring them into your greenhouse. This would only get you a cup or two of dirty water each day and only if the crater was near the greenhouse.

Last edited by Dook (2017-04-18 10:16:25)

Dook · 2017-04-18 10:28:36

kbd512 wrote:

Dook wrote:
kbd512 wrote:
How can we obtain Sulfur?
* Frasch Process
* Production_of_Elemental_Sulphur_from_SO2.pdf

The link you provided explained how sulfur is processed on the Earth. They're using 650 to 1,000 C temperatures. Melting sulfur at 239 degrees F is one thing, taking it to 650 C is a completely different animal.
And that's not taking into account the other hydrocarbons needed to purify sulfur.
I think we'd use the Frasch process since the tracks of one of the MER rovers literally left a white and yellow trail behind it. The Frasch process only requires superheated steam and yields high purity Sulfur. The water robots can collect water required.
With respect to the chemical reactions required to yield Sulfur from Sulfur bearing compounds, SAFE-400's coolant loop has an outlet temperature of around 926C and we would need the heat and electrical power that a fission reactor delivers. Regarding the hydrocarbons, I believe CH4 was used.
The Mars Direct LOX/LCH4 plant made LOX and LCH4 using Hydrogen shipped from Earth in a Sabatier reactor. If return to Earth is not in the cards for the Mars colonists, then a Sabatier reactor could be repurposed to make CH4 to produce Sulfur. The water robots can supply the water, the systems already aboard ISS electrolyze water to make Oxygen and vent the Hydrogen to space. Instead of venting the Hydrogen, we could feed it to a Sabatier reactor. ISS already has OGS (to produce oxygen from water electrolysis) and a Sabatier reactor aboard, so no hardware development is required. Even if the MOXIE experiment fails (unlikely), as long as we can get water from glaciers on Mars there will be no shortage of Oxygen or Methane to produce Sulfur. If MOXIE is successful, then it's a second level dissimilar backup system to OGS.

Okay, so we spend months getting all this sulfur and spraying a home and installing all the equipment. You would then leave the tuna can for the Mars habitat? Even if you would, that's not increased colonization. That's a lateral movement. The Mars population level stays exactly the same. Even if the settlers build 100 homes. How are you going to get 100 people to Mars without sending them there in a habitat?

Oh, the ITS, right? You they're going to sleep in bags fixed to the walls and not have a living space of their own.

Where is the extra food going to come from? Don't you kind of need more greenhouses already growing plants before the people arrive? How does sulfacrete hold up as a greenhouse? Does the sulfacrete absorb moisture and soften in a humid environment? I bet it would.

RobertDyck · 2017-04-18 11:47:49

Dook: With the Mars Homestead Project, I expected to cut large blocks of ice, bring them inside a pressurized environment to melt. But the other guys expected to melt water from an underground ice deposit, glacier or frozen lake. Their idea was do not expose the surface of the melt pool, instead excavate an ice cave. So the ice itself forms the roof to contain wave vapour. Just throw a hose into the pool, pump it up. A lot simpler if it would work. The team broke up, some left to form a corporation called 4Frontiers. Bruce was my friend, the one who recommended me, the project was founded by Bruce and Mark, but they left Bruce out of their new corporation. Project manager Mark Homnick wanted to melt underground ice. And a nuclear engineering master student at MIT, Joseph Palaia; was asked to design the reactor. He also wanted to melt in place. They believed the ice roof of the ice cave would condense any water vapour, drip back into the pool. They dismissed my concerns about boiling off when NASA discovered evidence of rivulets running down the side of gullies. My idea of aluminized mylar with "bubble wrap" insulation is just for the hole in the ice where the hoses enter the ice cave. One hose to suck up melt water, another to provide hot water to melt the ice.

You're arguing over something that wasn't my idea. The project manager Mark was insistent on this, and I had other more important arguments, so I just accepted it. I was asked to design life support, and I argued for an ambient light greenhouse because it was the only life support that would work during complete power loss. So I chose my battles; accepted Mark and Joe's idea.

By the way, I've linked images of the "Hill Side Settlement" from the website of the Mars Foundation. I could link a video of the same settlement from the website of 4Frontiers Corporation. We came up with the "Hill Side Settlement" before the split.

So do you want to run detailed numbers? You will have to start by choosing a specific site. What is the exact pressure at that site? What is the ice resource? How much salt in the ice? For this to work, it has to be an ice deposit, not permafrost. We then have to calculate the freezing/melting and boiling/condensing temperatures for water with that much salt. Calculate vapour pressure and evaporation rate. Calculate heat loss to the ground, what temperature hot water from the hose will be, and temperature of water in the pool. Calculate atmosphere temperature above the water in the cave. Calculate condensation rate on the ice cave roof. Will the roof freeze or melt?

Last edited by RobertDyck (2017-04-18 12:26:21)

louis · 2017-04-18 12:00:59

Dook,

It sounds almost as if you are saying that you constantly have to replenish water in your Mars greenhouse. I don't think you do, though, do you? It is a mostly closed system. The water evaporates off the leaves and presumably condenses somewhere...and can be collected thanks to gravity.

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