How to Give Mars an Atmosphere, Maybe (2017) | Hacker News Reader

How to Give Mars an Atmosphere, Maybe (2017)

nautil.us

25 pointsdnetesn56 comments

There is not enough CO2 or any other such gas on Mars to make an atmosphere better than 5% of Earth's, even if you razed the surface kilometers down and boiled the ice caps and installed an artificial magnetosphere.

https://doi.org/10.1038/s41550-018-0529-6

20 millibars is essentially the long-term limit without piping in gas from other planets or comets.

There's plenty of science and exploration to be done on Mars, and efforts towards getting people there are admirable, but let's keep it red. Non-scientists (like Elon) should at least consider not ignoring the data we've spent billions of dollars collecting and confirming over the past 50 years.

I just don't get the point of humans living on Mars. Literally the entire surface of the earth, including the seafloor, is more habitable than Mars and can be reached without having to fight the rocket equation. Sure, thinking about space travel and terraforming is fun, but what compelling reason is there for mankind to invest unbelievable amounts of resources in actually doing it?

off-site backup?

Seriously though, another independent human colony would lend some much needed perspective to the worlds political problems.

Also what if just because we can might be enough reason? Maybe we can't, that would be quite important to know too.

These are the standard arguments people bring in favor of human spaceflight. I don't find them compelling enough to justify the enormous cost of such a project. A serious attempt at colonizing Mars would probably consume a significant fraction of the GDP of whichever country/ies is/are doing it. Currently, we are not even close to investing such amounts of money in order to solve much more pressing issues, such as climate change.

All of NASA is less than 1% of the US federal budget, much less GDP. I think you're overestimating the price.

The total cost of even current environmental regulations, much less the proposed solutions to climate change, are orders of magnitude larger.

This year, a total of four NASA astronauts have been launched into LEO on russian rockets. This is not at all comparable to colonizing or even terraforming a planet.

..while multiple Mars and other planetary missions are ongoing and a new launch vehicle to bring humans into space is being developed. All on that 1% budget.

None of that is money problem though. Your (I presume) country has like 11 aircraft carriers? + 2 being built and 2 ordered (https://en.wikipedia.org/wiki/List_of_aircraft_carriers_of_t...)

What can 11 do that you can't with 8? & the matching carrier group.

Having somewhere else that none of that applies to would be incredible.

There's a more or less linear relationship between the number of carriers and how much time you have them deployed. They require an awful lot of maintenance.

Which I'm not weighing in on whether more are necessary, just that more carriers does mean more time deployed.

Imagine the perspective when 200 people run out of food and people start proposing spending billions of dollars to bail them out.

Those billions of dollars need to be an upfront investment to make the colony self sustainable with backups.

Because that's what we do. It is kind of our thing as a species to inhabitate new areas.

Also: When all our immediate needs can be covered, what, except from medicine, is there to explore? The solar system is a way too interesting playground to ignore it.

Mankind has inhabited new areas when it made sense to do so. In fact, most of earth's land surface is _not_ inhabited, and large parts, such as the poles, have never been.

We are not even close to covering everyones immediate needs in a sustainable way. 85% of the global energy production relies on fossil fuel.

Totally agree with you. This irritate me so much, reading about terraforming and living on mars. It’s such a grotesque nonsense talking about terraforming another planet while we are destroying our perfect and beautiful earth.

This terraforming Mars argument always sounds a bit “mechanical horse” to me. By the time we’d be able to do this, we would have merged our “survival machine” human body with technology and would not require the incubator of earth’s environment to survive. Feels more likely that in a century or two we’d have essentially immortal carbon nanotube exoskeletons wrapped around human brains going wherever the hell they want across the solar system and beyond.

Would have appreciated if someone noticed the spell-checker underlining in the slide screenshot and...fixed it.

If terraforming Mars were to be successful, wouldn’t the long-term livability of Mars still be hampered by having about a third of Earth’s gravity?

I imagine it to dramatically affect human physiology, making it perhaps impossible for Martians to ever return to Earth.

Could people who plan to return to earth live in large centrifuges?

It's not known whether Mars gravity would be sufficient to maintain "Earth compatibility".

The whole point of the centrifuges is to increase the force experienced by the people, up to the point where it is comparable to Earth's gravity.

Yes, but we don't have empiric data on people living in a third of Earth gravity, only 0G from space stations. A third may be enough and no centrifuges necessary.

“My understanding of terraforming is the deliberate addition, by humans, of directly adding gases to the atmosphere on a planetary scale,”

Not only adding but also removal of the 700ppm carbon monoxide.

700ppm (at 1% Earth sea level pressure), is maybe too little be a problem?

There is no gas other than carbon dioxide on the entire planet present in large enough quantities to be useful. At equilibrium with a >90% CO2 atmosphere, it's impossible to remove all of the CO.

Also, the lack of a magnetic field to protect from solar radiation.

I think this is the crucial point. When I heard this I gave up hope.

Why? You’re not going to be spending most of your time out on suits anyway. Put some sandbags on the roof.

Because the atmosphere will be stripped away by the Sun. But see comment about generating a magnetic field.

Yes, over billions of years the atmosphere will be stripped away. But the process is way too slow for us to worry about.

https://phys.org/news/2017-03-nasa-magnetic-shield-mars-atmo...

NASA estimates, given Mars was given a magnetic field, it would only take a century (give or take) to start to melt oceans. So your estimate seems to be off by a bit.

Did you reply to the wrong comment?

No - it means that the solar wind is affecting the atmosphere enough that a greenhouse effect on Mars is not getting started, even though it could if there was a magnetic field on the planet.

This means the solar wind effect is not negligible. An artificial magnetic field plus other means could have a drastic and extremely rapid (in geologic terms, hundreds of years) effect on Mars climate.

This article discusses how a magnetic field can be generated to protect Mars and it's atmosphere from solar winds.

There might be mitigation strategies.

First step: colonize Valles Marineris. (It's as much as 7km below mean surface level, so the atmosphere is going to be considerably thicker at the bottom than at surface level: for reference, that's the same height as Mount Everest, although due to the difference in gravity the scale height is higher, meaning you don't get as good a pressurization increase as you would on Earth).

Second step: build residencies by drilling horizontal tunnels into the cliff walls and pressurizing the entrances.

Third step: throw large mylar domes (or even roof) over the floor of the canyon and actively compress the air down there to get it up to a temperature at which crops will grow. Scavenge oxygen produced by photosynthesis from the mostly-CO2 atmosphere using cold traps.

(Your colonists aren't exposed to the solar and cosmic radiation because they're living under a couple of km of rock, and their crops are under almost double ambient atmospheric pressure even before you add active pressurization to the farms.)

Note that Vales Marineris is 4000km long and up to 200km wide in places. It's huge -- ISTR hearing that it has roughly the same land area as Germany (but can't find the source right now).

Your comment made me even less hopeful we can colonize Mars.

What are the benefits that would drive such colonization? On Earth there were rich resources driving human expansion into new areas. This Mars expansion would be like humans repeatedly trying to live in the Atacama desert but orders of magnitude even more harsh. Mars is constantly trying to kill you, and is fantastically expensive due to the distance to Mars and cost to transport things there. What reason would we have to make us attempt it?

> Mars is constantly trying to kill you,

And the Earth could be trying to do the same in 100 years.

You believe earth and mars will be on par in terms of habitability in 100 years? If I were confident I would live that long I would take that bet.

Unless you're thinking of some cosmic catastrophe- and a much worse one than the asteroid that killed the dinosaurs-, there is no comparison whatsoever between any disaster that can happen on Earth and the environmental conditions on Mars.

Honestly? Some megacorp that discovered a profitable reason to be up there could (and probably would) make the whole thing happen. They would have the motivation, and the colonists would be glad for the excuse to get up there.

Radiation on Mars is at a level similar to the background radiation in Ramsar, Iran. People there have normal life expectancy and cancer rates.

https://caseyhandmer.wordpress.com/2019/10/20/omg-space-is-f...

Long-term livability is a separate issue to the ability to return. The whole point of colonization is to be able to stay... forever.

Artificial gravity can be added by rotating cities. Not cheap, nor easy, but possible.

JAXA did a 1/6 g (like the Moon) experiment with rats in a centrifuge on the ISS this summer and when that gets published we'll have our first data point on how low gravity effects mammal physiology. But really, we currently have no idea if Mars gravity is just as good as Earth gravity or just as bad as freefall.

Isn't the problem with a artificial atmosphere also the low gravity? How to solve that? Or is it strong enough that the loss can be compensated?

Why is this marked as (2017) when it's dated November 15, 2019?

Let’s fix our own planet first before fixing another one ha

This is a silly argument. We can do more than one thing at a time.

We are certainly very good at rearranging multiple deck chairs on the Titanic at once. Our ability to grapple with any serious problem affecting the entire human system appears to be low at present.

Not so silly. Resources are limited

Are you in charge of all the resources? If not, it's a silly argument. People will do whatever they want to do. You might as well propose herding cats.

Maybe is silly for you.

"If you are not (put some impossible random requisite here) then you are wrong"

Well... As other billions of people, I don't need to be "in charge of all the resources in the planet" or "to be Santa Claus or Jesus" to talk about the problems of humankind (or to be aware that neglecting earth conservation, to put five machines more or less in Mars none less, is a terribly stupid idea). If you equal asking more resources for nature conservation with proposing herding cats, then your logic has some serious loopholes.

Those loopholes are features, not bugs. They allow the mind to close the door to consideration of reflexive problems. Those with a feedback loop back to the self. It really simplifies existence! xD

I think your buffer has overflowed. If living sustainably within limited resources were merely a "thing" to take care of one afternoon, or even in 1000 afternoons, then we probably would have done it by now.

Consider that the need for this "new thing" (Martian living) may have only arisen from the failure to solve the first thing.

Well we haven’t even taken a human to Mars, do you realise how much resources it will take to just achieve that, and for what purpose? It’s a vanity project.

It's a long term survivability project. Living on one planet is inherently dangerous. And long-term - terminal. You're one step away from some relativistic rock hitting out planet and sterilizing it.

Let's learn how to fix a planet with one we don't really care if we mess up.

Yes, one we’ve never even visited! Makes sense

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