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#126 2020-02-10 22:19:07

tahanson43206
Member
Registered: 2018-04-27
Posts: 2,828

Re: Power Distribution by pipelines on Mars.

For Louis re #124

Thanks for picking up on the question I've posed.

You've asked an interesting question, and (at this point) I don't know the answer.

Your question assumes that a ski moving across a layer of ice will cause it to melt.

We humans have several centuries experience moving objects across ice.

During winter on Earth, lakes and rivers in Canada freeze over, and truck traffic carries great quantities of material over the frozen surfaces.

It seems worth investigating to see if a layer of ice (water or carbon dioxide) can be maintained in tunnels under the Martian surface. If they can, and if any heating caused by traffic can be removed by dissipating that heating into the Martian regolith around the pipe, then the speed of transit should be quite high. 

The principle of operation of Elon Musk's Hyperloop is to move pods through evacuated tunnels, so a Martian atmosphere might well qualify as "evacuated" for transportation purposes. Relatively little energy would (presumably) be needed to keep pods moving along an ice layer inside a tunnel, and that could be provided by overhead magnetic fields.

Another advantage of an ice layer transport system is that the engineering crew does not need to worry about keeping the pipe perfectly level for its entire length, as would be the case for a water borne transport system.  A bit more energy would be required to move a pod up a modest incline, but then less energy would be required to move it on the down trending incline.

I notice this topic is about Power Distribution and not about Transportation of Goods by pipelines on Mars.

It might be time for someone to start a new topic to allow for continued development of this branch, while the original is allowed to continue developing along its original path.

Edit#1: A quick Google search seems to support the supposition that no measurements of temperature under the surface of Mars have been carried out. The most recent lander included a temperature probe, but it was driven only a short distance under the surface.

The most recent report I found was from October of 2019, and the heat probe was still at the surface, so it would appear we humans have no direct knowledge of temperatures under the surface.

Thus, we have no way of knowing if temperatures under the surface are low enough all year long to support an ice based transport system. 

Edit#2: The article at the link below provides a short introduction to the mechanics of ski interaction with snow.  It discusses the effect of pressure on snow, melting to water and then freezing to ice.

http://www.mechanicsofsport.com/skiing/ … s/why.html

Edit#3: This is primarily for Lewis, in (partial) answer to your question about a ski melting ice.

https://www.forbes.com/sites/chadorzel/ … 1fc41f4973

The author appears to have investigated the physics of sliding on ice to some depth.  I was interested to learn that although melting does occur when a ski interacts with a layer of ice, the temperature drop is only (about) 1 degree.  Sliding is still observed in arctic expeditions with temperatures of -40. The key take-away for me is the idea that there exists a state of water at the boundary between ice and atmosphere which is disordered, and allows or enables low friction interaction of the ice with a surface such as that of a ski.

I am coming away from this preliminary investigation thinking that there may be a range of temperature of an ice passage that would be optimum for ski transport on the Earth or on Mars.

The freezing temperature of carbon dioxide is so much lower that that of water that I find it difficult to imagine a transportation tunnel based upon dry ice is practical for Mars, but perhaps there are some permanently cold regions where the physics of sliding on dry ice would be favorable for transportation.

Edit#4: Here is some actual research done with dry ice.  The focus is a question: Could blocks of dry ice be making tracks on Mars.

The answer is (apparently) that is possible, but since the experiments were done on Earth, they are not conclusive.

https://www.scientificamerican.com/arti … n-gullies/

What I'm picking up from the article is the idea that the direct sublimation of dry ice may provide a frictionless surface, since the support material is a gas rather than a liquid.

Research would be needed to discover if there is a combination of dry ice and sled material, and temperature of the environment, that favors low friction sliding of a transport pod.

A warning appeared on a nine year old thread about skiing on dry ice, that a ski made of "normal" material might simply freeze to the dry ice. However, I took that as mere speculation, since the thread itself appeared to be of a lighthearted bantering nature.

(th)

Last edited by tahanson43206 (2020-02-10 23:46:27)

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#127 2020-02-11 16:53:35

SpaceNut
Administrator
From: New Hampshire
Registered: 2004-07-22
Posts: 18,863

Re: Power Distribution by pipelines on Mars.

The energy of mars, gasses and so much more are being transport and with the purposes brodened to include people not just goods we are looking at the means to connect all of the my Hacienda to gether.

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