New Mars Forums

Well, if the only flammable things on Mars are our farms and colonists, then that's what'll burn.

Of course, we could plant forests and tundra (?) so the rising O2 concentrations would have something else to burn than our farms and colonists...kind of like providing false targets...

Figuring out a way to infuse good amounts of buffer gas would pretty much solve all of those problems though. All of those problems more or less just mean, "insufficient buffer gas". That's all it comes down to in the end. We need buffer gas.

Nickname, you are absolutely right that we should not ignore the CO2 toxicity.

I think most people are just hoping we'll get huge amounts of oxygen and buffer gas from...somewhere, I dunno, I guess they're thinking of bombarding Mars with asteroids or something.

For humans, building up the pressure is enough, it can be all CO2 if that's what it takes -- we can wear breathing masks if so.

But plants can't wear breathing masks, so if we want to open sky farm on Mars, we'll have to have a lot more gases in the atmosphere than just CO2.

Of course, we could always closed dome farm.

CO2 has a molar mass of 44, versus O2 of 32 and N2 of 28. So it's not so much heavier that some of it couldn't be thrown higher up in the air by currents.

SF6, conversely, has a molar mass of 146...which is pretty drastically different from all of the above.

I'm not saying it wouldn't leak at all -- in an open crater, everything would eventually leak -- but I think it would be a really slow process, especially if you only, say, half filled the crater to 4.5km and let the top half be CO2. The SF6 would have to work its way 4.5km up through the much lighter CO2.

I agree that political correctness and playing it safe have killed mankind's adventuring spirit sometime in the last 50 years. I know I'm going to take a lot of heat for this, but if people dying is what it takes to get us into space, then by all means, blow those people up. I do not regret the people who died in Challenger and Columbia. People *will die* if we want to get into space. Pioneering a new frontier should never be safe, and if it is, then you're just doing it wrong. Look at all the people who died in colonizing the Americas. A new frontier is pretty much unsafe *by definition*, almost. Sure, you can check and double-check and triple-check and quadruple-check everything and have a thousand redundancies to get a near 100% success rate. But by that time, you'll be putting so many man-hours into safety that the program will grind to a halt under all the safety measures.

That's what we've seen in recent decades. We've become so obsessed with safety, afraid of taking risks, that we can't do anything useful anymore. Fear of Challenger and Columbia repeats has more or less paralyzed America's space program.

We're not going to get anywhere by playing it safe. Any person who plays games of chance will tell you that if you take low risks, the rewards will be equally low.

If we want to spend the next 50 years expanding the ISS by 50%, whoop-de-doo. If we want to do anything *meaningful*, we will have to lower safety standards, take bigger risks, blow people up, and get somewhere.

That's my view anyway.

As somebody who considers himself very liberal and very democratic, and for whom a candicate's space policy is one of the top three reasons to vote for them, I find your characterization inaccurate scapegoating. You're just trying to shift blame on "the other side".

There are just as many ku klux klan rednecks down south who couldn't give a damn about going to space, just about hunting down them thar blackies and seein' em hang.

If we want to mudsling pointless stereotypes, that is.

Don't try to make this into some make-believe "republicans are pro-space and democrats are anti-space". If that were true, why would Bush (a republican of the worst kind) be against NASA funding increases?

Space is something that attracts both right-wingers and left-wingers alike. It isn't political parties that split us apart, but rather, it is something that *unifies* both parties. In this day and age of a split America, we should highly value any such things that are common ground and of interest to both sides.

Oh, absolutely, but I'm not asking for *knowledge*, I'm just providing a springboard for some fun speculation.

Speculate, go nuts.

Humor this hypothesis:

What if a human being's optimal living conditions are *not* terrestrial?

In that case, what would be our optimal living conditions?

Gravity: Is 1g optimal for humans? Wouldn't higher gs produce more stress and strain, and thus automatically produce a workout for everybody during the day? For example, 1.1 or 1.2g -- would an environment like that produce a "Bold and the Beautiful" civilization where everybody is in perfect physical shape? Wouldn't higher gs, with their musculature-enhancing effects, lower heart disease and other diseases of sedentary life? And if so, what would be the optimum? A 5g planet is probably too much, a 1g planet too little -- what might we humans want, for a good steady constant workout, but not to a damaging degree?

Pressure: Is 1bar optimal for humans? A lot of athletes train at higher altitudes in order to improve the oxygen processing rates of their blood. An athlete who acclimated to high altitudes can run faster, for longer, than their higher-pressure brethren. Might the optimal air pressure for humans be something other than 1bar? On the other hand, the athletes only receive their advantage when they come out of that low-pressure area into the high-pressure area. If the entire environment available is low-pressure, does that give any long-term benefits -- or even the opposite, does it damage us? Do high-altitude communities have lower scholastic performance or better?

Temperature: There's little arguing that 15-20C is pretty ideal for humans. But most environments on Earth receive a lot of fluctuation, both diurnal and seasonal. Would an environment that stays at a *constant* 15-20C (through whatever means) be better for humans, or are the fluctuations necessary to us?

Other aspects: (please add others)

Sum all of these together:

What is our optimal living planet?

So to put it concisely, if an area was pumped 100% full of water vapor and there was nothing else in the area, the gaseous H2O would automatically condense until only 35mmhg remained gaseous? No matter the ratios of H20/available volume? It would always gravitate, in any volume available, to 35mmhg of gas and the rest as water?

Mars will never be as good, simply because of its lower gravity.

If we ever develop technology on the level that you suggest (moving around dozens of bars of gases), Venus will be a paradise planet. Removing its extra gases will make it a much better planet than adding gases to Mars.

Target values:

m = 100 000 kg
a = 0.00981 m/s/s (milligravity, one thousandth of a g)
t = 5 years (after halfway point, you have to start accelerating in the opposite direction so you won't overshoot your destination) = 158E6 seconds
v(peak) = a*t = 1.5E6 m/s = 0.5% of c (0.005c) velocity at the 5 year mark
E(peak) = 0.5mv^2 = 120E15 Joules expended to get to the halfway point
P = E/t = 759E6 W
v(average) = 0.5v(peak) = 774 000 m/s average speed for the whole trip
x(total) = v(average)*2t = 244E12 m ~ 1630 AU ~ 0.03 light years

So assuming 100% efficiencies all around (theoretical maximum) a 760MW power plant could accelerate a 100 ton ship at milligravity (1/1000g) for 10 years, getting 0.03 light years away in that time.

1/100g would require 76GW of power, would reach a peak of 0.05c at the five year mark, and would get 0.3 ly away.

1/10g would require 7.6TW of power, would reach a peak of 0.5c at the five year mark (relativity effects not included), and would get 2.6 ly away in those 10 years.

Unless we discover an antimatter mine in the inner solar system, TW ain't gonna happen. Even 76GW is unlikely.

760MW though, I could see as a space power plant one day.

And you can preserve them perfectly well regardless of what the Chinese do. Their colonization efforts in no way weaken ours.