
Mars Express gets festive: A winter wonderland on Mars - kartikkumar
http://www.esa.int/Our_Activities/Space_Science/Mars_Express/Mars_Express_gets_festive_A_winter_wonderland_on_Mars
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curtis
Geoffrey Landis made a proposal for a polar landing site for the first manned
mission to Mars back in the 90s. One of the clear advantages is that you don't
need to bring hydrogen with you for the return trip, but instead you can just
make it from the ice. Landis proposed the mission for northern hemisphere
summer so that solar power would be constantly (or nearly constantly)
available. One thing Landis didn't mention but is worth considering is that
ice could be used for radiation shielding, either by tunneling into it or by
melting it and reforming it into a surface structure.

However, landing on the polar ice cap has some downsides, not least of which
is it would be the most boring place on the whole planet to land.

Korolev crater might make a good alternative site since you could conceivably
land near a substantial amount of easily accessible water ice while still
retaining easy access to terrain that is not ice-covered.

[1]
[http://www.geoffreylandis.com/pole.html](http://www.geoffreylandis.com/pole.html)

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maxxxxx
" you can just make it from the ice"

I always read this but do we really have the tech to this without needing big
and heavy equipment and a lot of energy? Why don't we "just" do this on the
South Pole?

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Tuna-Fish
> I always read this but do we really have the tech to this without needing
> big and heavy equipment

Sure, the chemistry is simple and well understood and the equipment needed
isn't that heavy.

> and (without) a lot of energy

Nope. Splitting water is heavily endothermic. The SpaceX BFR Mars mission plan
would require ~3MW continous for two years for the energy required for CO2
capture and chemistry to make enough CH4+O2 to return to earth. This is a
massive amount of energy, basically requiring either a quite respectable
fission reactor or ~10ish MW of solar panels, which take about a single BFS
cargo hold by themselves.

The reason these kinds of plans are floated regardless of the energy costs are
simply that carrying that much power production down there is still much
easier than taking enough fuel with you to return home.

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ddingus
>that carrying that much power production down there is still much easier than
taking enough fuel with you to return home.

Rationally, yes. This sentence makes sense. But, I find it amazing and
difficult to visualize just how EXPENSIVE FUEL is.

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pseudolus
That's quite probably the most impressive picture of 2018. For a long time
there was a belief that earth was singular in possessing an abundance of water
and now spectroscopy has revealed the presence of water on other planets and
fly-bys by probes show geysers erupting from the surfaces of moons. Science
advances even if it's not always at the pace we would like.

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danbruc
Hydrogen and oxygen are the most (~75%) and third most (~1%) abundanten
elements in the universe and this has been known for quite some time, so it
does not seem that unexpected that water is not especially rare. But maybe the
formation of water from gases requires conditions that are at least somewhat
rare in the universe.

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pseudolus
True enough, but if you are old enough to remember the 1960's and early 1970's
the belief, at that time, in the presence of water on other bodies in our
solar system was never a given.

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donpdonp
I'm a bit confused - werent the NASA landers looking at the Martian dirt for
microscopic traces of evidence of water in the past? or perhaps digging for
some sign of water? and the NSA probe just flys by and says hey look out the
window, there's a entire lake of frozen water, sitting on the surface, that
noone has ever observed before.

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jessriedel
This image is digitally generated from topographical maps collected by
satellite. There are no probes on Mars that are located in a place where they
could actually take a picture like this. EDIT: My first sentence was wrong. As
finnh points out, it's actually based on a real satellite photo that was then
stretched to give the illusion of a perspective from low altitude.

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phkahler
And yet the article says: this feature, known as Korolev crater, is found on
Mars, and is shown here in beautiful detail as seen by Mars Express.

It is in fact a synthetic image constructed from a couple data sources. Not a
real image taken from a camera. It may as well be one of those "artists
conception of...." images used whenever a new planet is discovered.

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finnh
I think that's just for the perspective, though? We'd have to be flying much,
much lower to get the perspective shown in the image.

The straight-overhead view is less CGI-y (still composed, but of multiple
overhead strips):

[https://www.esa.int/spaceinimages/Images/2018/12/Plan_view_o...](https://www.esa.int/spaceinimages/Images/2018/12/Plan_view_of_Korolev_crater)

I'd like to know more about the input images...

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jessriedel
Thanks for this info.

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beart
For anyone skipping the article - This is actually a composite image and not a
single photo.

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jessriedel
Its not a composite photo either. It's a fully artificial visualization based
on real topographical and composition data. EDIT: nope, I was wrong, it's
actually based on a real satellite photo that was then stretched to give the
illusion of a perspective from low altitude:
[https://www.esa.int/spaceinimages/Images/2018/12/Plan_view_o...](https://www.esa.int/spaceinimages/Images/2018/12/Plan_view_of_Korolev_crater)

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jonknee
> artificial visualization based on real topographical and composition data

Yes, that's what they mean by a composite.

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jessriedel
"Composite photo" means "multiple photos combined together" not "artificial
picture generated from information on chemical composition".

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jonknee
They used topographic data and visual imaging to create the "composite" image,
that's accurately described as a composite in my book. Similar to zooming
around a city in Google Earth.

Here's the top down view (still quite spectacular!):

[http://www.esa.int/spaceinimages/Images/2018/12/Plan_view_of...](http://www.esa.int/spaceinimages/Images/2018/12/Plan_view_of_Korolev_crater)

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sidcool
Images like this one give me goosebumps. It's another planet!

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starbeast
I got the shivers from this as well. It is not only absolutely fucking
stunning in and of itself but considering what it took to be able to see this
image, all of the people responsible are utterly magnificent bastards. Also I
have had a thoroughly shit week, so I wish them extra thanks for gifting me a
bit of optimism, which I sorely needed. Awe is an overused term, but here it
genuinely applies.

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seiferteric
TFA mentions that the air above it gets cold and sinks creating a cold air
layer, presumably it is more dense. Any idea how dense this air would be?

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jstanley
I don't think it would be particularly dense, it's just denser than the other
air on Mars. Mars's gravity is less than Earth's, so the air will probably be
less dense than the air over the arctic.

EDIT: According to
[https://en.wikipedia.org/wiki/Mars](https://en.wikipedia.org/wiki/Mars) ,
typical atmospheric pressure on the surface is about 0.6 kPa, compared to
about 100 kPa on Earth. That's a bigger difference than would be explained by
gravitational differences alone, so probably the fact that there is just much
less atmosphere is more important. Either way, it's substantially less dense
than any air you're likely to encounter on Earth.

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remcob
Gravity on Venus is 0.9 that of Earth, but it's atmosphere on the surface is
90 times as dense. Surface gravity doesn't say much about atmospheric density
(the mass of the atmosphere does).

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ddingus
This is simple, but how many of you want to go there?

Pictures like this make me want it. To stand somewhere on the ice, maybe brush
a little snow around and see the rim all around... it's like a little island,
delicate.

We are living in fantastic times!

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imglorp
Well, now we know where to land the first fleet of robotic air and fuel
factories.

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AtHeartEngineer
Snowboarding on Mars anyone?

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sempron64
It's an interesting question whether this would work. A lot of the low-
friction properties of snow are due to pressure-based melt. I wonder if skis
or a snowboard would slide well in this crater, both due to the low gravity
and extremely low temperature. Maybe with size adjustments to optimize surface
area and pressure for an adult human weight it might work, but I have no idea
where to even start this calculation.

