Re: Is it this easy to live on Mars?

On Sep 14, 9:49 am, Willie.Moo...@xxxxxxxxx wrote:
On Sep 14, 9:59 am, Quadibloc <jsav...@xxxxxxxxx> wrote:

On Sep 12, 8:03 pm, Willie.Moo...@xxxxxxxxx wrote:

Going by partial pressures;

Oxygen is 27,000x more plentiful on Earth

Colonists coming to Mars would bring a lot of extra oxygen and
nitrogen with them to get started.

You're not reading what I said with any understanding. If you
understood what I said, you would see that there is plenty of oxygen
nitrogen and water on mars.

They would not try taking Mars' thin atmosphere and compressing it to
obtain oxygen,

Why not? Have you run the numbers? If it only takes 6 watts per
person to separate ot the oxygen, why not? You're not getting it.

There are 25 trillion tons of gas freely available everywhere on Mars
- of that 32.5 billion tons of oxygen. 1.8 trillion tons of Nitrogen.
Enough of these gases to pressurize all of Mars surface to near Earth
normal pressure and a height of 5 meters (16.4 ft) - leaving the CO2
outside (except for 0.38% needed by Earth plants)

although they might have to obtain new carbon that way.

CO2 is 96% of the atmosphere. liquid CO2 is easily electrolyzed into
Oxygen and Carbon - but it takes FAR more energy to do that than to
merely pump up the oxygen that's already there.

To get oxygen, they would obtain it from the Martian soil,

They could do that, but its not necessary or desireable. There's
plenty of H2O on Mars, that can be electrolyzed into hydrogen and
oxygen - rocket fuels. But there's plenty of H2O in the air as well -
and that's easier than going and digging for it. I suspect that as you
reduced H2O in the air, it will sublime evaporate into the atmosphere
and maintain pressure. I also suspect that UV rays will break down
some of the H2O into O2 and H2 and the H2 will escape. Which is
likely where the oxygen came from in the first place. So, as we pump
the air down, the subsurface water, and the UV rays at high altitude,
will do a lot of this work for us.
.

Oxygen can be breathed. Breaking down H2O into 2 H2 and O2 takes far
more energy.than pressurizing oxygen that's already there. I did the
calculation. It takes 6 watts per person to run a pressurizer to
increase pressure 27,000x - and it takes 300 watts per person to take
1.125 liters of H2O and break it down into 125 grams of hydrogen and 2
pounds of oxygen per day. Obviously running the pump to pressurize
the existing oxygen is the way to go.

which is
largely made of rust (Fe 2 O 3) and which contains a fair amount of
water ice in many areas.

Um.. did you see the photos from the Phoenix? haha.. There's
permafrost under the martian soil. But, yes you can heat iron oxide
and get out water AND oxygen AND iron. But that takes even MORE
energy per person per day. ARE YOU GETTING IT YET? lol.

Actually, IIRC, the ice at one of the Martian poles is water ice, and
the ice at the other pole is dry ice,

What would account for the difference? sheez - you can actually look
stuff up, the same way Sarah Palin does, on Wikipedia

The polar caps at both poles consist primarily of water ice. However,
there is dry ice present on their surfaces. Frozen carbon dioxide (dry
ice) accumulates as a thin layer about one metre thick on the north
cap in the northern winter only, while the south cap has a permanent
dry ice cover about eight metres thick.[58] The northern polar cap has
a diameter of about 1,000 kilometres during the northern Mars summer,
[59] and contains about 1.6 million cubic kilometres of ice, which if
spread evenly on the cap would be 2 kilometres thick.[60] (This
compares to a volume of 2.85 million cubic kilometres for the
Greenland ice ***.) The southern polar cap has a diameter of 350 km
and a thickness of 3 km.[61] The total volume of ice in the south
polar cap plus the adjacent layered deposits has also been estimated
at 1.6 million cubic kilometres.[62] Both polar caps show spiral
troughs, which are believed to form as a result of differential solar
heating, coupled with the sublimation of ice and condensation of water
vapor.[63][64] Both polar caps shrink and regrow following the
temperature fluctuation of the Martian seasons.

so they could get carbon without
having to compress the thin Martian air.

Yeah, but please understand that if it takes less than 2% of the
energy to take freely available Mars atmosphere and get what you need,
why would you limit yourself to a specific spot and use 50x more
energy?

Nitrogen, though, is a big issue.

There's 20x more nitrogen than oxygen on Mars. If you can get all the
oxygen you need for every man woman and child at less than 6 watts per
person - why the hell would Nitrogen - which can be gotten for far
less effort - be a 'big issue'??

Fact is it isn't.

Eventually, it could perhaps be
harvested from comets,

Yes, if there weren't nearly a trillion tons of nitrogen freely
floating around the planet, obtained for very little expenditure of
energy with a very simple compression technique - used to inflate
bicycle tires - you may want to do that.

but it will be a limiting factor to Martian
biomass.

Really? When will we need more than 1 trillion tons of Nitrogen on
mars?

Moving to Mars? Bring your own fertilizer.

You are full of *** certainly, so you qualify! hahahah..

Lets see you pressurize the Mars atmosphere through a molecular sieve
that extracts nitrogen, and water - right? This gets about 12 kg of
each for about 400 watts of expended energy every 24 hours. You then
electrolyze half the water - That's 1,600 watts over 24 hours. This
gives you 0.67 kg of hydrogen per day and 5.33 kg of oxygen per day.

Combine the hydrogen obtained in this way to 3.12 kg of Nitrogen
chemically which forms 3.79 kg of anhydrous ammonia, leaving 8.88 kg
of Nitrogen in gaseous form. Mix the oxygen and nitrogen into a Mars
atmosphere at about 54 kpa - this is 53% Earth pressure, at 33% oxygen
level - same partial pressure of oxygen as on Earth.

So, expending 2 kW allows you every 24 hours to produce

3.79 kg of anhydrous ammonia
22.3 m3 'air' at 300K

That covers 4.4 sq meters of surface area with 'air' every 24 hours
for each 2 kW of pump capacity. This is about a 853 grams of ammonia
per square meter!

It takes about 210 kilograms of anhydrous ammonia per acre to grow
crops like wheat and corn in the US. That's 52 grams per square
meter. So, for each square meter of air - you also make 16 year
supply of ammonia fertilizer! This ought to be enough to grow a few
crops, an get nitrogen fixed in the biosystems.

So, I don't see looking at the numbers that this is a problem. If the
'domes' leak at a rate of 50% loss in 16 years - you can maintain
26,000 sq meters of land (6.5 acres) of 'domed' land with 1 kilowatt
of 'fixed' power. That is, each 2 kW source supports in the end a
dozen acres of domed space.

Each citizen in the USA requires about 1 acre of farm land to support
them - with food and fiber - including textiles and wood products.
So, mining the air in the manner I described originally - without all
the other stuff you mention - supports a half dozen people per
kilowatt.

Using enclosed agricultural techniques, developed by NASA among
others, we can expect 20x this yeild per acre. So, the same kilowatt
could support 120 people with modern scientific practice on the same
dozen acres. If we are clever with our mix of crops and animals and
optimize gas exchange etc., we likely can do better than even this.

So, I don't see the wasteland that you see, or the nee to do the sorts
of things you're talking about here. sorry.

Mars isn’t a “wasteland” unless you’re not much smarter than a dry-ice
frozen to death portion of Martian sod.

Technically Mars is humanly doable, as long as the public funded R&D
plus investments of time and mission cost are not factors, any more so
then the trauma and subsequent lethal consequences to human DNA seems
to not phase your apparently rad-hard mindset.

Btw, don’t forget to bring along tonnes of nitrogen fertilizer per
individual planning to survive long enough to die of cosmic radiation
or having a few meteorites penetrate their skull.

~ BG
.

Quantcast