Add an atmosphere to Moho

[Snowstorm]

*EDIT* I now disagree with myself.  The patiently persistent KSP community has explained to me why this would be an annoying pain in the rump.  Also, I screwed up the math.  (I blame Wikipedia)

 

Alright, alright, before you say, "Moho doesn't need an atmosphere!", THIS WILL NOT BE GAME CHANGING.  According to Wikipedia, the real life mercury has an atmosphere comprising of Hydrogen, Helium, Oxygen, Sodium, Calcium, Potassium, and water vapor.  Now, don't think that you can fly planes there.  This atmosphere would be incredibly wispy.  The surface atmospheric pressure on Mercury is about 10^-14 bar, or about 1 pascal.  If the Mars-Duna atmospheres are equal, this would mean that Mercury's atmosphere would be 600 times as this as Duna's.  I suppose it could support tiny, tiny, amounts of aerobraking, if any, but otherwise be nothing big.  Just something I noticed.  Feel free to debate this.

 

Edited May 20, 2016 by Snowstorm

[Panel]

I really isn't necessary. That thin of an atmosphere would be so incredibly neligible, that it would be easier not having it. 

[Gaarst]

The Moon has an atmosphere, so does Pluto. The reason why extremely thin atmospheres are not added to the game is because KSP can't handle number as small as 10^-14 bar.

Also it would literally change nothing so there's no point in adding one. And KSP is not a replica of our solar system, if Mercury has an atmo doesn't mean Moho should have one.

Edited May 18, 2016 by Gaarst

[Snowstorm]

Ok.  I understand all this.  If the game can't handle it, and it's not necessary, I'll back down.  I don't have strong feelings for this.  Just a thought I had.

[Wjolcz]

NovaSilisko, who made the planets, said that Duna was the smallest body with an atmosphere that would look good. Basically the atmosphere on Moho would look really weird because of it's size and that's why we don't have an atmosphere on Eeloo (which originally was meant to be there).

Unless Unity 5 brought some cool graphic/tmospheric effects there's no way to make it look good afaik.

[Snark]

18 hours ago, Gaarst said:

Also it would literally change nothing so there's no point in adding one. And KSP is not a replica of our solar system, if Mercury has an atmo doesn't mean Moho should have one.

Actually, it would change something.  It would make the game more annoying and less convenient without adding any actual challenge or gameplay.  It would mean that the ship would shift into "atmospheric" mode as soon as you get close to the planet, meaning you can't do timewarp, have to do physics warp, can't go over 4x, etc.  A pain in the posterior, for no gain whatsoever.

Also, if you decided "we have to model atmospheres down to 10^-14 bar" ... that means for consistency you'd need to raise the heights of the top of all the "atmospheric" planets by many, many kilometers.  Do you really want to be plowing through Kerbin's atmosphere and unable to timewarp when you're 200 km altitude?

 

[Gaarst]

1 minute ago, Snark said:

Actually, it would change something.  It would make the game more annoying and less convenient without adding any actual challenge or gameplay.  It would mean that the ship would shift into "atmospheric" mode as soon as you get close to the planet, meaning you can't do timewarp, have to do physics warp, can't go over 4x, etc.  A pain in the posterior, for no gain whatsoever.

Also, if you decided "we have to model atmospheres down to 10^-14 bar" ... that means for consistency you'd need to raise the heights of the top of all the "atmospheric" planets by many, many kilometers.  Do you really want to be plowing through Kerbin's atmosphere and unable to timewarp when you're 200 km altitude?

 

Oh, didn't think about that. It would indeed change things. Though I'd prefer no change to that kind of change.

Edited May 19, 2016 by Gaarst
Typo

[Snark]

Another handy thing to realize:  if you like the idea of hyper-thin atmospheres and would like to play with 'em... you can have them! 

Just install Kopernicus, and you can mod the planets to your heart's content.  A simple snippet of ModuleManager config will allow you to add a hyperthin atmosphere to Moho, or extend Kerbin's atmosphere up to 300 km, or any other permutation your heart desires.

Also:  A minor math correction to the OP.  You're off by a factor of a billion. 

A pressure of 10^-14 bar isn't 1 pascal.  It's about a billionth of a pascal.  One pascal is roughly 10^-5 bar.

Just to give you an idea of how astoundingly thin that is:  it's so close to a vacuum that you need incredibly sensitive instruments even to detect that it exists.  It's so astonishingly tiny that if you do the actual math (Moho radius 250 km, gravity 2.7 m/s², pressure 10^-9 Pa), it comes out to a total mass for the entire atmosphere of Moho of just under 300 kilograms.

That's right.  Not tons, kilograms.  As in, "take the mass of three HECS probe cores and smear it over the entire surface of a planet, filling up a volume dozens of kilometers high."  As in, "vaporize one rocket by crashing it into the planet and you'd multiply the planet's atmosphere by a factor of 10 or more."

Now that's thin.

Just to share an anecdote:  way back in the dim mists of ancient time when I was a college student, I had a summer internship job working at a government lab, where I needed to work with super-ultra-high-vacuum systems.  The absolute hardest vacuum the system was able to obtain was something like 10^-10 bar, if I recall correctly (it's been a long time, I could be off by an order of magnitude or more, but I think that was the ballpark)-- that's 10,000 times denser than the atmosphere you're proposing.  And even that much required a complex three-stage vacuum system (mechanical pump, followed by an oil-diffusion pump, followed by a supercooled-liquid-helium cryopump... it was nifty!), and many hours of operation to pump even a fairly small volume down to that level.  And it was nearing the resolution of the pressure-monitoring instrument just to tell how low it was.

So, yeah.  Really, really no point in trying to model that in-game. 

[John FX]

I am of the opinion that a difference that makes no difference is no difference.

Meaning, if you can`t see it, and it won`t affect your craft, why bother using CPU cycles to calculate it`s lack of effects?

[Snowstorm]

You are all right.  I have seen that this suggestion would be of no use, and would only cause annoyance.  However, @Snark, thank you for reminding me that I an use Kopernicus to achieve this.