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Comment by BrazzVuvuzela | Hacker News Reader

Is water on Mars even exciting? We're already quite certain there is a ton of water on Mars... in the form of ice. The exciting discoveries are evidence of liquid water.

> The bulk of the northern ice cap consists of water ice; it also has a thin seasonal veneer of dry ice, solid carbon dioxide. Each winter the ice cap grows by adding 1.5 to 2 m of dry ice.

> The part of the cap that survives the summer is called the north residual cap and is made of water ice. This water ice is believed to be as much as three kilometers thick.

https://en.wikipedia.org/wiki/Martian_polar_ice_caps

That's a lot of water!

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It is very exciting in the equatorial regions as it was typically assumed that because of the high summer temperatures (~70°F), any ice would melt and the water would evaporate. Valles Marineris would be an excellent location for a human settlement because of these warmer temperatures and the higher atmospheric pressure in the canyon. If there is water there as well then it ticks all the boxes.

> higher atmospheric pressure

But the pressure is still effectively nil. It's far below what would be needed for humans to venture outdoors, and makes a negligible difference to the strength required for pressurised buildings.

I believe it would make it easier to land supplies there though, since there is more atmosphere to aerobrake with.

Can you aerobreak all the way into the cannon though?

Every bit helps, right? Even if you're using retrorockets by the time you're that low, atmospheric drag should still be helping.

It is a few hundred kilometers wide.

Absolutely but every little bit helps. A thicker atmosphere also means less radiation, thus less radiation shielding required. I don't have numbers on hand but from what recall it is a significant enough of a difference to worthy consideration.

I am sure someone will eventually come up with the crazy idea to seal the canyon and pressurize it.

The Martian soil is still unsuitable for humans since it's full of toxins.

https://www.space.com/21554-mars-toxic-perchlorate-chemicals...

The same article makes it sound pretty manageable. Showers for the spacesuits, microbes that eat it, and useful properties.

Could human settlers on Mars adapt to progressively lower pressure levels over time (generations)?

Yes and no. Yes because there are people on Earth adapted to living at great heights (the Andes or Himalaya) and no because the pressure on Mars is far too low. At Mars' pressure, the boiling point of water is so low that our body temperature is too high and makes the blood boil.

https://en.wikipedia.org/wiki/Armstrong_limit

I wonder how much difference it would make to the pumps sucking in Martian air to create fuel and pressurized atmosphere.

If we found microscopic life forms in the water though, would we create a settlement or not? It would be so easy to contaminate stuff with a settlement there. I could see people pushing for it becoming a reservation, only to be studied from very far away using hyper-sterilized robots. At least for a while until we are sure we've exhaustively cataloged everything.

Finding life would be huge, we're not going to just go settle on top of it willy-nilly.

Hasn't stopped us on the local planet.

To an extent, it depends on what we find. What kind of biology does it have? How many species are we talking about? Can we throw it in a bio-bank somewhere and move on? Will it outcompete any Earth life we try to seed? Could it be dangerous if it colonized the Earth?

Earth should be as unsuitable for them as mars is for us, except in the case of non alive organisms like viruses or prions. But to have viruses you need higher forms of life supporting them, those based in cells

If we found some alive in Mars and we could found it quickly if we found a cannon with water, we should call them in a distinct way. I will propose marteviruses:

Marte-herpesvirus, Marte-adenovirus, Marte-coronavirus, etc.

Another way could be putting before a M- prefix but would be less convenient to read

Which is what scares me. Yes it s cool to protect the local microbes but damn arent we also an important local life form of the solar system that would leap one level in evolution by just living on two planets ?

Should we lose that for the sake of microbs, as long as we can preserve them for study?

Contamination goes two ways.

One of the interesting consequences of water on Mars is the fact that it can be used to make methane and oxygen (used by both SpaceX's Raptor and Blue Origin's BE-4 engines). This potentially increases the amount of cargo one can carry from Earth to Mars as one no longer needs to bring hydrogen (for the Sabatier process for making methane) from Earth for the return trip back to Earth

That sounds like a ridiculous waste of such a scarce resource.

Why? This is one of the only economic advantages for settling mars; serving as a lower-g refueling station.

Unless the water is replenished somehow, sending it all off-planet would mean no one could settle Mars.

How much water do you think is on Mars?

Refueling for what? The realities of orbital dynamics mean that Mars isn’t a convenient stopping place on the way to say, the outer solar system. I don’t have the numbers in my head but the delta-v requirements to intercept, match velocity and land negate any potential refueling benefit in my understanding. (Not to mention the added complexity vs a straight shot, this is a lot to pull off even in a sim like KSP)

You might be able to make an argument for refueling bases on Mar’s tiny moons with their negligible gravity wells for Martian missions themselves but that’s about all I can see.

What am I missing?

You're not missing much, but orbital transfer hooks from Mar's moons work out.

But what if you built a base there that continuously flung refueling pods into orbit? Make these pods leave orbit to rendezvous with another craft somewhere else rather than the craft needing fuel to come to a stop on Mars.

>According to the researchers, 40 percent of the near-surface material of the 15,830 square mile (41,000 square kilometer) region could be water ice.

That’s potentially billions of tons of water ice.

Every deposit of water, even as ice, opens a new series of inquiry. Suddenly you have new regions, geographies, biogeochemical hypotheses, and potential support for life. More history, more to explore.

New sites give us more to consider for future missions and broaden the set of experiments we want to conduct.

I'd much rather keep finding water, even as ice, then have the planet run dry. It only increases the odds.

For anyone born in the 20th century I’d think so.

If you’d have said there was water on mars in 1970 you’d have been met with disbelief. 1980? 1990? Later?

I think this is a failure of science education more than anything else. The polar ice caps of Mars were first observed in the 17th century.

https://en.wikipedia.org/wiki/History_of_Mars_observation#Ea...

It was observed simultaneously as canals and vegetation were "observed", and roundly discarded by 1970s. Water on Mars remained unconfirmed until this century.

Though I distinctly remember reading in an encyclopedia from the '70s that certain large dark regions on the Martian surface were believed to be thick vegetation (: I'm not kidding!

From [1]: "As recently as the early 1960s, it still seemed possible to a few astronomers that the dark regions had some kind of plant life because they seemed to darken each summer as if plants were growing in response to sunlight."

[1] https://www.jpl.nasa.gov/images/pia02362-the-dark-surfaces-o...

Yes, I remember reading books from the 60s my grandmother got from a charity shop. They had wonderful illustrations of Mars with vegetation and where the canyons discussed in the article were canals full of water. It's easy to forget just how much we've discovered about the other planets in the solar system in the last 50 years.

There is so much science fiction writing from the golden age and beyond, up to the 60s and 70s, which prominently features Martians and Martian cities. Mars having alien life was a massive source of speculation among the public at that time. While the stories are still great, reading them today I can't help but go "nah we've been to Mars, there's nothing there".

Makes me think about how soon sci-fi written today will get similarly outdated.

I remember a sci-fi novel from the 60s or 70s, where a forgotten punch card was the only artifact left over from aliens long gone.

I think that something similar awaits modern science fiction in 50 years.

I'm reading Red Mars at the moment, written in the 1990s and set in the 2030s, and a cluttered lab is described as having piles of floppy disks lying around. So, yeah.

Makes one wonder what science of today will be looked upon with quaint humor in 50 years' time.

Astronomy Picture of the Day on April 1st 2005: NASA finds water on mars[0].

[0] https://apod.nasa.gov/apod/ap050401.html

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