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Ultimately, we can state with confidence a conservative lower estimate of 120 mbar for the limit of safe CO2 partial pressure. This raises the possibility that CO2 might actually be used as a significant buffer gas in terraformation.

I personally have a favorite type of UV protection on mars.  It is called sunscreen.  More precicely, Homosalate, octinoxate, octisalate, oxybenzone.

http://en.wikipedia.org/wiki/Homosalate
etc.

or more generally:
http://en.wikipedia.org/wiki/Sunscreen# … ngredients

just puttinga coating of any of these on the dome fabric would allow it to be very protective.

A mesh of rubber/plastic pipes that are filled with high pressure water? The water will keep the dome stiff and provide radiation protection. Wait, Bigelows probably thought of that for inflatable spacecraft.

How cool is that.

However, even at 200 mBar, we should be able to enjoy lakes that freeze during winter. Many (most?) species of cyanobacteria are not killed by a winter freeze so we should be able to get a biosphere started in small areas quite early.

MarsRefresh wrote:

A good idea dies hard. Very Happy

So the 1/2 bar pressure will require thousands of years in the above scenario. Obviously that's a long time. Have you detailed how much/many iceteroids your scenario has introduced?

Rick wrote:

Now we need to increase the current N2 pressure by about 28 times. I am assuming that half of this comes by H-Bombs in deep rock deposits. I am assuming that for every tonne of nitrogen brought by iceteroid an extra tonne of nitrates are volatilized by the impact. So we would need to increase Mars' nitrogen level by 7 times via direct importation. (This would be 240 impacts of the 2.6 km bodies described above.)

This is from the post near the top of this thread where I'm trying to increase the N2 partial pressure to the point where nitrogen fixing bacteria have enough N2 in the air to fix.

Note that if you halve the radius, you increase by ~8 times the number of asteroids that you need to move. (Of course each asteroid is 8 times easier to move...) Large impacts blow away bits of atmosphere, where as small impacts blow away zero to an insignificant amount of air. So I generally suggest we move lots of smaller bodies than a couple big ones.

An Aerial Ropeway is the connection by ropes (wires, cables etc) between   
at least two terminals (to load and unload). The cars can be fixed or temporary coupled and be moved either by the running rope, or by the motorized car itself. There are many different solutions. 
 
Thethered High Altitude Platforms up to 20 km and more have been studied and found feasible. Thether samples were built and tested to 100.000 lbf breakstrength. The mentioned Carbon Nano Tube rope technology is today still experimental (max. length 20 cm!).
   
Yes, the whole system can be operated by solar power, because of its low energy needs to move the cars on the rope mainly in the flat plains. The towers at the terminals will be constructed to hold big parabolic mirrors to concentrate solar radiation onto sterling engines (generators). 

In the long range exploration on Mars the power will be supplied by big generators, landed sometime before the first crew will arrive. For safety reasons the landing sites will be miles distant. Though you need some robots to connect the (heavy) power cables to the habitat.
These robots can be instructed to install the aerial ropeways. Actually the power cables put between supporting pylons could be used as an Aerial ropeway. 

The important point of aerial ropeways is they are movable without loss of material. In mountain areas they are temporalily installed for taking out the cut trees (logs).

These robots can be instructed to install the aerial ropeways.

After pouring back through the old posts, it seems that Robert Dyck's proposal of PCTFE for greenhouse material is the best bet. But it still seems than a PCTFE greenhouse would get cooked by UV radiation. The UV coatings are metals and eliminate the transparency for visible light as well. Am I correct in this? Are there any plastics which block UV, while allowing visible and infrared? It sounds like Kevlar does, but in so doing it breaks down rapidly.

If not, does anyone have information on the UV resistance of glass?

why worry about that? why not just ship over bulbs for planting... its prooven to work, so why not use it? besides you can keep the plants on any kind of schedule you want then instead of a specific one. mars based. and as for the exterior paneling you can use what ever you want instead of a transparent one.

Spectrally Selective low-e glazing can the most dramatic protection for UV and IR. By trapping InfraRed light in, radiative heat is kept in. IR is radiant heat. According to the graph to the right, spectrally selective transmits 82% of violet light, 85% of blue and green, but 45% of orange and 30% of red.

But I think that a fairly modest effort would allow us to crash it. If we could get to it 6 months earlier we would need a lot less effort. (e.g a magnetic sail with a few dozens of Newtons of thrust for 6 months may be enough.)

As of 1 January 2008, 5,118 NEO's have been discovered: 65 near-Earth comets(NEC) and 5,053 near-Earth asteroids(NEAs). Of those there are 427 Aten asteroids, 1,947 Amor asteroids, and 2,671 Apollo asteroids[3]. As of 4 January 2008 there are 165 NEAs on Impact Risk page of NASA website[4]. But none of those NEAs is placed even in 'yellow zone' (Torino Scale 2) meaning that none of those asteroids warrant attention of general public.[5] There are 905 NEO's which are classified as potentially hazardous asteroids. Currently, 136 PHA's and 731 NEA's have an absolute magnitude of 17.75 (effective from 30 November 2006 as per NASA website[6]) or brighter, which roughly corresponds to at least 1 km in size.

What about just melting the rocks and dust so it would solidify into a road?

i'm curious if lightning has the same effect on the materials there in their dirt/sand like ours does where it turns into a glass sheet... if so i already have an idea of how to melt the roads easily

I am curious to see your "polished" proposal for melting roads. 

Dragoneye wrote:

wrote:

and as far as a rover driving through those storms... i doubt it... do some research on how intense those storms get... immagine a big huricane in the southeastern section of the US... thats what they essentially are... thats why i am suggesting such big precautions.

Well, the highest recorded wind speeds I found were 250 mph, and these were in the upper atmosphere, screaming off the poles in the Spring. If we design for 200 mph surface winds that should be plenty, I think. However, currently the Martian atmosphere is less than 1% as dense as Earth's and so has that much less punch. On the other hand, things weigh 2/3rds less.

When analyzing the potential of windmills on Mars, Zubrin calculates that a 60 mph (30 m/s) wind would generate the equivalent force of a 12 mph (6 m/s) wind on Earth. This is a ratio of 5 to 1. Therefore a 200 mph wind on Mars would be roughly equivalent to a 40 mph wind on Earth.

My conclusion is that the equivalent of a 40 mph terrestrial windstorm would pose less of a threat to a surface rover than the darkness of heavy dust conditions. BUT, this is true while the atmosphere is at 1 millibar. If we double the atmospheric pressure than this would dramatically increase the power of the wind. (Would it exactly double?) So, I think your idea of sequestered roads are increasingly relevent as terraforming progresses.

The most likely scenario for a future Mars society will be a combination of various road and railroad structures. The Dragoneye Iron Roads would first be built in high priority routes, say between two close bases. However, unless it's much easier to build these roads than I expect, the raised roadbeds would be an important component of the transportation network and simple jeep tracks would still have value for low priority pathways.

Hmm. I wonder if canals would be feasible? Perhaps a long 1-2 mm thick polyethylene tube 10 m (or even 5 m?) in diameter could be laid over long flat surfaces such as the northern plains and covered with a a thin layer of soil. Fill it 1/3 to 1/2 full of water and send narrow barges through, one direction at a time. Ships on Mars would have a ridiculously shallow draft and the barges could carry suprisingly large amounts of cargo. Water transport is by far the cheapest transport method on Earth. Anything that can go by ship goes by ship.

as far as the water transportation... its super cheap here on earth because the "ground work" is already done... and you dont need to do anything to get it going just have a ship drive it there on water... to get water there you would neeed to melt ice caps on the planet... I wouldn't do that seeing as water is a HIGHLY valuable comodity....

it would be cheaper i think to "melt" cheap tracks or guides to be able to drive things arround... and since we dont have to worry about power since i have that part figured out (literally we dont need to worry about power)

the biggest thing we need to do there on the planet is get plant life introduced, and get water to water them.... once we do that we can derive plastics and other resources we can use to build and construct things there with so we aren't dependent on long durration trips from earth for supplies... I really do think that a major requirement for us to be getting to mars and sticking arround there for some time we need robots to help do lots of things for us...

I know i'm getting off topic with roads... but roads are all stemed off other things.... i dont feel exploration of the planet is our biggest thing off the bat.. and to do that we would be getting off focus.. our biggest thing is establishing a presence there.

I agree that a sustained presence is essential. Once we get permanent colonists on Mars there is no going back.

You're probably right about my water canals idea. It's attractive only if we get substantial quantities of water from the ground or ice caps (although nothing like a sizable chuck of either would be needed). The reduced gravity would make everything quite bouyant too.

Your comment on not worrying about power has me curious. Is your company about to announce the development of mobile fusion power plants?