DeGrasse Tyson's Mars challenge to Elon Musk

elderflower · 2017-04-23 13:48:41

Dook. I think that you will find a very high ambient humidity in your greenhouse due to plant transpiration. Then your Zeolite panels will take up more water rather than giving it up. Zeolites love water. This is why you have to heat it strongly in a very low humidity atmosphere to get the water out and not have it go straight back in. The amount of heat to be provided must exceed the heat of adsorption of water in zeolite at the temperature at which you are going to extract it, plus the heat of evaporation of that water, plus the thermal energy involved in making a large lump of zeolite quite hot, plus the relatively small amount required to heat the carrier gas. You don't get it all back in heat exchangers, either.

Dook · 2017-04-23 14:30:55

elderflower wrote:

Dook. I think that you will find a very high ambient humidity in your greenhouse due to plant transpiration. Then your Zeolite panels will take up more water rather than giving it up. Zeolites love water. This is why you have to heat it strongly in a very low humidity atmosphere to get the water out and not have it go straight back in. The amount of heat to be provided must exceed the heat of adsorption of water in zeolite at the temperature at which you are going to extract it, plus the heat of evaporation of that water, plus the thermal energy involved in making a large lump of zeolite quite hot, plus the relatively small amount required to heat the carrier gas. You don't get it all back in heat exchangers, either.

The zeolite would not release water vapor into a high humidity environment? Correct. You guys are always thinking many, many, years after a first settlement is established while I'm always thinking about the very first settlement.

I'm talking about when the greenhouse is first built. There won't be any plants yet, the atmosphere inside the greenhouse will be Mars CO2. We'll have a vacuum pump on the greenhouse pressurize the greenhouse. I know it will take some time, then we can use a fiberglass cart with zeolite panels on it every day in summer to get water vapor into our greenhouse. The water condenses on the inside of the greenhouse every night and runs down the inside of it into trays. We collect the water and put it into containers. Once we have enough water we can grow plants and the plants will turn the greenhouse CO2 into oxygen.

Also, in the ceiling of the Mars Hab there would be a WAVAR unit built in. That unit would still provide water to the Mars Hab.

Last edited by Dook (2017-04-23 14:31:54)

Oldfart1939 · 2017-04-23 16:03:13

Dook-

No. You do NOT know about zeolites. They need the water to be baked out of them, and than generally isn't anything like your 70 degrees Fahrenheit. We're talking more than 70 degrees Celsius. For laboratory re-use, we heated them that hot and pulled a vacuum at the same time. Then they were dry enough to re use.

Dook · 2017-04-23 16:49:24

Oldfart1939 wrote:

Dook-
No. You do NOT know about zeolites. They need the water to be baked out of them, and than generally isn't anything like your 70 degrees Fahrenheit. We're talking more than 70 degrees Celsius. For laboratory re-use, we heated them that hot and pulled a vacuum at the same time. Then they were dry enough to re use.

Zeolites need water to be baked out of them? I said that. You're claiming that I don't know anything about it but you just repeat what I said.

It generally isn't anything like 70 degrees F, it's more than 158 degrees F to outgas water vapor from zeolite? The greenhouse will be over 70 degrees F because that's Mars summer daytime temperature, so let's say it gets to 90 degrees F. Then we use the solar reflectors. Exactly how much hotter they will get the zeolite panels is a guess but if we can get the zeolite to 120 degrees F that will outgas a lot of the absorbed water vapor.

It doesn't have to be exactly 100%. You're never going to get all the absorbed moisture out anyway because the greenhouse will have some pressure and won't be a vacuum.

Plus, the WAVAR unit on the Mars Hab will be producing water too.

SpaceNut · 2017-04-23 18:16:38

So the greenhouse now needs an air lock, pumps to equalize pressures and a track or some other wheeled aligning system to be sure that panelized zeolite unit comes in from the outside to inside correctly only to do this all in reverse as we are growing things in the greenhouse.....

Leave the panels in alignment outside with a heat line going into the bottom of the panels from the greenhouse and a vent line at the top for the water vapor to exit during the day closing these off for night time refilling of the chamber with moisture. IF we really do need the heat source to be warmer to drive the moisture out then add the reflecting panels to aid the warm air coming from the greenhouse loop.

kbd512 · 2017-04-23 18:17:16

Dook wrote:

The WAVAR report assumes there is enough water vapor to absorb from the atmosphere? It does based on Viking 1, Viking 2, and Pathfinder water vapor measurements. They believe that Mars atmosphere has 100% humidity at night at low altitudes.

I didn't say we were guessing entirely, but you realize that .03 and .063 is a big difference.

Dook wrote:

The atmospheric pressure changes on Mars? It does but only by a few milibars. We have to select a base location that is low in altitude so the base has higher pressure to help with fans in the WAVAR, mini-Moxie, and to provide radiation and micro-meteorite shielding.

See above response. Being "off" a few millibars can mean the difference between a soft landing and hitting the surface of the planet at several hundred miles per hour. The variability of the atmosphere is not something to hand wave, even before you land.

Dook wrote:

The WAVAR uses seed hydrogen? No, it doesn't. The report does talk about seed hydrogen, it is confusing, but what they are saying is that the mass of the WAVAR was designed to be less than the mass of seed hydrogen, otherwise, why take a WAVAR at all when you can just take seed hydrogen.

The output level drops substantially without the seed hydrogen. WAVAR can make water with or without LH2, but it makes more with LH2.

Dook wrote:

I guess there are different kinds of zeolite, some absorb just water vapor and others absorb water vapor and CO2. Don't take my word on that, I'm still trying to figure it out but there seems to be a lack of detailed information about it.

There are, but the zeolite is not the problem. The continuous power requirement of 8kWe to 12kWe is. There's a big difference there.

Dook wrote:

The wheeled zeolite cart would have to contain a pressure vessel to prevent the water from outgassing back into the Martian atmosphere? It does not need a pressure vessel. The panels need to be exposed at night and they should have a fan to blow Mars atmosphere over the panels at night. The outgassing doesn't happen until you heat the panels so you push the wheeled cart back inside the greenhouse so they outgas the water vapor inside.

Umm... no. You need a solar oven and a pressure vessel. In the same way the SOXE uses sufficient heat to break the bond between C and O2, you need sufficient heat to extract the water.

Dook wrote:

I think the panels only need to be heated to 50 degrees F to outgas but I need to verify that.

That's a good idea. The process may start at 50F. The question is how much water is removed at that temperature and how long does it take.

Dook wrote:

The zeolite panels can't weigh 240 kg? Yeah, that's 528 lbs on Earth but only 200 lbs on Mars. That's why I want them mounted to a fiberglass cart on wheels.

If you kept WAVAR permanently mounted to the top of the habitat in its own pressure vessel, it'd make life easier. Use a fan and a fresnel lens mounted on a double hinge on the top of the pressure vessel to allow the fresnel lens to swing down and the fan to swing up. This could be actuated with a solenoid, so no requirement to leave the habitat module if the module was placed on the top of the habitat, where it would also contribute to radiation shielding. The water tank could be mounted on top of the module, empty for the transit, filled once on Mars. A single penetration of the pressure vessel would allow water from WAVAR to flow through a pipe and into the interior tank for storage. That way you have two tanks, the solar flare storm shelter in the center and the GCR shield on top. You still need to put regolith around the walls, but at least this setup is more technically feasible and does not require daily EVA's and all the problems those events create.

Dook wrote:

The quick and easy temporary greenhouse would just be to start getting water immediately on Mars with the zeolite cart and be able to boil urine to get water. Once the large permanent greenhouse is being built and needs those panels the temporary greenhouse would be torn down.

Would the greenhouses be connected to the habitat to avoid EVA's?

Dook wrote:

I mean a big RTG and a large thin solar array spread out on the surface. The Mars Hab would also have another circular solar array placed on top of it to cover the regolith. These are not solar panels, they are very lightweight thin solar arrays that can be stored rolled up in the Mars Hab for flight and rolled out on Mars.

How many RTG units are required? What's the power requirement? Is it just a minimal life support backup system or something more powerful. The "big" RTG's we had (now discontinued) put out 300We, BOL.

Dook wrote:

I know you guys want a nuclear reactor and massive amounts of power but once you get rid of all the production and manufacturing ideas you will realize that you don't need that much power.

Start adding up the electrical power requirements and then tell me if you don't think a nuclear reactor has an output level that more closely matches the requirement, as a function of the required tonnage.

Dook wrote:

You just need to power the Mars Hab (one mini-Moxie, the WAVAR, life support system, lights, laptops, DC shower pump, and CO2 scrubber), the fan on your greenhouse, the fan on your zeolite cart, and be able to recharge the two ATV's (the long range rover can recharge itself).

To produce enough O2 to keep four people alive, you need at least 8 of the 1% scale units, maybe 16 units with 8 offline spares. That's 1.344kWe right there for 8 online units. Let's call the mass 8kg per unit, so 64kg (EDIT: for 8 units) or just 1kg less than a 300We GPHS-RTG.

Avionics - We'll know more about this in the next two or three years as Orion flight testing. It's computers were purpose-built for extended duration operation in high radiation environments. I seriously doubt it's less than 1kWe.

Laptops - A current generation Macbook Pro requires 61We, but let's suppose that the maximum draw improves to 45We as a function of improved power efficiency between now and when the Mars exploration and colonization campaigns are ready to begin.

Lights - Let's call this 100We for all lighting requirements.

CAMRAS CO2 Scrubber - I had the actual power measurements from the ISS demonstrator unit and now I can't find it, but I seem to recall the figure was at or under 200We. The legacy CDRA units require 750We, for comparison purposes. One unit is intended to scrub the CO2 exhaled by 6 astronauts.

Paragon IWP Waste Water / Brine Filtration Unit - 86We. This is a jaw-dropping power consumption improvement over legacy systems and the overall mass and volume of the system is also dramatically lowered. The cycle length is rather long (days), so I believe two units are required for four to six astronauts.

Waste heat removal - Current technology systems use hot / cold plates with ammonia loops and require power hungry refrigerant pumps. This is less of a problem on Mars, but a very well-insulated module in a near-vacuum requires waste heat removal because the insulation traps the heat in the same way that it prevents extreme cold from affecting the interior of the module.

Dook wrote:

The extreme cold of Martian nights requires electric heating? The Mars Hab would be very, very insulated. It has an outer shell of carbon composite, an inner shell of 18" of fabric, a 6" thick water sack that is full, another 6" water sack that would be filling from the WAVAR mounted in the ceiling. When I was building my house I slept in a trailer at the bottom of my property. I didn't use the heater at night because it would kick on every 20 min or so and wake me up so I just used two blankets and a sleeping bag. It would be 17 degrees inside the trailer in the morning but I was warm, usually too warm. No fuel cell needed.

Cold kills Lithium-ion batteries and electronics. The fuel cells were only intended to power MOXIE used in conjunction with a WAVAR using seed hydrogen. If no seed hydrogen, then no fuel cells.

Dook wrote:

The Mars ISRU Springer estimates that their WAVAR unit would produce only 1kg of water a day? They use a different design and their zeolite is a 1 cm by 62 cm wheel. The amount of zeolite we take determines how much water we get. Oversize is better.

Oversize means more launch mass and more electrical power is required to generate sufficient atmospheric mass flow over the sorbent bed. There are no free lunches here.

Dook wrote:

This is another reason why taking a 3D printer and manufacturing equipment is bad for the first settlement. Everything you take to produce sulfur reduces the amount of oxygen equipment, water equipment, and food producing equipment you can take.

The robots are sent to Mars before the people show up and the mass of the water robots is already less than the mass of the WAVAR and the robots require far less electrical power output to do what they do.

Dook wrote:

Seed hydrogen is used along with CO2 in a Sabatier reaction to make methane and water. The problem is that you have to take seed hydrogen which adds launch weight and you lose most of it to boil off on the trip to Mars.

That's true, but the alternative is a much larger and heavier WAVAR unit. A gallon per day would take a year to fill a 365 gallon tank.

Dook wrote:

Now we're down to four from six people? Zubrin planned for four, not six. You can't take six. Six people means your consumables goes from 7 tons to 9 tons, and you have to produce more oxygen and water and have less extras. More people on Mars is not better, it's worse.

You originally stated your module would carry six people. Now were down to four. This colony is starting to take on the characteristics of an exploration mission. Four people isn't a colony. NASA is planning on sending more people than this on exploration missions.

Dook wrote:

I'm not looking at any video's. I'm going to assume that it's a video of something on the Earth and not Mars. Things don't work as well on Mars that they do on the Earth.

The physics behind how fluids like water work won't change to support your personal beliefs. You can spend 2 minutes educating yourself or remain ignorant. I really don't care. It won't change the fact that the basic principle of operation that the water robot uses to obtain water works quite well on Earth, Mars, or any other planet with a fluid pressurized by a temperature gradient.

Dook wrote:

The numbers for my WAVAR include seed hydrogen? No, they don't. You need to look up zeolite and see how it works. It doesn't use hydrogen.

What? I never made such a claim. Go back and re-read. I already reviewed how zeolite beds work. I'm intrigued and I'd like to figure a practical way to make it work that takes account of the math and science involved.

Dook wrote:

Your water robots have no batteries at all, it uses an RTG and super capacitors? That's for the drill, how does the vehicle move? What causes the ball to rotate?

I already explained how the ball rotates. It can steer, too. Again, there are a variety of YouTube videos and corporate websites that can explain how magnetic gearing and super capacitors work.

Dook wrote:

My WAVAR can produce about 365 gallons per year assuming it lands in a spot with twice the planetary average water vapor concentration? Correct, but we already know the higher latitudes have higher water vapor concentrations so it's not a guess. And 365 gallons a year will be enough IF the settlers don't waste it on rocket fuel.

You're fixated on this rocket fuel thing. The point of contention is the actual quantity of water vapor in the atmosphere, which varies from place to place.

Dook wrote:

The shelter needs to protect the crew from radiation? A Mars Hab that is thin carbon composite, 18" of hydrogen impregnated fabric, then a 6" water sack, and another 6" water sack, and some regolith on top isn't enough?

That can work. Now work out how strong the habitat module needs to be to support the weight and how much regolith you have to move to protect a habitat module 11meters tall.

Dook wrote:

The sulfur is all over the place on Mars? Estimates say it averages about 6% of regolith. That means you are going to have to move a lot of material and use a lot of heat over and over and over again just to get a small amount of pure sulfur for a home that no one is going to leave a Mars Hab for.

A fission reactor won't have any issue supplying the heat. Heck, if the regolith container is an oversized vacuum thermos a RTG won't have any issue supplying the heat required. Sulfur has a low melting temperature.

Dook wrote:

Your water robot is a 250 gallon tank with a drill? What causes the ball to roll? For the tank to suck up water vapor you need a fan, then you need to pressurize the water vapor to get it to condense (so you close the intake valve and pressurize the tank somehow), then you need a pump to move the water into a separate tank to store the water.

The ball uses magnetic gears rotated by electric motors to cause it to "roll". I think this is the fourth time I've explained this.

No fan or pump is required to get the water to the tank. That YouTube video would've provided a quick education on that point, but you elected not to watch it because it's not inline with your personal beliefs. It'll take a whole two minutes of your time.

Dook wrote:

Your robots will get water, process dirt, and build homes on Mars before a crew arrives? Okay, we'll be waiting a long time for that to happen.

You said you were ok with waiting and so am I. We need to explore before we colonize.

Dook wrote:

I want a crew to go outside every day to move zeolite panels? One person just before nightfall. It doesn't take two people. I want a buried habitat under the greenhouse so the crew would be living inside the buried habitat and could go up to the greenhouse without having to go outside. If you're so worried that something could happen there could be a person in the greenhouse watching the person move the cart outside.

In all real world EVA's, the astronauts don't just throw their suits on and shut the airlock behind them. I already explained how this process actually works. It's not something I made up because I wanted to argue the point with you. This is how it actually works.

The colonists inside the hab can watch the people out on EVA, but if they haven't pre-breathed then they're just spectators if something goes wrong. There's a reason that the EVA's performed from ISS involve to suited crew members. I believe the last reason was named Luca Parmitano. Thankfully, Christopher Cassidy was there to help his partner back to the airlock and they're both still counted amongst the living.

Dook wrote:

Astronauts have to prep before a space walk? They are breathing nitrogen. There won't be any nitrogen in the air in the habitats on Mars and if there is it would be in small amounts.

Apollo was the last US-built spacecraft to feature a 100% oxygen atmosphere. There were three very good reason behind the decision to deal with the complication of the two-gas system. Their names were Virgil Grissom, Ed White, and Roger Chaffee.

Dook wrote:

You've way over designed and greatly over complicated it. Get rid of the Rube Goldberg ways and keep it simple.

You way-oversimplified things. Some fundamental science course work combined with a willingness to learn is a good way to discern what will or won't work and what is or isn't all that complicated. I try to learn something new every day. I don't let personal beliefs get in the way of actually learning something. The zeolite panels are a good example. After learning what I did, I think the concept has potential and I stated as much in case you missed it.

I know this will be ignored, but the power requirement for WAVAR to work is about as high as all the other systems aboard the habitat module combined. It's not unmanageable, but I've seen enough hand waving of that issue and demonstrably false output rate figures thrown out that it makes me wonder whether or not you think you can will something to work or whether you're willing to figure out just how well something will work using some basic math and science.

I really wish you'd dig a little deeper into this stuff because that would add a lot of value to the discussion here. I've never said "I don't think WAVAR will work because I don't believe it will work." That's not an argument. It's a statement of opinion with no mathematical or scientific principle backing it. If I said, "I don't think XYZ aspect of this concept will work based on reasons ABC and here's the math or here's how we're currently doing things", then that's at least a technical argument about the merits or lack thereof of doing something some specific way.

Last edited by kbd512 (2017-04-23 18:25:25)

Dook · 2017-04-23 19:56:12

SpaceNut wrote:

So the greenhouse now needs an air lock, pumps to equalize pressures and a track or some other wheeled aligning system to be sure that panelized zeolite unit comes in from the outside to inside correctly only to do this all in reverse as we are growing things in the greenhouse.....
Leave the panels in alignment outside with a heat line going into the bottom of the panels from the greenhouse and a vent line at the top for the water vapor to exit during the day closing these off for night time refilling of the chamber with moisture. IF we really do need the heat source to be warmer to drive the moisture out then add the reflecting panels to aid the warm air coming from the greenhouse loop.

Yeah, the force applied is too much to open a hatch against greenhouse pressure. Going outside you would have to open a valve in the pressure door to let pressure into the airlock, go through the door and close it, turn on a pump in the airlock to pump some of that air back into the greenhouse before you exit the outer airlock door.

Going in to the greenhouse, the pressure should be the same so the outer airlock door would open fine. Then you would have to open a valve to allow greenhouse pressure in so you can open the door.

Really, this just shows the need to have the habitat inside or buried under the greenhouse so you don't have to go through the airlock very often.

We could leave the zeolite panels outside in a small self contained greenhouse and run tubes into the greenhouse? Yeah, we could do that. I think we would have to have two outer valves that open to allow Mars atmosphere to come in and circulate around the zeolite panels then they close in the morning and another two inner greenhouse valves open to allow warm greenhouse air to circulate. I like to keep things simple and this is getting more complex. Might not be worth it.

Sounds like the greenhouse needs it's own WAVAR unit or some way to get water from the WAVAR unit on the Mars Hab to the greenhouse.

Last edited by Dook (2017-04-23 19:56:46)

SpaceNut · 2017-04-23 20:36:09

http://www.ecoair.org/desiccant-or-compressor.html

https://www.sorbentsystems.com/desiccants_charts.html

http://www.solarmirror.com/fom/fom-serve/cache/35.html

Desiccants are materials with a high tendency to adsorb water. If a dry desiccant is exposed to the air, it will dehumidify the air, while the desiccant becomes warm. Eventually the desiccant will become saturated with water, but it can be "regenerated" by heating.
The most common desiccants are silica gel, calcium chloride (CaCl2), activated carbon, zeolites, lithium chloride (LiCl) and lithium bromide (LiBr).
Some desiccants can adsorb other liquids than water. Of interest are liquids which boil at temperatures somewhat below water's freezing point: methanol, ammonia, ethanol, methylene chloride.
Some desiccant links:
NREL desiccant cooling page
http://www.nrel.gov/desiccantcool/
EREC brief: zeolites in solar energy applications
http://www.eren.doe.gov/consumerinfo/refbriefs/ba3.html
Solar Adsorption Refrigeration Using Zeolite and Water
http://www.fh-luebeck.de/an/pt/solar/pu … ros-00.pdf
Kai Oertel's homepage, methanol/silicagel based adsorption cooling systems.
http://infoserv.kp.dlr.de/koertel
Zeo-Tech, makers of zeolite-water adsorption coolers and heat pumps
http://home.t-online.de/home/zeolith/e_index.htm

Oldfart1939 · 2017-04-23 21:05:08

Zeolites, a.k.a. Molecular sieves, have an additional use in removing other contaminants from organic solvents; i.e. removal of dimethylamine contaminant from dimethyl formamide. 4 Angstrom sieves will quantitatively accomplish this upon standing at room temperature. This is not widely known, but I reported this in the literature about 25 years ago. Very useful in the field of peptide chemistry.

Dook · 2017-04-23 21:23:51

kbd512 wrote:

kbd512

Do I realize that .03 water vapor (avg for Mars) and .063 (estimated north of the equator) is a big difference? To me it's not much of a difference at all. To WAVAR it matters, I wouldn't call it a big difference. The lowest estimated water production amount on the chart is for Viking Lander 1, about 3.79 kgs a day, so one gallon.

The invariability of the atmosphere can change things? So Mars could somehow stop producing water vapor? How?

The output level of the WAVAR drops substantially without the seed hydrogen? The WAVAR doesn't use seed hydrogen. You didn't even understand the report. The report says that NASA's Design Reference Mission needs 1200 kg of seed hydrogen to replace life support system losses. Then it says "WAVAR takes the place of this seed H2" Table 1, last sentence. What the report is saying is that this WAVAR idea, in comparison with NASA's idea of taking seed hydrogen, weighs less and is better for producing water on Mars.

How could zeolite and a microwave use seed hydrogen anyway?

The problem with WAVAR is the continuous power requirement of 8-12 kw? The intake fan wouldn't need to run continuously and even if it did that shouldn't be that much. The microwave wouldn't run continuously either. The movable bed would not move continuously. I don't know why they think it needs 8 kw of continuous power.

For a wheeled zeolite panel cart I need a solar oven and a pressure vessel? It's called a greenhouse.

It would be better if I kept the WAVAR permanently mounted to the top of the habitat in it's own pressure vessel? I would leave that WAVAR in place. Getting water from the tuna can to the greenhouse is why I wanted more zeolite panels on a cart at the greenhouse.

Solenoids actuate instantly, not slowly. To move something slowly you need an electric motor or an electric actuator. Maybe you should ask the AE's to explain it to you since you obviously don't have a clue.

In my idea, the habitat is buried under the greenhouse ground. There would be a pressure door at the top of the habitat, just for safety in case of failure of a greenhouse panel, but the pressure between the two would be the same.

How many RTG units would be required in my plan? Can't say yet, I haven't finished going over all that. We could build the greenhouse, dig out the center, build a habitat, partially bury the habitat, put the RTG in the ground, finish burying it to help heat the habitat and greenhouse.

The "big" RTG's we had are 300 watts? I thought there was a 600 watt one?

You need eight 1% sized Moxie's to supply enough oxygen for 4 people? Or two 4% sized models.

Avionics? The crew won't fly the spacecraft like in the movies. They will be along for the ride.

Laptops? I assume that each of the 4 crew would be on their laptops almost constantly when awake.

Waste water filtration? Have the crew use a hand pump. They need the exercise in space anyway.

Oversize means more launch mass and more electrical power? The Mars ISRU report undersized their zeolite. It just depends on how much you want to get.

The mass of the robots is less than the WAVAR? You can have your Star Wars rip off idea and I can have my idea.

A gallon a day would take a year to fill a 365 gallon tank? So it takes 365 days. It takes what it takes. With recycling a gallon a day is plenty for a crew of 4. The greenhouse would use shipped water to start with.

I originally stated my module would carry six people? No, I did not. I said if the Zubrin science area was used for rooms the tuna can COULD carry six. As I said, I would not do that until all oxygen tanks, water tanks, and food stores are full and operating well at the base.

Four people is not a colony? Call it what you want. Four people means plenty of extra food and extra spare parts for critical systems taken along. Six means just barely enough food and they had better hurry up with the greenhouse and it had better start producing some food quick.

The point of contention is the amount of water vapor in the atmosphere, which varies on Mars? The amount of water vapor does vary, not just from place to place but hourly and yearly, but it doesn't stop.

One thing fixes everything, all you have to do is slow down and stop trying to force too many people to Mars too soon.

I should work out how strong the habitat module needs to be to support the weight? The 18" of fabric that the Bigelow uses is supposedly stronger than concrete so it's very strong.

A fission reactor won't have any issue with supplying heat? No, it won't, but you have to move a lot of dirt, put it into a container on the reactor, heat it, use a long dipper to get the sulfur out and it will still have some regolith with it, then do this over and over and over again. And after all the work you get a home, not oxygen or food or water so there can't be any growth in population anyway.

Your robot ball uses magnetic gears rotated by electric motors to roll? So it's not just a 250 gallon tank with a drill like you said it was.

I didn't watch your video because I have limited bandwidth in the mountains and won't waste it on video's.

Pure oxygen is dangerous? It is. The mini-Moxie makes oxygen, not nitrogen. The plants in the greenhouse make oxygen, not nitrogen. So, we either have to bring a lot along, resupply them with it, or find some way of getting it on Mars.

The WAVAR uses too much power? The report says the fan has to spin at 500 rpm and that the unit needs a constant 8.6 kw but the fan would not operate in daytime, only at night to pull in Mars atmosphere, so, it doesn't make sense that it uses constant power. Also, the unit is only operated in summer, not winter, so I don't know why they're saying the 8.6 kw is constant. A regular kitchen exhaust fan only uses 6.4 watts to move 50 cfm of air on the Earth.

You wish I would dig deeper into this stuff and get an education? You're the one who doesn't know how a solenoid works and thinks the WAVAR uses seed hydrogen when it doesn't. Zeolite doesn't change hydrogen into water. Hydrogen and oxygen don't even make water until they are burned together. You're the one who needs to go and get "educated". You need to get over yourself. You're an AT2, not Einstein.

Last edited by Dook (2017-04-24 02:28:27)

SpaceNut · 2017-04-23 21:47:34

https://www.universetoday.com/35796/atm … e-planets/

WATER VAPOR IN THE ATMOSPHERE OF MARS: FROM PATHFINDER TO MARS POLAR LANDER.

Exchange of Water Vapor Between the Atmosphere and Surface of Mars

ATMOSPHERIC WATER VAPOR ADSORPTION FOR MARS IN SITU RESOURCE UTILIZATION.

Scientists 'map' water vapor in Martian atmosphere

https://arstechnica.com/science/2015/04 … e-on-mars/

One of the more common chemicals in the Martian soil appears to be perchlorate salts, which have been detected from orbit and found by the Phoenix lander. These salts—calcium perchlorate in particular—readily form hydrates, where water molecules are integrated into the crystal structure itself to form an energetically favorable conformation.

So no need to bring from earth just process and place into the system for use....

Dook · 2017-04-24 03:02:23

Zeolite Cart

The cart has five zeolite panels sealed inside an aluminum box on wheels. The cart would be placed inside near the wall of the greenhouse and hoses would be connected from the cart to a greenhouse panel that has two fittings for the cart hoses to fit on. The cart would have a fan inside that stays on constantly in summer to pull in Mars atmosphere at night to circulate around the zeolite panels. The Mars CO2 would leave through the second hose back to the outside. There could be manual valves on the cart to open and close the Mars CO2 supply.

The cart would also have two other openings, with manual valves, that would allow greenhouse air to circulate around the zeolite panels. The same fan inside the cart would pull in warm greenhouse air to circulate and take water vapor out into the greenhouse. So, in the morning, someone would close the Mars atmosphere valves and open the greenhouse valves and leave them open all day long. Solar reflecting panels could be placed to shine sunlight onto the aluminum cart to heat it up and help release water vapor.

So, no having to go through airlocks.

Last edited by Dook (2017-04-24 03:03:17)

kbd512 · 2017-04-24 05:09:51

Dook wrote:

Do I realize that .03 water vapor (avg for Mars) and .063 (estimated north of the equator) is a big difference? To me it's not much of a difference at all. To WAVAR it matters, I wouldn't call it a big difference. The lowest estimated water production amount on the chart is for Viking Lander 1, about 3.79 kgs a day, so one gallon.

As previously stated, it affects the mass and power requirements considerably.

Dook wrote:

The invariability of the atmosphere can change things? So Mars could somehow stop producing water vapor? How?

I never made any such claim, nor implied that the Martian atmosphere won't have any water vapor.

Dook wrote:

The output level of the WAVAR drops substantially without the seed hydrogen? The WAVAR doesn't use seed hydrogen. The report says that NASA's Design Reference Mission needs 1200 kg of seed hydrogen to replace life support system losses. Then it says "WAVAR takes the place of this seed H2" Table 1, last sentence. What the report is saying is that this WAVAR idea, in comparison with NASA's idea of taking seed hydrogen, weighs less and is better.

If the output is only a gallon per day for an electrical energy input of 8kWe, then the energy economics of obtaining the water don't compare very favorably to simply transporting LH2 from Earth if you produce the water fast enough. That was why I said we could run MOXIE off of fuel cells. The fuel cells take care of the brief high electrical output requirement and make water. It was a means to very quickly obtain the water using the seed LH2. By scaling the size of MOXIE appropriately the production rate is high enough that you have to run WAVAR for years to catch up to what MOXIE, fuel cells, and seed LH2 can produce in a matter of days.

There is about 111.19g of Hydrogen per kg of water. 365 gallons is about 1383.7kg. 1383.7 * .11119 = 153.85kg of Hydrogen. If you get to Mars in about 90 days or so, then the 1200kg of LH2 can produce more than 5 years worth of WAVAR output (assuming 1 gallon per day). That means you get 1,898 gallons of water in a matter of days. If the water tank is 33 feet in diameter, then the water tank contains about 3.55 inches of water. If the more modest 4 person habitat module is only 20 feet in diameter, then you get about 9.69 inches of water.

Dook wrote:

The problem with WAVAR is the continuous power requirement of 8-12 kw? The intake fan wouldn't need to run continuously and even if it did that shouldn't be that much. The microwave wouldn't run continuously either. The movable bed would not move continuously. I don't know why they think it needs 8 kw of continuous power.

Would you increase your power provisioning requirement by 50% for something that takes more than 5 years to fill the water shield when you can get the same amount of water in about a week using systems you already have to run to provide oxygen?

Dook wrote:

For wheeled zeolite panels I need a solar oven and a pressure vessel? It's called a greenhouse.

I'd be surprised if the zeolite panels didn't become more saturated with water from putting them in the greenhouse.

Dook wrote:

It would be better if I kept the WAVAR permanently mounted to the top of the habitat in it's own pressure vessel? I would leave that WAVAR in place. Getting water from the tuna can to the greenhouse is why I wanted more zeolite panels on a cart.

What's wrong with leaving the WAVAR permanently attached to the top of the habitat module?

Since the WAVAR and water tank are above the greenhouse, so you can gravity feed the water to the greenhouse, no pumps required. Simple.

Dook wrote:

Solenoids actuate instantly. To move something slowly you need an electric motor.

There are solenoids used to slowly actuate valves, for example. A stepper motor could also do the job, but it's heavier and requires a more sophisticated controller. I thought you wanted simple. A slow-actuation solenoid for this application would be pretty simple and light in comparison to stepper motors.

In my idea, the habitat is buried under the greenhouse ground. There would be a pressure door at the top of the habitat, just for safety in case of failure of a greenhouse panel, but the pressure between the two would be the same.

Dook wrote:

How many RTG units would be required in my plan? Can't say yet, I haven't finished going over all that. We could build the greenhouse, dig out the center, build a habitat, partially bury the habitat, put the RTG in the ground, finish burying it to help heat the habitat and greenhouse.

I'd just leave the RTG's under the habitat module. No possibility of running into them with the dozer there if they're located there.

Dook wrote:

The "big" RTG's we had are 300 watts? I thought there was a 600 watt one?

The 600We model is 2 GPHS-RTG's. The 900We model is 3 GPHS-RTG's. See where I'm going with this?

Dook wrote:

You need eight 1% sized Moxie's to supply enough oxygen for 4 people? Or two 4% sized models.

If you lose one of your 1% MOXIE units, you only lose 1/8 of your production capacity AFTER you've already lost 8 units. Redundancy. You said we could ship more MOXIE units before we ever concerned ourselves with robots and other stuff. The units are so light that I took your advice to heart and proposed 16 units for your habitat module so it was extraordinarily unlikely that all of your units would fail and even if your power output capabilities were unexpectedly reduced, you'd still have the ability make more O2 for the crew by scaling back production.

Dook wrote:

Avionics? The crew won't fly the spacecraft like in the movies. They will be along for the ride.

You realize that completely autonomous spacecraft have avionics aboard, right? The avionics are the rad-hard systems that handle life support, electrical power management, and communications.

Dook wrote:

Laptops? I assume that each of the 4 crew would be on their laptops almost constantly when awake.

I presumed that only 2 laptops would require power at any given time. That's like have one crew member monitor systems during their shift.

Dook wrote:

Waste water filtration? Have the crew use a hand pump. They need the exercise in space anyway.

The total power requirements for IWP are quite low and the pumps don't run 24/7. Why waste their time?

If you want them to exercise, send them a Bowflex machine.

Dook wrote:

Oversize means more launch mass and more electrical power? The Mars ISRU report undersized their zeolite. It just depends on how much you want to get.

I'd like to get the water in about two years time so the crew doesn't have to run and hide in the solar flare storm shelter every time there's a solar flare or CME.

Dook wrote:

The mass of the robots is less than the WAVAR? You can have your idea and I can have mine.

The robots are on Mars before the crew shows up. If a robot fails, nobody is affected. If WAVAR has a mechanical failure, then what?

Dook wrote:

A gallon a day would take a year to fill a 365 gallon tank? So it takes 365 days. It takes what it takes. With recycling a gallon a day is plenty for a crew of 4. The greenhouse would use shipped water to start with.

How much water will you ship from Earth? This supposition seems oddly familiar. I believe this is where we started.

Dook wrote:

I originally stated my module would carry six people? No, I said if the Zubrin science area was used for rooms the tuna can COULD carry six. As I said, I would not do that until all oxygen tanks, water tanks, and food stores are full and operating well.

Dr. Zubrin planned to send a crew of six people to Mars for an exploration mission. Now we're down to four to colonize Mars. Why not just skip the colonization effort and continue exploration if that's the best we can do?

Dook wrote:

Four people is not a colony? Call it what you want. Four people means plenty of extra food and extra spare parts for critical systems taken along. Six means just barely enough food and they had better hurry up with the greenhouse and it had better start producing some food quick.

If everyone is still living in Winnebagos in ten years, then Mars is an egregiously expensive RV park.

Dook wrote:

The point of contention is the amount of water vapor in the atmosphere, which varies on Mars? The amount of water vapor does vary, not just from place to place but hourly and yearly, but it doesn't stop.

It would be a good idea to get a better understanding of what yearly averages are at prospective landing sites.

Dook wrote:

One thing fixes everything, all you have to do is slow down and stop trying to force too many people to Mars too soon.

With only 4 people sent every two years, you won't have to worry about having too many people on Mars for decades, assuming any survive their power-limited and water-limited environments for more than a few years and don't develop brain damage from inadequate radiation shielding.

Dook wrote:

I should work out how strong the habitat module needs to be to support the weight? The 18" of fabric that the Bigelow uses is supposedly stronger than concrete so it's very strong.

Basic engineering principles are at work here. GW already explained how pressure vessels work and I'm leaving it there.

Dook wrote:

A fission reactor won't have any issue with supplying heat? No, it won't, but you have to move a lot of dirt, put it into a container on the reactor, heat it, use a long dipper to get the sulfur out and it will still have some regolith with it, then do this over and over and over again. And after all the work you get a home, not oxygen or food or water so there can't be any growth in population anyway.

If you have plenty of water and some power, then you have oxygen. ISS makes oxygen by electrolyzing water. That's real flight proven hardware.

I think you're right about the population growth. My plan is to find Sulfur deposits.

Dook wrote:

Your robot ball uses magnetic gears rotated by electric motors to roll? So it's not just a 250 gallon tank with a drill.

The spherical water tank has two permanent magnet arrays affixed to the inside, similar in appearance to the steel hoops on a whiskey barrel, except the "hoops" are on the inside of the Titanium sphere.

The drill robot has four sets of rollers that look kinda like the main bogies on a 747. The rollers on the bogies are not magnetic, but the shaft arm the rollers are connected to contain an electric motor and a special type of permanent magnet that either adheres to the surface of the sphere or repels, dependent upon what the distance is from the magnets inside the sphere. These special permanent magnets are known as polymagnets. The polymagnets are rotated with stepper motors. As the motor rotates, the magnets rotate, and torque is transferred to the sphere as the individual motors spin. Steering is accomplished by slowing the rotation of the motors on one side or the other. The drill robot climbs up on top of the sphere by using the drill pipe like a Kangaroo's tail and climbs down for drilling using the same method. Once atop the sphere, gravity and magnetic attraction keeps the drill robot glued to the top of the sphere when the magnets rotate to produce motion.

When it's time to drill, the robot uses the sphere as a counterweight by only connecting one set of roller arms to the sphere in order to raise the drill pipe to a vertical position. The drill robot can be relatively light and the drill pipe / bit relatively heavy without causing the drill robot to topple over when it positions the drill for drilling. The idea is to eliminate the structural mass normally associated with a truck and drilling rig. The spherical tank is the chassis and wheel. The four motors and attached magnets are the engine and steering gear. The fifth motor rotates the pipe for drilling. The super capacitors provide electrical power to the motors. The RTG charges the super capacitors. The hot drill bit head contains the same Pu238 material as the RTG, but encased in tungsten carbide. After the pipe has been inserted into the well, the pair of rollers still connected to the sphere roll the sphere over the top, whereupon all four rollers grab the sphere. The pipe is inserted into the magnetic stopper by having the drill robot back off the pipe. When the sphere is full of water, the rollers move the sphere off the robot, the pipe is removed from the well, the drill robot climbs back up on top of the loaded sphere using the pipe and rollers to roll back on top of the sphere, and then the robot uses a combination of its own weight (gravity) and electromagnets to roll the sphere back to the colony for offload. The drill pipe also functions as a parking brake during super capacitor recharging and as a method to get the ball rolling again.

The loaded weight is 1,001lbs or 455kg on Mars. A 250 gallon water tank is almost exactly 4 feet in diameter. If the robot is rolling downhill, then the motors act as a form of engine brake that simultaneously recharges the super capacitors and slows forward rotation. A switch combined with a resistive load could provide the braking effect after the super capacitors are fully charged. The robot can drag the bit to further increase braking.

There are three primary problems I can think of. The first is losing the pipe or entire robot from too much pressure in the well. The second is bending the pipe in or out of the well. The third is accidentally crushing or immobilizing the robot since the sphere loads water while it's on top of the drill robot. The weight is necessary to deal with pressure in the well. There are probably others I've not thought of, but sufficient pressure to load water definitely won't be a problem.

Dook wrote:

I didn't watch the video because I have limited bandwidth in the mountains and won't waste it on video's.

The sphere is a near vacuum and much colder than the hot drill head. In an enclosed space, if you heat one end of the space and chill the other, then whatever fluid is trapped in that space will move in an attempt to equalize the pressure. The pressure drop causes the water to get sucked into the sphere. This principle applies whether you're living in Texas where I live, in Colorado where you live, the moon, Mars, or another galaxy. When you see oil and natural gas come rocketing out of the ground after the drill head penetrates the pocket of hot fluid, the very same principle is hard at work. No pumps or other machinery are required to lift water to a height of 10m when the drill head is hot enough to melt aluminum and the temperature difference between the drill head and storage tank is hundreds of degrees.

Dook wrote:

Pure oxygen is dangerous? It is. The mini-Moxie makes oxygen, not nitrogen. The plants in the greenhouse make oxygen, not nitrogen. So, we either have to bring a lot along, resupply them with it, or find some way of getting it on Mars.

Going back to an earlier post, if there's nitrogen in the air then EVA's require hours of pre-breathing to avoid decompression sickness. That's why daily EVA's may be a bit much to ask of the crew. The alternative is an atmosphere that readily supports combustion of materials not ordinarily thought of as being particularly flammable, like velcro, for example. NASA and ROSCOSMOS decided to deal with the problems associated with N2 in the atmosphere a long time ago. That doesn't mean using a 100% oxygen atmosphere at partial pressure can't be done, because it was done decades ago, but it's very dangerous to do it.

Dook wrote:

The WAVAR uses too much power? Someone over designed it.

The people who came up with the WAVAR idea over-designed it, but you're betting your colonists' lives on the water production capabilities of a device you think is over-designed?

Dook wrote:

You wish I would dig deeper into this stuff? Get over yourself. You're an AT2, not Einstein.

You seem to have a habit of resorting to personal attacks when someone posts something that doesn't agree with your assertions. As much as I like learning from other peoples' ideas about how to do things, because I find the topic of space exploration fascinating, at this point I don't think my responses to you are going to elicit any sort of reasoned arguments and the continued personal attacks seem pretty childish to me. None of my responses to you were intended as personal attacks, but you've either decided to take my responses to your posts as such or it's your nature to engage in personal attacks when someone points out problems.

Dook · 2017-04-24 11:22:44

kbd512 wrote:

You seem to have a habit of resorting to personal attacks when someone posts something that doesn't agree with your assertions.

You never posted any insults? So these quotes directed at me are supposed to be compliments:

Is your Google broke?
Did you ever go to college?
So your Google is broke
Did you take any basic mathematics or science courses while you were there?
Invest some of your time to read them.
Some basic science course work would really help
The physics behind how fluids like water work won't change to support your personal beliefs. You can spend 2 minutes educating yourself or remain ignorant.
Go back and re-read.
I think this is the fourth time I've explained this.
I know this will be ignored.
I've seen enough hand waving of that issue and demonstrably false output rate figures thrown out that it makes me wonder whether or not you think you can will something to work or whether you're willing to figure out just how well something will work using some basic math and science.
I really wish you'd dig a little deeper into this stuff...
It's a statement of opinion with no mathematical or scientific principle backing it.

If I misunderstand your idea you can either ignore me and not reply or explain it again in different terms. I've had to explain things to you over and over again that you misunderstood. You don't understand that the WAVAR doesn't use seed hydrogen. You don't understand how a solenoid works. I never said I would take 6 colonists on the first settlement mission, I said on later missions I might if things were going well.

You want to play the "I'm smarter than you are" game here, but the problem is you're not smarter. You might know more about some things just as I know more about other things but neither one of us is smarter than the other.

Last edited by Dook (2017-04-24 11:23:52)

Dook · 2017-04-24 12:31:47

Dook wrote:

kbd512

If the Mars landing site gets the lowest water vapor on Mars it will affect the WAVAR output? Yes, it will.

If the output of WAVAR is only 1 gallon a day and uses 8kw of electricity then it's inefficient? It is. Something doesn't add up. 8 kw is way too much power for a fan.

Would I choose to use seed hydrogen and a fuel cell to make power and water on Mars in place of a WAVAR? No. The zeolite concept is better for water production on Mars this one design just uses way too much power. We just have to improve it. See post #212.

Once the greenhouse becomes too humid the zeolite panels won't produce much water if any? Correct. The zeolite panels at the greenhouse work to provide you with an initial supply of water that you would store in containers but once the greenhouse gets too humid the zeolite panels won't outgas their water vapor. The WAVAR unit on the Mars Hab would still function and provide water.

What's wrong with leaving the original WAVAR on the habitat? Nothing. I never suggested removing it. I just wanted a zeolite cart at the greenhouse to produce the greenhouse's initial water supply because the Mars Hab will need to use it's water to fill it's onboard water sack shielding and for the crew to use.

Since the WAVAR and water tank are above the greenhouse we can gravity feed water to the greenhouse? Right now I kind of like the zeolite cart idea I posted in post #212 but I need to come up with a way for it to work even when the greenhouse is humid.

Having eight 1% mini-Moxie's is better than having two 4% scale mini-Moxies? Having eight redundant systems is excessive. Flight controls use two systems and sometimes have a backup emergency system, not eight. Also, they would have a portable mini-Moxie unit on board to be used in the buried habitat once it's finished. And there would be an emergency oxygen or air bottle on board. And they would have their Mars suits with rebreathers.

Autonomous spacecraft have avionics aboard them? Yes, they have some boxes. I thought you were suggesting they need a pilot and a flight station.

Why waste the crews time hand pumping waste water through a filter? So you think they should use a bowflex for exercise and have an electric pump filter their waste water so they don't have to operate a hand pump? We're just going to have to disagree on that.

You'd like to get the water (by robot) in about two years? Fine, if it works.

If the WAVAR has a mechanical failure, then what? They fix it. If a microwave goes out they replace the magnetron. If the fan motor goes out they replace the motor. If a valve fails they replace the valve. They will have to have spares for critical life support systems.

Also, if they have the zeolite cart they will have two things providing water.

How much water would I ship from the Earth? Don't know, it would be carried in the outer water sack shielding. Zubrin listed consumables as being 7 tons and he used wet food so the crew got some of their water from the food.

Zubrin planned to send a crew of six? No, Mars Direct planned for four. The tuna can has four rooms. If I remember correctly, Zubrin initially wanted five, his partner Baker wanted three, the math came out to support a crew of four so that's what they went with.

If the colony is still living in a Mars Hab ten years after landing then Mars is an expensive RV park? Now we get the truth, it always comes out in time. You don't like the tuna can because that would not be better than just staying on the Earth. You only think people should go to Mars if there are nice homes there for them. The people who go will have to be checked out. They will have to want to go and fully understand how hard it is going to be. They can't be lazy, competitive with the "Joneses" next door, or want to show off their Mars home that the taxpayers back home paid for.

It would be a good idea to get a better understanding of what yearly averages are at prospective landing sites? We have satellite water vapor measurements for all of Mars.

If you have plenty of water and power, you have oxygen? Correct, but they're not going to have plenty of water for years. Eventually it might be enough that they could break it down and have an extra way to get oxygen but I would not have the electrolysis machine sent with the first settlement, maybe the second or third.

The ISS uses electrolysis to make oxygen? That's great when all of the water is sent to you from the Earth.

Your plan is to find sulfur deposits? Okay, a pile of sulfur would be better than trying to get 6% of it out of the regolith. It's definately an option for the future. I can't see any crew risking their lives for it at the first settlement.

Use nitrogen in the air or not? Initially, the crew would leave the Mars Hab in Mars suits until the buried hab and greenhouse are finished and pressurized. Then they won't be going outside very often except for routine maintenance (dust off solar panels, blow out dust filters), to fix things, or go and get newly arrived supplies. I initially did not like the idea of using nitrogen in the air but I agree, it's necessary to prevent a fire.

The people who came up with the WAVAR idea over designed it and I'm betting colonists lives on it? There's more than one WAVAR unit out there. As for the one being over-designed, I think it does not need to have the rack and pinion that moves the heavy zeolite bed. I also know that there is something wrong with the power requirements if they have a fan that needs a constant 8kw. No matter what, the colonists lives are going to be dependent on machines to provide them with oxygen and water.

Last edited by Dook (2017-04-24 12:33:06)

kbd512 · 2017-04-24 13:32:48

Dook wrote:

You never posted any insults? So these quotes directed at me are supposed to be compliments:

They weren't compliments or insults. If you had to explain how a rocket works to someone who'd never used an internal combustion engine before, would you start in a different place? I know I would.

Dook wrote:

Is your Google broke?
So your Google is broke

Since you explained your internet access situation, I understand why it is that you can't easily find some of this stuff on the internet. You can't find a house or apartment in our neighborhood that doesn't have high-speed internet access and none of the plans I could choose from the providers with offerings had any data restrictions. I wasn't aware that that was still a thing in 2017, apart from cellular service.

Dook wrote:

Did you ever go to college?
Did you take any basic mathematics or science courses while you were there?

I would like to know whether or not I'm talking to an auto-mechanic, a veterinarian, or a mathematician. I was relatively certain that algebra was required for any degree. I also thought some basic courses like chemistry and physics were mandatory, no matter what degree you have. I never looked at what the requirements for obtaining an English literature degree were because I was interested in computers and computer science required those courses to graduate.

Dook wrote:

Invest some of your time to read them.

When GW (our resident rocket scientist here on these forums) says, here's some information about how this works KBD, go read up on it, he's directing me to the answers to my questions. It's not any sort of insult to ask someone to do some work to find their own answers.

Dook wrote:

Some basic science course work would really help

Based on your responses and assertions, that's just a statement of fact. Maybe you forgot everything they taught you in college or maybe they never taught you what people with science majors were required to learn. I know I've forgotten most of the basic stuff computer science stuff I was taught. I know I haven't written any searching or sorting algorithms or a compiler since that time. If someone who works on compilers is a little short with me because he or she has explained something multiple times and it's fairly obvious that I never attempted to make an effort to figure it out, I would understand their frustration with constantly getting the same response to reworded replies that all attempt to explain the same thing in different ways.

Dook wrote:

The physics behind how fluids like water work won't change to support your personal beliefs. You can spend 2 minutes educating yourself or remain ignorant.

You said you wouldn't watch the video and it's a two minute video. You've said "I bet" and "I think" far more often than "I know" this is how this works. If you say that stuff often enough to people who actually do know because they were required to do actual experimentation, what do you think the response will eventually be? Think they might get tired of getting the exact same response that clearly isn't based upon any evidence?

Dook wrote:

Go back and re-read.

You stated that I said something that was the opposite of what I actually said. You've done that a number of times in this thread. I've made no attempts to obscure anything I've stated in this thread.

Dook wrote:

I know this will be ignored.

Was it ignored?

Dook wrote:

I've seen enough hand waving of that issue and demonstrably false output rate figures thrown out that it makes me wonder whether or not you think you can will something to work or whether you're willing to figure out just how well something will work using some basic math and science.

Are you willing to figure out how much something weighs or how much power it needs or not?

Dook wrote:

I really wish you'd dig a little deeper into this stuff...

Yes, I would like you to actually calculate what something weighs or how much power it requires. If you did that one time (quoting figures from a document doesn't count) it would make me think you were actually trying to figure something out, rather than just arguing for the sake of doing so or on personal belief.

Dook wrote:

It's a statement of opinion with no mathematical or scientific principle backing it.

This applies to any statement that starts with "I think" or "I believe" that offers no evidence to indicate why it is so. If I said I think or I believe anywhere and then offered no further evidence to explain why I think or believe something, then it's just my opinion.

Dook wrote:

If I misunderstand your idea you can either ignore me and not reply or explain it again in different terms. I've had to explain things to you over and over again that you misunderstood. You don't understand that the WAVAR doesn't use seed hydrogen. You don't understand how a solenoid works. I never said I would take 6 colonists on the first settlement mission, I said on later missions I might if things were going well.

You may very well be right about me not understanding how WAVAR works since I'm not a chemist. I've seen enough mis-quotations of the material from that document you provided to know that little of what was posted was derived from the document. You keep stating that it doesn't require X or Y amount of power when you could easily calculate how much atmosphere the fan can move and how much power it would take to push the blades through the CO2 at a given velocity with a given airfoil geometry. The people who wrote the document already figured that out for us and those were the numbers they came up with. Maybe you can do better than they can. If so, then prove their analysis wrong, but please show your work the same way they did so someone else can understand what you understand. If not, then expect most of the same types of responses you've received thus far.

Regarding the "slow actuating" solenoid, it's an electro-mechanical pneumatic or hydraulic device. A common application is preventing water hammering in solenoid actuated valves and there are numerous examples of these devices used in industry. Don't take my word for it, here's a link:

STC Valve - 2D150-500.pdf

Dook wrote:

You want to play the "I'm smarter than you are" game here, but the problem is you're not smarter. You might know more about some things just as I know more about other things but neither one of us is smarter than the other.

My responses have nothing to do with intelligence and everything to do with knowledge or experience. The most intelligent person in the world with no fundamental knowledge of how something works is a poor substitute for someone with knowledge of the device or process in question or training and experience using it.

I simply presume you're smart enough to find information on your own, can provide some basic reasoning for claims that stands up to cursory analysis when a claim is made, and will go on to revise estimates or figures if new information is available or the reasoning behind a claim was in error.

kbd512 · 2017-04-24 13:46:18

Dook wrote:

Dook wrote:
kbd512
If the Mars landing site gets the lowest water vapor on Mars it will affect the WAVAR output? Yes, it will.
If the output of WAVAR is only 1 gallon a day and uses 8kw of electricity then it's inefficient? It is. Something doesn't add up. 8 kw is way too much power for a fan.

This post has been more helpful at explaining why you want to do what you want to do than the rest were.

Regarding the power requirement for the fan, look at the mass flow it has to achieve. The atmosphere on Mars is very thin and the mass flow ranges into the thousands of kilograms. It can be done, but it requires a lot of power.

Dook · 2017-04-24 16:26:21

kbd512 wrote:

Dook wrote:
You never posted any insults? So these quotes directed at me are supposed to be compliments:
They weren't compliments or insults. If you had to explain how a rocket works to someone who'd never used an internal combustion engine before, would you start in a different place? I know I would.
Dook wrote:
Is your Google broke?
So your Google is broke
Since you explained your internet access situation, I understand why it is that you can't easily find some of this stuff on the internet. You can't find a house or apartment in our neighborhood that doesn't have high-speed internet access and none of the plans I could choose from the providers with offerings had any data restrictions. I wasn't aware that that was still a thing in 2017, apart from cellular service.
Dook wrote:
Did you ever go to college?
Did you take any basic mathematics or science courses while you were there?
I would like to know whether or not I'm talking to an auto-mechanic, a veterinarian, or a mathematician. I was relatively certain that algebra was required for any degree. I also thought some basic courses like chemistry and physics were mandatory, no matter what degree you have. I never looked at what the requirements for obtaining an English literature degree were because I was interested in computers and computer science required those courses to graduate.
Dook wrote:
Invest some of your time to read them.
When GW (our resident rocket scientist here on these forums) says, here's some information about how this works KBD, go read up on it, he's directing me to the answers to my questions. It's not any sort of insult to ask someone to do some work to find their own answers.
Dook wrote:
Some basic science course work would really help
Based on your responses and assertions, that's just a statement of fact. Maybe you forgot everything they taught you in college or maybe they never taught you what people with science majors were required to learn. I know I've forgotten most of the basic stuff computer science stuff I was taught. I know I haven't written any searching or sorting algorithms or a compiler since that time. If someone who works on compilers is a little short with me because he or she has explained something multiple times and it's fairly obvious that I never attempted to make an effort to figure it out, I would understand their frustration with constantly getting the same response to reworded replies that all attempt to explain the same thing in different ways.
Dook wrote:
The physics behind how fluids like water work won't change to support your personal beliefs. You can spend 2 minutes educating yourself or remain ignorant.
You said you wouldn't watch the video and it's a two minute video. You've said "I bet" and "I think" far more often than "I know" this is how this works. If you say that stuff often enough to people who actually do know because they were required to do actual experimentation, what do you think the response will eventually be? Think they might get tired of getting the exact same response that clearly isn't based upon any evidence?
Dook wrote:
Go back and re-read.
You stated that I said something that was the opposite of what I actually said. You've done that a number of times in this thread. I've made no attempts to obscure anything I've stated in this thread.
Dook wrote:
I know this will be ignored.
Was it ignored?
Dook wrote:
I've seen enough hand waving of that issue and demonstrably false output rate figures thrown out that it makes me wonder whether or not you think you can will something to work or whether you're willing to figure out just how well something will work using some basic math and science.
Are you willing to figure out how much something weighs or how much power it needs or not?
Dook wrote:
I really wish you'd dig a little deeper into this stuff...
Yes, I would like you to actually calculate what something weighs or how much power it requires. If you did that one time (quoting figures from a document doesn't count) it would make me think you were actually trying to figure something out, rather than just arguing for the sake of doing so or on personal belief.
Dook wrote:
It's a statement of opinion with no mathematical or scientific principle backing it.
This applies to any statement that starts with "I think" or "I believe" that offers no evidence to indicate why it is so. If I said I think or I believe anywhere and then offered no further evidence to explain why I think or believe something, then it's just my opinion.
Dook wrote:
If I misunderstand your idea you can either ignore me and not reply or explain it again in different terms. I've had to explain things to you over and over again that you misunderstood. You don't understand that the WAVAR doesn't use seed hydrogen. You don't understand how a solenoid works. I never said I would take 6 colonists on the first settlement mission, I said on later missions I might if things were going well.
You may very well be right about me not understanding how WAVAR works since I'm not a chemist. I've seen enough mis-quotations of the material from that document you provided to know that little of what was posted was derived from the document. You keep stating that it doesn't require X or Y amount of power when you could easily calculate how much atmosphere the fan can move and how much power it would take to push the blades through the CO2 at a given velocity with a given airfoil geometry. The people who wrote the document already figured that out for us and those were the numbers they came up with. Maybe you can do better than they can. If so, then prove their analysis wrong, but please show your work the same way they did so someone else can understand what you understand. If not, then expect most of the same types of responses you've received thus far.
Regarding the "slow actuating" solenoid, it's an electro-mechanical pneumatic or hydraulic device. A common application is preventing water hammering in solenoid actuated valves and there are numerous examples of these devices used in industry. Don't take my word for it, here's a link:
STC Valve - 2D150-500.pdf
Dook wrote:
You want to play the "I'm smarter than you are" game here, but the problem is you're not smarter. You might know more about some things just as I know more about other things but neither one of us is smarter than the other.
My responses have nothing to do with intelligence and everything to do with knowledge or experience. The most intelligent person in the world with no fundamental knowledge of how something works is a poor substitute for someone with knowledge of the device or process in question or training and experience using it.
I simply presume you're smart enough to find information on your own, can provide some basic reasoning for claims that stands up to cursory analysis when a claim is made, and will go on to revise estimates or figures if new information is available or the reasoning behind a claim was in error.

Next time, not so much starch in my shirts squidy.

And can you and the wife kick up the smoking to two packs a day each? My cigarette stocks aren't producing as much as they were.

Last edited by Dook (2017-04-24 17:25:24)

SpaceNut · 2017-04-24 17:33:55

While the cart concept fits the bill and does show something that will work though its to an unknown quantity of water gained. Then its at a penalty of bringing mass from earth to make function. Is there a way to prove the cart design out to aid in minimizing the design masses of all components in order to produce the specific amount of water under testing environment of mars?

I think that the soil processing can be done in a simular manner to gain water that is trapped in the soils at night as frost into a thin tray design with the same solar heating during the day to cause water to evaporate out of the soils as there is percolates which will do the same function as the desicants that we would be shipping to mars.

Dook · 2017-04-24 17:48:10

SpaceNut wrote:

While the cart concept fits the bill and does show something that will work though its to an unknown quantity of water gained. Then its at a penalty of bringing mass from earth to make function. Is there a way to prove the cart design out to aid in minimizing the design masses of all components in order to produce the specific amount of water under testing environment of mars?
I think that the soil processing can be done in a simular manner to gain water that is trapped in the soils at night as frost into a thin tray design with the same solar heating during the day to cause water to evaporate out of the soils as there is percolates which will do the same function as the desicants that we would be shipping to mars.

Other than atmosphere changes (humidity, temperature) the amount of water vapor a zeolite machine (WAVAR or zeolite cart) can produce are dependent on the amount of zeolite used, the amount of atmosphere moved by the fan over the zeolite (at least until if gets full), and the final heating to release the water vapor.

Also, the humidity in the area that you are heating the zeolite affects the amount of water vapor the zeolite will release. So, I need to figure out how to continue to use the zeolite cart in a greenhouse that has full humidity. Or, perhaps have the zeolite cart in a small separate greenhouse connected to the main greenhouse with large hoses.

Soil processing can be done to get water? Yes, small amounts, but that would require daily excursions outside the greenhouse to move material whereas the WAVAR unit on the Mars Hab and a zeolite cart in the greenhouse will collect water using just electrical power.

Last edited by Dook (2017-04-24 17:49:00)

kbd512 · 2017-04-24 17:54:16

Dook wrote:

Next time, not so much starch in my shirts squidy.

Next time, wear that shirt right and we won't have to put so much starch in it to make you look half-way presentable to the Captain. Straighten up that gig line while you're at it, civvy.

Dook wrote:

And can you and the wife kick up the smoking to two packs a day each? My cigarette stocks aren't producing as much as they were.

They'll put your carcass in the same place they put mine when we kick over. My time here has been a pleasure. Has yours?

SpaceNut · 2017-04-24 18:26:23

Percolates are a natural desicant.....so move once and use in the same manner....

Water discovered in Martian soil

Scoop up some soil on Mars, heat it up, cool down the steam and ... slurp, slurp! You've got water!
Research recently published suggests that the soil from the Martian surface contains about 2% water by weight.
The rover's Sample Analysis at Mars (SAM) instrument helped scientists probe the soil by heating a sample up to 835 degrees Celsius. The gases that came off included oxygen and chlorine as well as water vapor.

Mars soil contains a huge amount of water, reports NASA’s Curiosity rover

If you heat up a cubic foot of Mars soil, you can harvest around two pints (one liter) of water. Basically, the GC heats up a soil sample by passing hot (~835C, 1535F) helium gas over it, and then measures the gases that emerge. In this case, by far the most common gas released (between 1.5% and 3% by weight) was water vapor. Per cubic foot of Mars soil, this equates to a lot of water — around two pints, or almost a liter.

Dook · 2017-04-24 19:48:55

SpaceNut wrote:

Percolates are a natural desicant.....so move once and use in the same manner....
Water discovered in Martian soil
Scoop up some soil on Mars, heat it up, cool down the steam and ... slurp, slurp! You've got water!
Research recently published suggests that the soil from the Martian surface contains about 2% water by weight.
The rover's Sample Analysis at Mars (SAM) instrument helped scientists probe the soil by heating a sample up to 835 degrees Celsius. The gases that came off included oxygen and chlorine as well as water vapor.
Mars soil contains a huge amount of water, reports NASA’s Curiosity rover
If you heat up a cubic foot of Mars soil, you can harvest around two pints (one liter) of water. Basically, the GC heats up a soil sample by passing hot (~835C, 1535F) helium gas over it, and then measures the gases that emerge. In this case, by far the most common gas released (between 1.5% and 3% by weight) was water vapor. Per cubic foot of Mars soil, this equates to a lot of water — around two pints, or almost a liter.

A cubic foot of Mars soil has almost a liter of water in it? That's more than I would have figured.

The test used 1,535 degree F helium gas though, I think that's too hot to consistently produce on Mars without using a lot of power. I think the best we could hope for would be a 90 degree F greenhouse and then some tall solar reflectors, so, maybe 120 degrees at most. Unless we use microwave heaters on the regolith.

I think we would run into the same problem the zeolite cart would have, once the greenhouse is pressurized and becomes humid the zeolite, or in this case Mars regolith, won't outgas water vapor into that humid greenhouse environment.

It's almost like we need two greenhouses, a large one that is humid and pressurized to 5 psi for growing plants, and then another smaller greenhouse that only has 2 psi and is used to vent zeolite and bucket loads of regolith so water vapor can outgas and be captured by a dehumidifier.

SpaceNut · 2017-04-24 21:16:22

The high temperature are used to vaporize all of the sample to a plasma like state for the sensor to tell what it had in the measurement and not just for the water. Microwave is a possibility for the same heating to drive off the water vapor.
As far as the extra greenhouse due to moisture build up we would once we have water pump it into the many empty fuel tanks to hold until we need it.

kbd512 · 2017-04-25 08:01:28

SpaceNut,

Does this mean digging in the ground for water isn't the worst idea, ever?

Let's say the regolith only contains .5L/ft^3 on average and our bucket holds 3 cubic feet of water, takes 2 hours to bake out the water using solar heat that we can only get during the day, we only extract 75% of the water, and as a function of available solar heat the machine can only be operated 4 times per day?

.5L * 3ft^3 * .75% extraction rate * 4 extraction attempts per day = 4.5L/day

1 gallon = 3.785L

1.19 gallons/day

Let's say the machine requires 2kWe to dig for a period of 15 minutes to completely fill the regolith bucket.

2kWe * .25hrs = .5kWh of electricity.

Current Lithium-ion technology is .25kWh/kg, so 2kg of batteries required for each 15 minutes of digging, after which solar heat starts heating a molten salt container to heat the regolith bin to extract the water. At 80% DOD, 2.6kWh of capacity is required, so a little over 10kg of batteries are required to complete a day's worth of digging. Let's say the entire robot weighs 75kg with batteries and we have a spare 10kg of batteries that are in a charger that a solar panel uses to recharge the batteries.

An ATK MegaFlex array provides .25kWe/kg at Earth, .125kWe/kg at Mars. Actual mass is 7kg/kW, so 36.4kg for the solar array to provide 2.6kWh worth of electricity to recharge the rover's spare batteries. The total mass (rover + spare battery set + solar array) of the solution is 121.4kg.

This seems to be within the realm of feasibility and requires substantially less energy investment than WAVAR for the same or better output per day. This robot is also far less complicated than a ball balancing robot, even if it doesn't extract as much water over a given time period. It's half the weight of the ball balancing robot, too, so two of these machines cost the same money as a ball balancing robot.

For 250kg worth of mass delivered to Mars, we can have two of these machines deliver an average of 71.4 gallons per month or 856.8 gallons per year. That compares favorably with the 125 gallons per month that the drill robots would deliver, presuming an average drill and travel time of about 2 months per trip to the glacier. For 100kg less mass than the 850kg WAVAR unit, 6 robots could deliver 2,570.4 gallons per year and require 15.6kWh/day. Just 2 hours of WAVAR operation would require 16kWh worth of electrical output.

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