New Mars Forums

This Feb 2001 Caltech paper ...

http://www.its.caltech.edu/~boxe/boxe1.pdf

says Fluorine is actually a little more common on Mars than on Earth - 30 ppm vs. 20 ppm.  On Earth, 4.5 million tons of fluorspar (fluorite ore) is produced annually.  It costs about $150/ton.  It takes about 2.2 tons of high grade fluorspar to make 1 ton of HF.  Apparently the production of HF involves the highly sophisticated "stir ore with water" technique.  The Caltech guys would like at least 200 thousand tons of HF per year, but of course, the more the merrier.
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Thanks    This was originally Siegfried's thread, so I'm still kinda writing for him as well.  I think graphs can help a lot sometimes.

Zubrin's still calling 300 mb of CO2 pressure with a 5-10 K temperature boost.  That puts us at global -60° C, so we've still got a ways to go before we have to deal with water vapor.  I'm thinking we'll see 600 mb before we see H2O snow.  At that pressure, water should behave pretty much as it does on Earth.  In fact, the triple point of H2O is 6 mb - about the average surface pressure on Mars right now.  So liquid water should be possible in the valleys and during the middle of the Martian Summer when temperatures like +15° C have been recorded.  But don't tell Seaerlas, it'll only encourage him.

  I think that is the truth.
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Awesome!  First we should move it to one of the Lagrange points - forget O'Neill cylinders.  With such low gravity, flight will be natural.  What a wonderful space port it will make.

Wow.  Dusty plasma puts everything else to shame.  Everyone is talking about lightsail/magsail hybrids - and fair enough - but you can also make the insanely large mirrors and lenses required for terraforming and power beaming - including interstellar power beaming.  I may actually witness the arrival of an interstellar probe at Alpha Centauri in my lifetime.  8)

Here is a Feb 2002 presentation on dusty magsails ...

http://bex.nsstc.uah.edu/RbS/HTML/STAIF02/img0.htm

A 30 km dusty magsail with a 100 kg payload is predicted to achieve a constant acceleration of 2% of g.  That's 36 days to Mars. 

For propulsion, you need a dusty plasma ring rather than a bubble or lens.  They'll look like the rings of Saturn when operational.

Here is an April 2004 detailed NASA study on the concept ...

http://dosxx.colorado.edu/~delamere/NAS … 213143.pdf

The report says Winglee is too optimistic about the pure magsail - something happens at the 25 km mark that Winglee doesn't take into account.  But it says a 1 km dusty magsail has the same performance as a 100 km pure magsail and recommends further study.  No kidding!

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No, this is right.  There are really two things going on.  The first is absorbing incoming light from the sun ...

You can see the solar spectrum runs from about 0.2 to 3.0 microns with a peak around 0.5 microns.  Visible light is from about 0.4 to 0.7 microns (depending on how good your eyes are    Mars gets less than Earth, but the curve is the same shape.  Albedo determines how much of this incoming light gets reflected.  The albedo of Mars is about 0.25 meaning 25% of the incident energy is reflected and 75% is absorbed (vs. 0.30 for Earth which has clouds).

However, as soon as the energy is absorbed, it starts getting re-radiated as infrared energy ...

You can see that, for Mars, re-radiation occurs at wavelengths greater than 6 microns with a peak near 20 microns - a very different spectrum, so we analyze it separately.  The above graph is from Marinova again - it shows why C3F8 is such a good greenhouse gas for Mars - it absorbs over almost the whole re-radiation spectrum.  It also shows why water vapor is so important.

With the snowball scenario, albedo would rise, but re-radiation probably wouldn't change dramatically.  You're right to say that, with enough greenhouse gases, the snow would eventually melt.  I think chat is worried that you would need so much greenhouse gas, that, once the snow did melt and the albedo dropped, then the climate would go from snowball to furnace without stopping to linger in the goldilocks zone.  However, he fails to consider that engineers eat this sort of dynamics problem for breakfast before moving on to really difficult stuff.  You have to be careful, but we'll be careful.
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karov, your post about M2P2 lead me to do some research on the topic, and ... these things are the closest thing we have to StarTrek force fields!

This 2001 paper by Winglee ...

http://www.ess.washington.edu/Space/M2P … elding.pdf

discusses using M2P2 plasma magnets up to "a few thousand kilometers" in diameter to shield interplanetary travelers from even the harshest radiation (gamma and SEP).  The reference case is a 1000 km bubble generated with 100 kW and a kilogram of helium per day.  The magnetic field is generated with a 200 mm (8 inch) electromagnet generating a field strength between 0.1 and 1.0 Tesla.  This is doable today.  The biggest difficulty is that the field has to be pulsed to avoid becoming a magsail and changing the vehicle's trajectory.

The diameter of Mars is 7800 km.  If we can do a 1000 km shield by, say, 2020,  there should be no reason we can't do a 20000+ km shield by 2050.

I wonder if plasma bubbles can be made into optical lenses and mirrors? 

Maybe focusing the solar wind through the center of a plasma toroid could be used to heat the Martian poles.

8)
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I think there is still the expectation of 300 mb of CO2 from the soil.  That alone should raise temperatures another 40 K.

But of course, we won't be depending solely on CO2, but also on long-lived super greenhouse gases like C3F8 which are tens of thousands of times more effective than CO2.

You may be right - every greenhouse plan may end in an artic deadend - lots more research is required - but I think you're underestimating how effective greenhouse gases can be.
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Remember that the boiling point of CO2 is much lower than H2O (-108 F vs. +32 F).  Zubrin estimates that just a 4 K rise in global average temperature would evaporate the Martian poles and yeild an atmospheric pressure of at least 300 mb (and maybe as high as 600 mb)

http://www.users.globalnet.co.uk/~mfogg/zubrin.htm

But the global average temperature would still be -100 F, so all H2O would still be in deep freeze - you'd still have quite a ways to go before H2O snow would become a concern.
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Just beautiful.
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That's really interesting.  The Prospector detected lots of hydrogen, but the impact didn't produce the expected plume of H2O.  The temperature in the luna shade is supposed to be around 100 K (-280 F).  That's cold, but hydrogen is still easily a gas.  I suppose they looked for methane and ammonia signatures?  I wonder what form the hydrogen is in?

For mining purposes, it doesn't really matter.  There is lots of oxygen in the luna regolith.  As long as we can get hydrogen somehow, we can make water and rocket fuel   
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The landers didn't, but the orbiters had a a near-infrared spectrometer that was called the Mars Atmospheric Water Detector (MAWD).

http://pds-geosciences.wustl.edu/missio … /mawd.html
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The moon should be terraformed to create a stable biosphere in a shallow gravity well ( = less energy to reach the rest of the solar system ).

I imagine luna terraforming to include the following steps:
(a) bringing one or more comets into low luna orbit,
(b) solar heating of luna regolith with parabolic mirrors to release 1 mb of oxygen,
(c) slowly adding to the newly formed atmosphere by breaking up the comet(s) into small enough fragments that they burn up during deorbit, and
(d) establishment of a laser roof to slow atmospheric loss.
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Actually this isn't true.  Albedo determines how much energy the surface absorbs initially, but then, without greenhouse gases to keep it in, the absorbed energy just gets re-radiated into space - pretty much as predicted for a classic black-body radiator.  Greenhouse gases change the situation enormously.
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