Topic: How mirrors could change mars... at least a patch of it...

[Tus-XC]

http://space.newscientist.com/article.ns?id=dn10573&feedId=online-news_rss20


Space mirrors could create Earth-like haven on Mars
20:22 14 November 2006
NewScientist.com news service
David Shiga

Mirrors in orbit around Mars could create Earth-like conditions on a small patch of the planet's surface, according to a NASA-funded study. The extra sunlight would provide warmth and solar power for human explorers, but some experts say the mirrors may be hard to deploy.

Scientists and science-fiction authors have long dreamed of turning Mars into a more Earth-like planet for future human colonists. The process, called terraforming, involves thickening Mars's atmosphere and increasing its temperature. But schemes to transform the entire planet would take centuries and would require enormous resources.

Now, Rigel Woida, an engineering student at Arizona State University in Tucson, US, is investigating the possibility of "terraforming" just a small patch of the planet's surface by focusing sunlight on it from orbiting mirrors.

He received $9000 to study the idea from the NASA Institute for Advanced Concepts (NIAC) in Atlanta, Georgia, US.

The concept calls for 300 reflective balloons, each 150 metres across, arranged side-by-side to create a 1.5-kilometre-wide mirror in orbit around Mars.

Balmy conditions
The mirror would focus sunlight onto a 1-kilometre-wide patch of Mars's surface. This would raise the temperature in this patch to a balmy 20° Celsius (68° Fahrenheit) from Mars's typical surface temperature of between -140° C and -60° C (-220° and -76° F).

The extra warmth would mean the astronauts would not need heavily insulated suits or living quarters, allowing them to work more easily. The extra sunlight would also boost power from solar cells.

And the higher temperature would melt any water ice on the ground. This could make precious liquid water available for astronauts to drink, and the water could also be used as a raw material to produce rocket fuel for the journey home, Woida says.

"The greatest hold-up to exploration, terraforming and colonisation of Mars is the lack of available materials," he told New Scientist.

He says astronauts could maximise the amount of available water by warming up a region that includes a frozen lake, such as the one near the planet's north pole that was imaged by Europe's Mars Express spacecraft (see Frozen lake shines bright in Martian crater ).

Dangerous radiation
Margarita Marinova of Caltech in Pasadena, US, who is not involved in the study, says the extra solar power would greatly benefit future Mars missions. "This would be quite useful for many types of missions – both robotic and human," she told New Scientist.

She cautions, however, that deploying objects in space can be challenging, citing an experimental tether that broke during deployment from the space shuttle in 1996 and the failure of solar sail experiments. The orbiting mirror for Mars "is not an easy project by any means", she says.

Woida points out another potential problem. If not carefully designed, the mirrors could focus harmful high-frequency radiation like gamma rays onto the surface.

Mars's thinner atmosphere would not filter these out like Earth's does, so the balloons would have to be coated with materials that would reflect only visible and infrared light, he says.

In his concept study, Woida will work out the structural details of the balloons and study how much extra light from the reflectors reaches the Martian surface.

[RazalYllib]

Many moons ago...when I was a teenybopper iirc, I came accross a paper on ideas on terraforming mars. One interesting and EASY thing to do to get the ball rolling as it were, was to tailor lichens (genetic manipulation) to survive in those conditions. Make em very DARK and reproduce like crazy. These lichen would be augmented to derive nourishment from the chemical components in the rocks and be customized to excrete CO2 and O2. The lichen would increase mars albedo gradually as well as begin to create a dense enough athmosphere rich in CO2 to nudge the greenhouse effect. When the CO2 is rich enough, seed customized algi to convert the CO2 to O2. It would take awhile though. Smashing a decent sized comet into mars also would speed up the process.

[Nemesis]

According to some estimations there is a huge amount of CO₂ absorbed into the rocks and soil of Mars.  If the temperature was locally raised as this proposal would have it in the "hot zone" that CO₂ would come out of the rocks and into the air.  The greenhouse effect would increase and the temperature would rise on a planetary scale.  A positive feedback loop would be started, the hotter it became the more CO₂ released and the hotter it would become until all the CO₂ was freed from the rocks and soil.

It has also been proposed to put a large (100s of miles across) fresnel lens in the Mars -> Sun L1 point to focus more light onto Mars that would otherwise miss it and heat it up the same way.

[Centurus]

One of the problems though that some scientists speculate that would work against making Mars habitable for human colonization is the lack of plate techtonics on Mars.

Some scientists speculate that at one time Mars had an atmosphere extremely similar to our own and that it could have supported life, but the lack of plate techtonics eventually caused Mars' atmosphere to deteriorate.

I could be mistaken.

Just thought I'd mention this.

[Dracho]

Actually, the plate techtonics are the symptom, not the cause, IIRC.  It has to do with the cooling of the interior of Mars. 

As the iron core cooled the magnetic field subsided and eventually ceased to exist (as it is caused by the crust circling the molten iron core). 

With no magnetism to speak of, the atmosphere was swept away by the solar wind (the Aurora is caused by electrons from the sun hitting Earth's magnetic field near the poles).

[Centurus]

Possibly.  As I mentioned, I didn't know too much about how it's all involved, but I do know that the lack of plate techtonics on Mars plays a part in the planet's inability to sustain life as we know it right now.