I wrote this a few days ago in an attempt to crystallize my understanding of the Mars missions from many perspectives. I think they're largely a boondoggle - but one which we are unable to prevent, and so we must be happy with the story they tell and the secondary benefits they entail. It's in our nature to want success for this sort of thing.
I know the writing might be improved, but I think I have the gist of it here. Read if you have a few minutes.
Thx,
Blabberman
Reason to go to Mars: To find Extraterrestrial Life. The Holy Grail of all science.
(1) Robots - already well under way - at great, but not insurmountable expense. No Return Trip.
(2) Humans - a distant pipe dream - theoretically possible at almost-infinite expense. This would include a return trip with evidence, artifacts, etc.
Question: Why?
Answer:
1) Because it would be significant in redefining our place in the universe where life was everywhere, where we are not alone.
2) An alternate, Martian version of life would tell us about how evolution works in seperate environments, what features of genetics are essential and through convergence had appeared on both planets and what is unique to either Earth or Mars. Biology would be vastly richer for having multiple versions for comparison
3) (a) It is like Mount Everest, something that Man has never done before. Such a feat offers a chance for high-achievers and politicians to write something in the history books which would last for millennia - the crowning achievement and pinnacle of our technological civilization - perhaps never to be surpassed.
3) (b) It will enjoy wider support because it plays in to the vision of who we aspire to be - both individually and collectively. Americans are a powerful people of strong will who are able to cooperate to achieve amazing things.
4) It's a jobs program. Just as the defense budget is bloated as a result of congressmen working to support their state local economies and corporate patrons, an expanded Mars program lends another High-minded cause and a fig-leaf of credibility for plans to siphon money out of the federal government into local purses.
5) And it's a basic research funding program. The science of past space exploration programs led to spin offs in computer miniaturization, satellite communication, radar and dozens of other secondary technologies.
The Apollo program in the 60's developed dual-use technology and directly supported Cold War ICBM design. It complimented the defense budget and was a centerpiece to show our superiority over the Soviet Union.
That is no longer the case. Though we still have military adversaries, all the problems & questions of how to deliver warheads around the globe quickly and accurately have been solved decades ago. A Mars mission won't add to our abilities.
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One thing that will never come to pass is Mars as a terraformed living space for humanity. Because of the cost of getting down to the Martian surface & getting back to space, this will never ever be economical. And without a profit, this will always be a discretionary science expenditure for governments and scientists .. and that's it.
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HOWEVER:
We know already the nature of the life that might be on Mars. It would most likely be only in fossil form. If it has survived until today it would be microscopic. There is no liquid water on the Martian surface and there never has been for any length of time. The sun has continually become hotter since it's inception 4.5 billion years ago, such that the earth was at one time completely frozen over - i.e. 'snowball earth'. So Mars, which is now outside the Goldilocks zone where liquid water can exist - was back then even farther out of the zone. Perhaps someday in a billion years there will be enough energy from the expanding sun for liquid Martian water, but not yet.
The other source of energy to melt surface-water would be volcanic activity, and indeed evidence shows that at one time there were oceans on the Martian surface - perhaps only during major eruptions or meteor impacts - it's hard to tell.
But that was long ago. The red planet once had a molten core like the earth, but this core seems to have solidified some hundreds of millions of years ago. As a result it has no electric-magnetic field which would protect an atmosphere from the effects of the solar winds which constantly deplete it, including any gaseous water molecules - lost to space. And without an atmosphere the sun's rays include sterilizing ultraviolet light.
Without a molten core Mars also lacks Earth's plate tectonic activity and so all of its volcanoes have gone extinct. Even on the very rare days near the equator where the temperature is high enough for liquid water the atmospheric pressure is so low that any ice sublimates to gas and is lost, and any water evaporates quickly as well.
The upshot:
There are currently very few if any places where life could now exist on Mars.
Perhaps there are pockets of heat near deposits of uranium which could support life - a tiny vestige of what might have existed many millions of years ago. But that's it. It wouldn't be much.
Perhaps we can add nutrients to some ancient rocks with the remains of ancient bacteria, which might then spring to life - as often occurs in earth rocks from deep underground. The DNA goes on in an inanimate state, but still able to reconstitute itself.
It would probably appear similar to lichen. It isn't producing detectable oxygen in the atmosphere so it wouldn't be using photosynthesis. That leaves .. anaerobic processes that take energy from sulfur compounds, or some similar exotic process.
So are we 'Not Alone' because - after years of dedicating vast resources in the quest - we have found this lichen-like life form on rocks in a Martian cave - a remnant - or a small island of life in the red, frozen desert?
No. I would submit that we are the same. I doubt (though I have no proof) that life on earth is vastly more complex and sophisticated than whatever is on Mars - simply because there's more of it & more evolution has thus occurred here. So we have nothing to learn from Mars. We would have some solid knowledge and would be able to make the evolutionary comparison, and something which is currently only speculation would be made real.
That life - once it is found - cannot be vastly different than earths' form of life. We have solid chemical reasons why life is based on carbon molecules and water. No other combinations of elements have similar properties. It can't be silicon or arsenic or something else - there is No-Other-Way. It is of course unknowable, but everything we understand about biology would lead us to believe that Martian life would largely overlap with earth-based life. The discovery would be mesmerizing, but it would not change our understanding of any of the most basic fundamentals of biology.
We could bask in the achievement and feel great about it - but that's it. We can't have a conversation with the Lichen about the nature of God or mathematics or whatever. It will be quite silent. Something that is almost certainly true will be proven. Then .. the Martian life would most likely be an involuntary food-source when it comes into contact with earth-bacteria.. And the story of Mars Exploration ends - we will have explored the nearest frozen desert in the solar system. End of story.
One could say that it's like the Olympics - a huge spectacle full of pomp and circumstance which invariably loses money and leaves a wake of abandoned stadiums .. supported by self-interested businessmen with stories that are their own reward .. and yet we are compelled to watch and support the whole thing.
We are so tied into the narrative - it fills such a deep and primal place for us that we cannot resist. The Olympic movement feels the human psyche better than a watch movement and has found itself an indispensable niche to fill. - as will the Martian Missioners. We need elite achievement. We need a risky quest to an unknown place, and we need to conquer the unknown, just as with Asia or Africa in the 19th century, Mars is the final destination. They don't have to sell. We're buyers by nature and they're the only game in town.
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And Yet
I strongly doubt that any human will ever set foot on Mars. Not within my lifetime.
Not within the millennia. Probably Not Ever.
The reason: With the 1% atmosphere, there is no way to deliver any large payload to the Martian surface. Nothing over 3-4 tons. Beyond that weight no parachute would be large enough or work fast enough to slow the spaceship's descent. The alternative would be using rockets to slow it down, but that would mean a very large % of the mass of the whole mission would be just this descent mechanism. It could easily amount to over half the total.
We could not deliver anything bigger than a minibus to the Martian surface. And we'd need to get something somewhat larger than that - that is, a rocket to get back into orbit for the return trip to earth. Something as large as the Space Shuttle would be unnecessary in Martian gravity, but the rocket would have to be very substantial. I would guess .. 20 tons (?). These factors make this mission almost impossible.
Other significant technological obstacles include the difficulty of shielding the interplanetary spacecraft from the solar winds which would cause radiation sickness, and the effect of prolonged weightlessness for the 2+ year journey - several months would en route.
The chances of everything going perfectly would be - I would guesstimate .. 20%. That might have been acceptable for the heroic 19th century. It is far too low for current technology. Even though I am sure qualified volunteers would step forward, no technology program today would accept those odds. We're no longer strong enough for it.
And so it will remain a fantasy - always there, well within our imagination and our robots, but beyond our reach. Like a new Stone of Sisyphus that we can contemplate but will always step back from pursuing.