
The ExoMars Spacecraft Approaches the Red Planet - dnetesn
http://www.nytimes.com/interactive/2016/10/16/science/space/mars-exomars-spacecraft-arrives.html?rref=collection%2Fsectioncollection%2Fscience&action=click&contentCollection=science&region=rank&module=package&version=highlights&contentPlacement=1&pgtype=sectionfront
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kordless
> The lander will attempt to touch down on Meridiani Planum, near the site
> where NASA’s Opportunity rover landed in 2004. It will study the local
> environment for several days before running out of battery power.

How sad.

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bpodgursky
Well, the Europeans refuse to consider using RTGs (scary radiation!), which
pretty much cripples any attempts to make a non-trivial rover.

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djaychela
From what I've read, that's not true - esa doesn't have a suitable supply of
plutonium 238, and is developing equipment using an alternative radioactive
source (americium).

[https://www.quora.com/How-does-ESA-plan-to-power-its-
future-...](https://www.quora.com/How-does-ESA-plan-to-power-its-future-space-
missions-if-they-dont-want-to-use-RTGs)

[http://www.space.com/692-esa-chief-europe-space-nuclear-
powe...](http://www.space.com/692-esa-chief-europe-space-nuclear-power-
options.html)

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yummybear
As far as I know even the US only has a very limited supply.

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ridgeguy
True, and production has been restarted. [1]

[1] [http://www.space.com/32890-nuclear-fuel-spacecraft-
productio...](http://www.space.com/32890-nuclear-fuel-spacecraft-production-
plutonium-238.html)

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lutusp
There's an especially interesting picture in the article:

[https://static01.nyt.com/newsgraphics/2016/10/16/exomars-
lan...](https://static01.nyt.com/newsgraphics/2016/10/16/exomars-
landing/5b10909857e42b1a309ae39f2ddc8c3f989676d8/PIA08813-victoria.jpg)

Obviously anything about Mars is interesting, but this picture has a peculiar
property. Look at the picture and imagine that the light is coming from the
upper right -- when you do that, the crater becomes a dome. If instead you
imagine that the light is coming from the lower left, it becomes a crater
again.

I've seen this in other ambiguous terrain photographs, but this picture easily
supports the ambiguity.

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stable-point
I can't get it to look like a crater, no matter where I pretend the light's
coming from. It's always a dome for me.

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DiThi
Try flipping the image. Or turning off the light: if you have actual light
coming from above you can't imagine it is coming from below.

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ramgorur
there is brittle base underneath the lander, when it drops that base breaks
into pieces to absorb the shock, interesting.

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based2
[http://www.esa.int/Our_Activities/Space_Science/ExoMars/Live...](http://www.esa.int/Our_Activities/Space_Science/ExoMars/Live_updates_ExoMars_arrival_and_landing)

[http://esamultimedia.esa.int/multimedia/publications/BR-327/](http://esamultimedia.esa.int/multimedia/publications/BR-327/)

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mblumberg
Am I missing something here? My calculator has solar panels! Why doesn't this
thing have them too?

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ramgorur
solar panels in mars did not turn out to be very efficient. After couple of
days, all those panels get covered with dust, and you need a wiper to clean
that up, which will again drain a lots of battery power.

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fbender
False. Most probes on Mars are powered by solar. E.g. Opportunity is still
going strong
([https://en.wikipedia.org/wiki/Opportunity_(rover)](https://en.wikipedia.org/wiki/Opportunity_\(rover\))).
Other upcoming landers are also solar powered.

Mission design dictates whether solar power is enough to satisfy your
requirements. For Curiosity, they wanted to go faster and longer with more
power than solar would have given them considering the size of the rover (i.e.
not much space to put solar panels on, which yields in lower power available).

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cek
Why is the Trace Gas Orbiter black?

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fbender
Probably thermal design contraints. A lot of black means high thermal
radiation (both incoming and outgoing). The orbiter is intended to fly through
the atmosphere, so to venture a guess, they want to radiate heat away quickly.

