Terraforming Mars

[belovelife]

so if you used hydrogen peroxide in a vehicle
as the "gas"
you would still need a hydrogen fuel cell?

[harmonSmith]

interesting

[CraigD]

Originally Posted by belovelife

so if you used hydrogen peroxide in a vehicle
as the "gas"
you would still need a hydrogen fuel cell?

You could use hydrogen peroxide () to power an engine. It’s exhaust would consist mostly of hot (about 600 C) and . Though very clean, this high-temperature exhaust would react with other compounds found in air to produce some of the same pollutants (eg: nitrogen oxides) as petroleum-burning engines. Also, unreacted could be present in the exhaust. Without an effective exhaust treatment system, an powered vehicle would, I suspect, be pretty hazardous to anyone breathing in its vicinity. “High test” (that is, concentrated enough to react to do work) is also scary stuff to handle, as it reacts violently with such materials as human skin, and if it comes into uncontrolled contact with materials it could easily be spilled on, can react violently enough to be considered explosive.

In short, it needs to be handled much more carefully than gasoline or diesel, and is only potentially environmentally cleaner.

Hydrogen peroxide also has a low energy density (about 2.7 MJ/kg) compared to fuels such as gasoline (46.4) or hydrogen (143). This is due in part to it containing its own oxidizer, where these other fuels get oxygen from the air, 2.7 MJ/kg is a pretty low energy density for applications like autos, closer to that obtainable from good batteries than from ordinary fuels.

In short, hydrogen peroxide doesn’t seem a good alternative car/truck/airplane fuel.

Hydrogen fuel cell exhaust is almost nothing but , making it almost certainly the cleanest power source available - you actually can, and Apollo astronauts did, drink its condensed exhaust water! However, they remain terribly expensive to make and easy to ruin, while compressed gas or liquid hydrogen is difficult and expensive to handle - simply keeping it from escaping before it can be used is a challenge.

In short, despite optimistic projections from policy makers and auto manufacturers, the feasibility of fuel-cell powered cars is far from assured.

[Moontanman]

I used to fly model rockets powered by liquid freon, the vapor pressure was used to make a reaction rocket. I've often thought that a H2O2 powered rocket would be pretty cool, built along the same lines as the freon rocket. The mono propellant H2O2 does need a catalyst, platinum I think, in the nozzel, does anyone know how much thrust to weight the peroxide would provide compared to a freon type rocket or a solid fuel model rocket?

[CraigD]

Originally Posted by Moontanman

does anyone know how much thrust to weight the peroxide would provide compared to a freon type rocket or a solid fuel model rocket?

According to reports from companies building them (see previous wikipedia links) bipropellant rockets have specific impulse slightly less , and slightly better than kerosene. As a monopropellant, has about half the energy density of bipropellant. The best solid fuel rockets have about half the of liquid fuel ones, so as a rough guess, I’d say peroxide monopropellant would be roughly comparable to solid fuel.

and energy density aren’t the same as thrust to weight, but for rough comparisons, I think they're OK.

The energy density of peroxide monopropellant is about 5 times greater than the best compressed gas, so it would, I think, blow away all your Freon rockets (hopefully not literally ).

[Eclipse Now]

Hi all,
I'm loving this thread but just had to respond to something back on page 4. Will continue with the Mars stuff after this rant.

Originally Posted by dcmike

TO Chief Seattle:
What went wrong Chief Seattle? Religion and overpopulated cities ("civilization") went wrong, and took everyone with it. People in cities have more opportunity to find mates, so they overpopulated and expanded to other areas. They were forbidden by their religion to control population by any means but war. As they crossed the oceans and landed on other people's homelands their cross was held high and millions fell beneath it. When you believe your religion makes you superior to all others you can denigrate the "unclean" and treat them as less than human - with sanctity. No guilt was felt because "God was on their side". Americans still worship this same god, never asking if he was immature then and has grown wiser now. It is still believed he was and is perfect.

Pffft, do bacteria suffer from "religion"? Or the deer on St Matthew Island?
http://dieoff.org/page80.htm



It seems Agent Smith was wrong. Man is not a virus because he grows and grows until his environment is destroyed, other mammals also occasionally reach a certain "saturation" of their environment and then destroy it. Indeed, I would say that all individual species primed with the right growth conditions would grow until they exhausted their nutrients and then experience "dieoff"... it's just that sometimes nature finds an optimal mode of species interaction, called the food web, that enables certain energy flows. In a certain balance we call it an ecosystem.

In an artificial environment, we call it a petri dish. In our case, with our bigger brains, we call it "over-consumption" or "environmental degradation" but it's not necessarily involved with religion. I know atheists with enormous families and religious couples with no kids.

[belovelife]

ok so thi is salt water@-75degrees f

and it moves up
very strange

(from the mars pheonix lander)

[Eclipse Now]

To the Moderators, can this thread please be split at the Panspermia leap-off point, and we continue discussing Mars? Please? If there's another post on viruses falling from the sky or epistemology (how we know stuff for sure) I might just turn on "Invasion of the body Snatchers" out of spite.

Please let us know soon, as I'd love to ask some Mars questions. Cheers.

[Eclipse Now]

Would a "thick enough" atmosphere protect us from the solar radiation on Mars?

[Moontanman]

Originally Posted by Eclipse Now

Would a "thick enough" atmosphere protect us from the solar radiation on Mars?

Yes, our own magnetic field does indeed protect us from radiation but it's role in stopping our atmosphere from sputtering off into space is more important. Our own atmosphere is the equivalent to several inches of lead in stopping radiation. If we didn't have our atmosphere the really very weak terrestrial magnetic field would be better than nothing but it wouldn't protect us from high energy cosmic rays and other very energetic radiation from space, nor would it protect us from things like X-rays, UV, or Gamma rays. These forms of radiation would end life on Earth just as surely as the charged particles from the Sun. Venus, which has no significant magnetic field, is a case in point, it's atmosphere, mostly CO2, is around 1300 psi or 90 times Earth atmospheric pressure. If the Earth's CO2 were released we would have just as much CO2 but many times as much water as Venus. lack of a magnetic field allows the suns energetic particles to strip away the hydrogen from water and from Venus and leaves Venus bereft of hydrogen which would mean no life even if there was lots of atmosphere.