New Mars Forums

Hi GW Johnson. You're right to a point. However, since Mars Global Surveyor we have discovered there are a log of hydrated minerals. These include clay. Scientists had said that you can't call any surface material "soil" if it doesn't include organic material. They had called everything on Mars "regolith". However, after years of studying the surface in all it's detail, they got tired of that. They now called bedrock "bedrock", they call boulders boulders, they call stones stones, they call gravel gravel, they call sand sand, and that loose stuff that looks like dry dirt that covers the surface of the planet they now call "soil". It doesn't have any organic material, but with ground rock with particle size smaller than loess, together with simple clay, they might as well call it "soil".

Processing sewage to be suitable for growing plants is tricky. You have to break down feces into something plants can use. That means some sort of microbe, either a soggy pile of solid material (composting) or shredding the "logs" to be suspended in water as a brown liquid (digester). Either way the microbes can be finicky. Contamination of food crops with fecal coliform is another danger. I'm trying to avoid that by just using Mars "soil" with carbonated water and ammonium nitrate fertilizer. Once you have crops, then use shredded stems and leaves from the previous crop.

Upon landing on Mars, unpack all surface equipment. That includes science instruments, garage tent for the rover, and your inflatable greenhouse. The greenhouse would be held down with large tent pegs. Shovel soil into trays. Inflate the greenhouse with a tank of stored air. Set up the trays, an awning inside the greenhouse to reflect heat at night, open it during the day. Again, not my idea, I got that from Dr. Boston's paper. Hang artificial lights, and wire them up. It may take a day or two to get the greenhouse set up. And the astronauts will be called upon to take science measurements. Use an air pump to pressurize Mars atmosphere, that will take a few hours, but can be done at night while they sleep. Then take a bottle of water and pressurize with this Mars atmosphere. That will create soda water, to soak the soil in the trays. Then plant seeds. All this in the first week after landing.

I have a few packages of seeds for garden vegetables. The package records number of days from planting to harvest:
Carrot - Jumbo (coreless) scarlet nantes: 68 days
green pepper - Early California Wonder: 75 days
Corn - Canadian Early Supersweet Hybrid F1: 65-70 days
Peas - Sugar Snap (Edible Pod): 70-75 days

I looked up the website of this seed company, they have more seeds available. http://www.mckenzieseeds.com
Tomato - Rio Grande: 75-85 days
Lettuce - Summertime: 75 days

Thank you for replying louis. But I believe hydroponics is complex, because of that solution. You can stack layers with soil trays, so that isn't an issue. Here's an example from the Mars Homestead Project, phase 2.
http://www.marshome.org/images2/albums/ … cam-2C.jpg

However, I still argue for ambient light greenhouses. I could go only about life support, but every system has a single point of failure: power. Plants are the only means to recycle air and water without power. But that doesn't work if the greenhouse requires power for artificial light. So for life support backup, I want greenhouses that are long and narrow, long east/west with mirrors on either side to reflect sunlight in through the sides. This will double total illumination, and the mirrors don't have to track the sun. At dawn, sunlight reflects westward by the distance between mirrors and greenhouse. At noon light reflects straight in. When the sun sets in the west, light will reflect eastward, again by the distance between mirror and greenhouse. The only tracking will be for seasons: adjust mirror angle 1/2° every second week to adjust for sun altitude. (The astronomy use of 'altitude', not height.)

The more I read of results from Mars probes (orbiters, landers, and rovers), the more I realize Mars soil is the same as Earth. The only exception is superoxides, and those decompose in seconds upon exposure to liquid water. You know, releasing oxygen by soaking soil is a good thing. It helps inflate the greenhouse.

As for feces, that's more complicated. But that's for a more established settlement. An initial science mission should just use Mars soil alone. Terry Kok has done some work with feces, he found a composting toilet is simpler and more stable than a grey water sewage processing system. Of course the BioMars guys would disagree.

You seem to want to play with semantics. I don't. My point is clear. Let me restate, again, there is no real tangible value in mars. Stop. There is no real economic model for earth-mars. Stop. Any realistic model is 50 years out. Stop. Musk is building towards mars as an act of charity. Stop. relying on charity for your long term plans is a poor strategy. Stop.

Reality tv and logos does not a business plan make. but what do I know. Enjoy your kingdom of kazoos.

Well, that certainly is interesting.  Do you by any chance have any more technical links on the subject?

louis wrote:

(.../...)
I have read that the steel used in some swords produced in the medieval period was as good and strong as anything produced in modern steel factories.  I take some comfort from that. I am fairly confident that we can create high grade steel in small scale furnaces with modern methods.

This I agree. But you have to remind that it was a matter of weeks to build one single sword of that quality. The tough part will be to scale up. (my guess here is that we will send a few of bug machines ina  few flights, & with them create all others needed. But we need the first few ones imported, should be cheaper than recreating them from scratch on-site)

For the 3D-part, they still don't give any example of heavily-mechanically-stressed part. Where they begin to shine of for parts where shape is more important than mechanical properties. And they will even more. Yet, I have to see a poppet valve made in 3D. I'm not sure we'll see soon.

And there will be also need for that kind of parts. In a mechanical system, machining quality may improve a lot the energetic efficiency. Surface quality, especially, can't compare. For a stirling engine, for example(I know pro-solar energy people here think about them), the better the surface of the cylinder is, the more efficient it will be. 3D printing is pixellisation of the steel. You don't make circles as good in pixels than with a compass for drafting.

Bottom line is that we will probably need both, for different usages. The ability to make very complex shapes will probably be useful for fluid management(for example). Yet, standard, older methods will still be critical where mechanical properties or surface quality will be critical.

All your silly buzzwords aside, producing something does not make an economy. I'm sorry that my poor metaphor failed- i really can't make this any plainer.

But I digress, go make your kazoos- afterall, production = economy.

My original point is that Musk is motivated from a point of charity. I applaude him, but it makes for a poor long term plan to depend on personal charity.

An email list had this link to a NASA study of food for a Mars mission. There are a few things I want to comment on.

http://www.npr.org/2012/07/24/157313902 … rs-mission

First, the person says a Mars greenhouse would use hydroponics instead of soil. That's got a problem: the nutrient solutions. Any hydroponic system requires several highly concentrated nutrient solutions, and these bottles of liquid are heavy. The weight of those supplies is extensive, hauling that to Mars is highly questionable. You could try to make them on Mars, but extracting them from Mars soil and purifying and concentrating to what's required for hydroponics? That would take a lot of equipment. Again weight, we need to minimize anything we send from Earth. For reliability we also have to keep it simple; remember the engineering mantra: KISS = Keep It Simply Stupid.

This is why I recommend simple soil. Shovel some Mars soil into a pressurized greenhouse, add water, grow crops.  Ok, so what do we have to do soil to make it suitable? Mars Phoenix measured soil pH. What it found is what scientists expected based on mineral composition measured by previous missions. Phoenix measured pH 7.7.

http://www.space.com/12695-mars-soil-li … study.html

Neutral pH is 7, so that's ever so slightly alkaline. Most food crops want slightly acidic soil, but you could grow something like asparagus. But this can be treated with simple means. Simply bubble Mars atmosphere under pressure through water. This will create carbonated water, also known as soda water. Mars atmosphere is 95.32% CO2, 2.7% N2, 1.6% Ar, as measured by Viking 2. Earth's atmosphere is 78% N2, and 0.9% Ar. Carbonated water typically has pH between 3 and 4, making it a mild acid. Actually, CO2 dissolved in water is called carbonic acid. This will help neutralize alkaline soil. In fact, this has already been tried by gardeners. The following link talks about adding carbonated water to plants.

http://www.gardenguides.com/131867-effe … lants.html

The acid will dissolve alkali minerals from soil, this is an acid-alkali reaction. Dissolving them into solution makes them readily available to plants. Although the link suggests you have to be moderate with carbonated water, too much is bad for plants.

If you look at all the nutrients in Mars soil, it has everything needed to grow plants. It is low in carbon, but adding carbonated water will help with that. Soil is also low in nitrogen; in fact Mars rovers have not yet discovered any nitrogen at all within detection limits. The APXS instrument has a threshold of 0.1%, so nitrogen is less than that. Ok, so we need to add nitrogen fertilizer. Can you say "ammonium nitrate"? I knew you could.

Fertilizer used on Earth is normally measured in "K-P-N", that is three numbers representing the concentration of potassium, phosphorus, and nitrogen. Simply by selecting the right patch of Mars soil we can get enough K and P.

I could describe how to make ammonium nitrate, but for obvious reasons I do not want to post that on the internet. Let's just say we can make it.

So let's see, this means a Mars greenhouse requires Mars soil, Mars atmosphere, water, breathable air to fill the greenhouse, and this one single fertilizer. That sounds a lot simpler than trying to make hydroponic solutions.

I wrote the former entry some hours ago, forgot to hit 'submit'

Maybe now I'm a bit more clear in the head, grin.

I think it will be some kind of 'stakeholder' bonanza, like in the goldrush, but not poor guys trying for their luck, no.  More like the big corps trying to be first and patent the h*ll out of things they do there 'first'   

you think patent wars are bad today? Wait untill we set foot on Mars...

MitshubichiSuperCorp hitching a ride with a small dumptruck in their luggage, using it there for a week and saying 'hey we invented a NEW way of hauling regolith!' and claiming any possible future mining rights through their technique. et c.

speculation in the extreme.

'We can't let the other guy (rival company) get away with an opportunity like that!'

Meanwhile, they set up outposts et c, demand for transportation rises, etc etc.

people end up there, first the loyal companymen in the extreme, later more mundane workers and jack of all trades....

And then of course there's an uprising   and Mars wil be free, free free!

louis wrote:

We ought to take those words and put them up on a plaque in the first Mars base in 2022.

Second off, what you bring back will have a huge saleable value: regolith and meteorites will be selling for hundreds of dollars a gram. Not just that - but virtually any item from the first mission will have high value to science based museums around the world who again will be paying hundreds of dollars a gram. If a museum gets just an extra 10 people per day through the doors because of a Mars related exhibit they might raise over $30,000 a year. Over ten years that's an extra $300,000 revenue.   That's why they can afford to splash out $100,000 on a little selection of objects that have been to or come from Mars.

If we used your Mars base in the next 10 years date,

The first Mars mission lander will not have the ability to bring back vast amounts of rock; what little rock will be brought back will be used for scientific study, and even if it was sold along with any "first mission tech" (unlikely; it seems more approprate / probable that after the "artifacts" are studied to the fullest extent, they'll be donated to the high profile museums of the participating countries (Smithsonian, State Hermitage ect.) )- the money made from the few peices brought back would be insignificant compared to the price of the actual launch - using only the first mission - you would never break even from the sale of Mars rocks, so you would never make any money. Very unlikely that you would get an absolute return on your investment right away (definitely not from the first), unless a better technology is used - which may not happen for the next 4 or 8 years due to political and economical contraints.

This thread of for comparing detailed mission plans focusing on Propulsion methods.  GW has produced a modular NTR based mission with spin based artificial gravity

http://exrocketman.blogspot.com/2012/07 … icial.html

And I'm going to do a SEP counter proposal in equal detail, but first I'm going to try to get the ground rules established to allow as complete and apples-2-apples comparison.  I've looked over GW's mission and extracted what I think are the criteria that need to be replicated.

* Launch constraints on volume and mass of Falcon Heavy (~50 mt), with option to use other EELV's.

* Trajectory from LEO to LMO and back again bringing the transit habitat back to LEO but leaving the lander mass in LMO for it's mission to be conducted from.

* Offload 120 mt of lander/surface payload modules at LMO massing 30 mt each.

* Provide 50 mt of Habitat module/s during transit (reusable) and 50 mt of Consumable filled module/s each for out and inbound transit.

* Transit times and total mission duration of 2-3 years with interplanetary transit times of 6-8 months