New Mars Forums

Sorry, even if the scale is lower, efficiency can only be reached through steel. Steel is tougher than bamboo, Steel is more shock-resistant than Fiber-glass or other fibers for composites. Fiber-glass is generally not very strong. Kevlar & carbon fibers are very tough to make, even here on earth(IIRC, only japanese know how to make carbon fiber).

And you have yet to prove there was enough volcanic activity on Mars to have provided the planet with interesting veins. That's why exploration missions are essential. 500 days, not 30 days. To find out what's really there & what can be done. Only once you've got a proper picture, you can accurately plan for settlement.

And there is another problem : while the colony works on exports, it does not work on self-improvement. As GW said, everything has to be built there : atmosphere, soil, water supply. Better focus on them than on random exports. Would be sad to see the colony lost due to excessive effort made into exports. That's one of the things that killed Norwegian settlements in Groenland - too much effort in capturing live polar bears & falcons, not enough on stabilizing wood supply & other essentials(cliamte change also was deadly to them).

El_slapper. Real facts are stubborn : it will be tough.

I think I have to side on Impaler's side, on this one. For mechanical elements, there's a lower limit of price. Prices of cars or planes are showing stagnation since decades. Prices of launches are falling down strongly those days, because they are still faaaar above that minimum cost(and high prices/costs had no incentive to go down until recently). Yet, we will meet a limit, sooner or later.

Even more for machining. I know there's been impressive things done with dynamic extrusion. Yet, it's not enough to build an industrial base. You need good steel, good tools, and good power. Solar power, despite its qualities, lacks punch - especially so far from the sun. Nuclear power has other problems.

For scaling up, you need a lot of steel. Why? Let's begin by the beginning. Scaling up population means scaling up housing & food production(and other things, that I will consider minor even if they are not). For housing & greenhouses you need a lot of transformed materials. For them yuo need a lot of raw materials plus a lot of machining & other transformations.

For getting a lot of raw materials you need mining. Mining does not scale down well. The ground is hard, and only big machines with a lot of strong steel using a lot of power can manage it decently. You won't get anywhere with medieval-style pikes & shovels.

For transforming all that into high-quality finished elements, you need machine tools. For wich, usuallt, quality comes with size. An heavier, bigger machine suffers less from vibrations, is more rigid, and will overall machine more accurately. More power also meansmore speed(and speed control), & therefore ability to have better surface conditions. Surface conditions are very important in a planet that will not yet be terraformed.

el_slapper. I'm imitating Rune, now. But I know when not to be too optimistic.

waow. That's the kind of things I'm not equipped to understand. I just want to know if I read it right : 40 million metric tons of atomic bombs?

el_slapper. You Rune & GW Johnson are really tough guys.

Louis, for most airplane crashes, 'chutes would not have saved the day. The most frequent scenarii are

_failed take-off(Concorde, Gonesse, 2001, less than 10 km from my home) : you are not high enough for a 'chute to save you.
_failed landing : everything is OK, you're going to the track, and crash.
_unexpected crash where you thought you could go, and in fact that damn mountain was higher.
_misinterpretation of the instruments(Rio-Paris crash in 2009, where even the crew did understand far too late that the ariplane was losing altitude quickly. Last sentences were "
_I don't believe it, we're gonna hit!
_I don't understand, what's happening?")

The only case where it could be useful would be a complete engine shut-off, with no engine recovery possible, above the ground. That's not a common scenario. There are 'chutes on military aircraft because they all share another scenario : shot down by the enemy. Scenario where 'chutes can save your life 50% of the time. Scenario that airliners are not supposed to share.

Spacecrafts, at least in the beginning, will be far smaller & less reliable. 'chutes there will be far more useful in case of failure, & failures will happen far more often. When I took this A320 to come back from Krakow 10 days ago, we were more than 100 inside. Giving 'chutes to more than 100 people, then having them jump from a limited number of doors, without getting eaten by the reactors? Well, better try to survive the crash.

That's my point : they are not necessary. Those guys think they are, don't know them well, and therefore make unrealistic plans for using them. I therefore think their credibility on other topics is limited.

Ice I fear for life zones. It melts. But you are globally right : there must be plenty of other solutions. Just polymers might be not the best idea, especially in the beginning, with a small industrial base.

Beaten by GW, quicker than me(like often). Energy is costly(especially on Mars), and Rails reduce a lot fuel consuption. The global energy use of a truck on earth is 11 times bigger than the one of a train(France, 2005). Remove air drag on both(as air drag will be very low on Mars), and the difference is even bigger.

Though rails will also need energy to be built. Kind of investment. seems very worthwile to me between points of interests & central bases.

Do we have experience about high-effort management in space suits? I mean, once on a bicycle, one could push itself strong, with a lot of sweat & breath. I ask, as I have no clue. While working on ISS does not seem simple, the difficulty seems not to be physical effort. On Mars, il will be(biking, shoveling.....)

Nope.

Cast Basalt is 1/1000 mechanical resistance of basalt fiber. I know lower gravity means lower mechanical constraints, but not to that point. Even for the sleeper/tie, it would be damaged far too easily.

About the rail vs road debate, don't forget that the rail allows bette usage of energy. Friction is lower. If you are to rely on relatively low-punch solar energy, then rails might be mandatory.

Here on earth, the rail vs road debate is about cost of infrastructure vs cost of exploitation. But there is more : the biggest ground transports can be made only by rail. And costs can be strongly reduced by the use of narrow gauge

Seen from the other side of the atlantic, seems like Obama does not care, & republicans are even worse. Newt being the exception(but his projections seem, huh, like promising laser swords & hyper travel within 20 years).

At least, your presidential candidates speak about space. None here in France did. Their only obsession is wether sales tax should go up by 1.6%(Sarkozy) or 1.8%(Hollande). Space exploration is for low-level sub-ministers. And that's France, main engine for space exploration in Europe.

Composites are not just matrix + cloth. They usually imply some chemical coating of the cloth, so that there is some "gluing" of the matrix & the cloth. If not, you end up with micro-bubbles everywhere, and those are a pre-made damage to your structural integrity.

Infos about ice+basalt composite on google is no existant. Probably because here on earth it makes no sense, & noone ever tried. On Mars it could work, but a lot of work is needed so that you ensure the matrix is glued to the cloth. No need for a strong link : just enough to weed bubbles.

The "concrete" you speak about is a different kind of things. Pre-tensed concrete is not a "composite", in the sense that you have no glue between concrete & steel(on earth), & it does not matter. In terms of mechanical resistance, you have concrete with holes, & sticks in those holes, with a mechanical push inwards from both sides of the concrete.

Therefore, your idea hols potential - no more need for a "glue". OTOH, you have to make the "regolith icy concrete" have some mechanical properties by itself. Not much, but enough, especially in compression resistance. Pre-tension makes sense only on compression-strong, traction-weak materials(as, you guessed it, concrete). If your regolith-ice mix behaves the same(but I have no clue about it), then it would be an elegant  & efficient solution. If...

A composite with fibers of itself? That's ..... mind-bending. It probably won't work because fibers will simply smelt into the matrix, and mix with them. And it's probably useless, as if you already have the strength of basalt as a whole, then basalt-fiber won't help.

For what use did you have this idea in mind? I don't thow your idea right now in the bin, but I cannot see how it could be useful(or done).

We will need machining capabilities. Most spare pieces of mechanical tools can't be cast, or hand-made, or whatever. They can be only machined. It's mandatory for surface quality.

Then why do you need such a complicated way for doing the model? Just take some metal(probably steel, maybe something lighter if available), machine it as accurately as possible, and use it as a model. If the model is too complicated for being made in 1 piece, assemble several machined pieces together with rivets/screws/whatever. Then cast.

If your first model is not accurate, you'll have to deal with variations of thickness of your thermoset. That's no good news. When cooling, the whole thing will have a set of strange, unwanted behaviours. And if your first model is accurate, you don't need a second one.

Or then there you can use a 3D printer. Your model can be absolute crap in terms of mechanical properties, as long as you can put your sand around. Hell, even if Louis's link is not as promising as it sounds, I've maybe found a usefulness to those not-that-wonderful machines.