Astronauts (or other 'nauts) could find life on Mars quite healthy Mars may be more hospitable to life - including human explorers of the future - than had been feared, according to new research using information sent back both from NASA's robot rover Curiosity and from orbiters circling the red planet. As we've previously reported, Curiosity's radiation instruments indicate that normal …
I love the way that simple water is the thing we hope most to find on a remote planet. It's amazing how much of life is geared to that little simple molecule and how much use you can get out of it.
But I do wonder about the "we can get rocket fuel from water" line. Water is hydrogen and oxygen, yes, but you need to use energy to collect and filter the water in the first place, more energy to split it apart, compress the gas into storage (into liquids, no less), huge amounts of materials to store them safely, etc. And for "rocket fuel", you need an awful lot of it to get back to Earth. So the investment of energy required to make a single return trip is HUMONGOUS and may literally take years, lakes of water, fields of solar panels and heavy metal machines and containers to make it a reality.
And then you're left with the problem that H2O is 2 H's and only 1 O, which leaves you with a lot of highly-volatile chemicals just sitting around surplus right next to a huge source of oxygen (which can be more dangerous than an equivalent amount of petrol in the case of an accident). And we probably want a lot more oxygen than we do hydrogen, if we're going to be breathing it, and fuelling from it, and whatever else with it, so that means even more venting or storage of H that we've paid a lot to get and then won't be using (and to use, we need to use O with it in some form!). Sure, we can probably capture it and burn in the native atmosphere for heating, etc. somehow but that's even more expense to get it working and just as dangerous.
I'm not saying we can't use it, but it seems a bit of a pipe dream to suggest that we'll ever use it as a method of fuelling rockets - by the time you get all the equipment to use it there, and a sufficient source of energy up and running, and the plant operational and safe, then you've already used so much "other" technology to get to that point that it's probably a waste of time to be messing about with sticking a couple of electrodes into a puddle of water for the next hundred years to fuel a return journey.
I agree, in part.
But send one with power sufficient to do the job - the cost will be enormous, the energy gotten will be unmatched, yes, but the second it goes wrong and we contribute to laying waste part of another planet will be the death of the whole thing. That's if the greenies would even let you do it ("What if it crashes on take-off?!?!?!").
Nuclear is better, but has the same economic problems in terms of getting it (and nuclear material) onto Mars safely, and maintaining it for the time necessary. If you want to get like that, you'd probably have a better case for solar on Mars (nearer the Sun = more W / sq.m.), and even quite a good case for things like geothermal, space-based microwave etc.
The fact is, the power is only the start of your problems. The infrastructure to get the power, by whatever means, and keep it going mean that it'll cost more to do than you'll ever save by using local water as rocket fuel.
'nearer the Sun' ? Is this some strange inverted Solar System you are thinking of where Mars is closer to the sun than the Earth?
Solar panels are difficult enough to manage on our nice blue ball here, but replacing dodgy solar cells with a roundtrip time of 18 months is a bit much. At least with nuclear the things don't really break. Yes there would be more engineering effort in sending over nuclear reactors rather than solar cells, but the comparitive energy density is a hugely more effective use of it.
Another benefit of it would be the excess heat generated (that is usually dissipated into rivers/lakes down here) could be used to melt the ice over there, potentially solving the liquid water problem at the same time.
Nukes are pretty much always the way to go.
"But send one with power sufficient to do the job - the cost will be enormous"
The cost of sending anything to Mars is enormous. Military grade fission reactors are surprisingly small and lightweight, incidentally... there are already a few in orbit.
the second it goes wrong and we contribute to laying waste part of another planet will be the death of the whole thing
Laying waste to what? There's no biosphere to contaminate, no living things to kill, no watercourses to poison. No humans will be walking around unprotected from the environment. There's not enough oxygen in the atmosphere to support a good fire which remains one of the best ways to spread radiatioactives into the atmosphere. There's no water-based weather cycle to damage containment structures and leach away radioactives. There's not any tectonic activity to speak of, let alone volcanic and there won't be any tsunamis there any day soon. If a meltdown did occur, the physical disaster will be largely ameliorated by bulldozing a load of regolith on it.
Practically all of the arguments (rational and otherwise) against building nuclear reactors on Earth simply do not apply on Mars.
"If you mean SNAP generators or whatever they are called now then that's a different matter."
He does not.
The former Soviet Union powered a number of its ocean surveillance radar satellites with them. Look up TOPAZ. Roughly 10Kw range.
The US's only *reactor* was the SNAP 10A (Even numbers in the SNAP programme were reactors, odd #s were RTGs like the ones on the moon). That was 500W electrical using thermocouples with about 1.9% efficiency. Re-doing it today they would be about 6% efficient. It failed after 46 days on orbit (looks like a dodgy component in a power regulator *outside* the reactor itself).
SDI looked at reactors in the 100Kw range and there is (IIRC) a low level NASA programme to do one for the Moon, Mars and orbital applications. Note a 100Kw is about 1/2 the *whole* ISS array and about the size of a pickup truck engine (depending on the level of enrichment it can be about the *weight* of a pickup truck engine).
Unlike satellites, where the fission material and the reactor (in the form of an RTG) go up together, it would well be possible to send the reactor and the fission material separately, only loading the reactor after arrival and setting up.
solar on Mars (nearer the Sun = more W / sq.m.),
FAIL, VERY, VERY UTTERLY FAIL.
Not to mention that if you breathed pure oxygen, you wouldn't last too long, we have evolved to survive in an atmosphere that is approximately 20% oxygen and 80% nitrogen. Pure oxygen is, ironically, toxic.
Last time I checked, you couldn't get nitrogen from splitting water, so unless there happens to be a ready source of ammonia (NH3) to give the same treatment to, or a supply of another 'inert' gas to use, such as helium (which would all have been lost to space for the same reason there is pretty much no helium in Earth's atmosphere) or argon (which is considerably less abundant), the whole 'air from water' bit sounds a lot like a fantasy.
I did a bit of Googling and ended up with:
"The astronauts in the Gemini and Apollo programs breathed 100 percent oxygen at reduced pressure for up to two weeks with no problems. In contrast, when 100 percent oxygen is breathed under high pressure (more than four times that of atmospheric pressure), acute oxygen poisoning can occur"
I believe in comparison, it's not an insurmountable problem to find a substitute gas for breathing given some source of oxygen.
Storing hydrogen is much easier once turned into hydrocarbons, e.g. using Fischer Tropsch process. .
Using the hydrogen as hydrocarbon fuel, you'll need similar quantities of hydrogen and oxygen as you derive from water electrolysis.
Oxygen needed for breathing and growing hydroponics should all be kept within a closed system to avoid energy and material losses, and to recover C02 needed for the FT process. As to how much energy you need over how long a period, from that it's possible work out the size of a nuclear reactor or the number of square metres of solar panel. The development of flexible solar panels may eventually result in tens of thousands of square metres of solar collector being rolled up like carpets and not needing to weigh very much, so don't write this tech off as a competitor to nuclear based on how rapidly solar thin film technology is likely to develop compared to nuclear over the next 30 years.
There's no way we could send all of what's needed for this to Mars this decade, but I wouldn't entirely write off what may become possible given appropriate developments in materials technologies and minituarised manufacturing capabilities within 20 - 30 years.
is that when it comes to spaceflight, mass is everything. Energy can come from solar or nuclear (there are no clouds or neighbours in space or indeed on Mars) but fuel (specifically reaction mass) is the real cost since every kilogram you bring with you has to be subtracted from your payload. Certainly the process would be technically complex and possibly dangerous, but what about spaceflight isn't. And yes, producing enough fuel for a return journey is likely to to take time but given the journey time to Mars it likely you'll want to stay there a few months anyway. Especially if the alternative is to stay there forever.
I'm just in the middle of reading H.G.Wells' "The First Men in the Moon". If only things were that simple. Tell the Americans that there's a possible hostile civilisation, with gold mining and technology, that may well be harbouring weapons of mass destruction, and we'd have been on Mars 40 years ago.
It would be like telling the Japanese that there were lots of strange-looking tentacle aliens up there with a good education system based primarily on female-only boarding schools. Damn, they'd be up there before ESA could put out a press release.
"But that still leaves a lot of potential for explorers to be hit by harmful radiation during solar storms and so on. Shielding materials would necessarily be heavy, and thus probably impractical to send along on an interplanetary trip."
Water is a pretty good radiation shielding material, esp. against high energy cosmic rays (compared to metals which generally emit showers of secondary particles should a cosmic ray hit them).
And it doesn't tend to become long term radioactive either.
Plus, presumably astronauts will be bringing along water in any case (what with all the drinking and so on).
which would save on special purpose shielding, certainly for a storm shelter.
Long flat tanks under the skin for general travel, then pump the water to a smaller centre shelter area with much deeper tanks when a storm is due.
Pretty standard sci-fi concept.
And if there is enough water, why not mold it into wedge-shaped blocks of ice and build igloos? Easy to construct a lot of them, after you get the block-making process going, which would probably be easy to automate. If the igloo walls are thick enough (about 1.5 meters should do it), they shield the inside completely from radiation. And there is no danger of them melting on Mars.
IIRC One of the *key* enablers in Robert Zubrin's plan (A Case for Mars) was just such a reactor., even acting as a raw heat engine to melt your way into polar ice.
Note that once your in *any* kind of atmosphere the heat sinking problems get *much* easier (even when it is about 1/1000 the pressure on Earth, there's still *something* for convection to operate with). Gravity can be quite useful too.
However as such a system would be *critical* to the whole expedition you don't want a single point of failure.
Taking 2 (ideally on separate vehicles) would be a *very* good investment.
All good things come in threes. Don't pack a 500MW nuclear reactor for your ship's powersupply and engine. Pack 3 ~175MW nuclear reactors instead. And only use the power from 2 of them in your planned trip so if one kicks the bucket, you can still make it to Mars with only a minimal change in plans.
Physically separating the reactors might be nice as well, but that would probably because excessively costly for no real improvement in safety, not to mention make compensating for a failure a bigger problem because of off-axis thrust.
Then once you arrive at Mars, drop 1 of your reactors to the planet for use in the base. If it fails, you've still got a spare in orbit (But you'll probably want to bring that back with you to Earth as well. Plan for a failure). On the way back your ship will be a lot lighter and you can use atmospheric skipping to shed some of your excess speed on the way back to Earth.
Oh, and remember all that nasty hydrogen we produced while making our breathing oxygen? Well guess what, a nuclear reactor has no problem whatsoever using hydrogen as a reaction mass. Burning your reaction mass is for chumps, real men use nuclear reactors to heat their reaction mass!
"As opposed to red sand, they actually be rocky - and, like Svalbard, they may have rock caves formed by snow and ice in the past, suitable for human habitation."
Nice to see us (humans) having to go back to caves again... I wonder if that was what the Martian's we're saying about Earth before they came here 50,000,000 years ago?
Evolution ping-pong I say!
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