Hot atmosphere? LOLWUT?

[Signo]

Yes, I brought my mammoth for the ascent the first time I was there and I discovered its "heatshield" skill. I did not try Jool in 1.0.4, so I do not have any feedback for that. The other planets obviously do not need an aerocapture (apart from Kerbin ).

My choice to go bottom first depends on the fact that I failed all my "nosediving" attempts there due to overheating. I found it easier, that's why I am advertising it.

If you correct your insertion as soon as you enter Eve's SOI it will be costly but, same as my nosediving attempts, I found it beneficial for my missions. Moreover poles are a pretty flat place where to land. North pole is rich in ore too.

I think that the problem is not overheating itself, but the turbulent convection speed barrier. Or, at least, this is the issue I had to face the most. So airbrakes are extremely useful in reducing your speed.

If you keep them outside the supposed aero flux they will not overheat but they will slow you down anyway (gaming the system...)

I use them for aerocapturing too: as I wrote above I usually go for a 70000m (or 75000, depending on the shape of the craft, the sleeker the craft the deeper I can usually go) aerocapture, starting with a more or less 4000m/s speed. I try then to adjust for an almost circular orbit. To land I go for a slow approach lowering my orbit to a 95x80.

In this case, orbital speed should be around 3200m/s that I try to correct to 2800m/s before 90000m.

I agree with you, losing the speed is the most important thing to do: as you noticed I use to bring there huge stuff like mammoths, losing that speed is the costly part of my set up. And my hard times are related to the 15000-35000 altitude range, where I usually encounter the "too low too fast" brick wall.

About the last point, I hope I succeeded in explaining how do I conduct my standard mission there. Approaching 90000m faster than 2800m/s usually does not give my ship enough edge to avoid being suddenly fried.

Just for a closure: I tried once to reduce my horizontal speed to 0 while still outside the atmo and then I did the "Baumgartner": my ship got fried at 45000.

Edited July 11, 2015 by Signo

[Geschosskopf]

Well this is simply wrong.

Um, no, it's not. All planets except Kerbin have levitating oceans, not atmospheres. The densities are WAY too much WAY too high, and the distinction between atmosphere and vacuum is practically a sheer cliff.

So there are 2 ways to fix this. Either redo the curves for the other planets so they have thin buffer zones proportional to what Kerbin has, or raise the arbitrary heights of their atmospheres to flatten out the existing curves.

[ansaman]

IIRC when I landed a probe at Eve i was going 4km/s + and hit the atmo at 85k and my probe went poof. Try slowing down to around 3km/s or less and come in really shallow. I managed to land my probe without a heatshield

- - - Updated - - -

Edit: I should note that I had to burn the rest of my fuel to slow down sufficiently. This was sure a learning experience.

http://i.imgur.com/UBkTAWp.jpg

Yeah, I had the same experience even with a heat shield with a 4K plus speed. I suspect that it is like diving into a pool from 10 feet...and then 100 feet. Same water, big difference.

[merendel]

Yes, I brought my mammoth for the ascent the first time I was there and I discovered its "heatshield" skill. I did not try Jool in 1.0.4, so I do not have any feedback for that. The other planets obviously do not need an aerocapture (apart from Kerbin ).

Honestly pretty much any engine does a decent job moonlighting as a heat shield. I've got quite a few craft that fry important bits off if they go in nose first but are just fine if I can keep em stable falling in backwards. The mammoth is just aptly named and you can hide alota craft in its shadow but I've had just as much success at rideing a tarrier down with a 1.25m craft

[Laie]

Um, no, it's not. All planets except Kerbin have levitating oceans, not atmospheres. The densities are WAY too much WAY too high, and the distinction between atmosphere and vacuum is practically a sheer cliff.

While that is right, I'm afraid it doesn't even touch on the core of the problem: reentry heat has no direct relationship to mechanical work during braking.

After some more messing around, I'm under the impression that this threat title is well chosen: reentry heat comes from convection, the surrounding atmosphere is *HOT*. It's exact temperature depends on airspeed and altitude. The faster you go, the hotter it gets, and the lower you go, the cooler it gets. How much heat a particular part picks up is determined by it's drag at any given time.

Now, in first approximation it's quite reasonable that going fast and having a high drag should impair more heat. The problem I see is that it doesn't necessarily add up to approximate the amount of mechanical work: in the upper atmosphere of Eve or Jool, you get (insane temperature * little drag) -> a lot of heat, even though your vessel barely slows down. It may well be that lowering the ceiling on Eve helps to make it more survivable, that at higher altitudes you'd get even more insane temperatures that would instantly kill you even at miniscule drag.

For me this means that it's easier to enter Eve's atmosphere with a fully fueled vessel. Even though it will eventually require a lot more braking, the increased thermal mass makes it easier for me to reach those parts of the atmosphere where real braking occurs. In contrast, the empty vessel overheats the moment it crosses the boundary.