How dangerous is duna’s atmosphere

[RocketSquid]

I was wondering how much thermal protection a duna mission needs. Does an aerobraking need a heat shield? Does a standard reentry profile (with a lander, not a space plane) need a heat shield?

[TheTripleAce3]

Keep pe above 20 km and you should be fine.

[bewing]

Do you mean an aerobraking pass from interplanetary velocities? Or are we talking about strictly orbital velocities? Standard reentry is very slow and needs no heatshield at all.

Edited May 17, 2019 by bewing

[cantab]

It's not. I've re-entered all sorts and I don't think I've ever had anything blow up. Unless you come in with really excessive speed you'll be fine as far as heating goes.

On the other hand if you're not careful you can end up hitting the ground too fast for your chutes or landing engines to stop you, so watch out for that.

[JadeOfMaar]

Duna's atmo is not dangerous with regard to heat. It's dangerous with regard to how scarce it is. It's often described as "just enough to liquid you off" as there's not enough of it for you to fly or land an aircraft well, aerobrake very well, or rely entirely on chutes for landing, so you might as well treat Duna as airless...but Duna still has an atmo so you can't treat it as airless and you need to spare the dV for when it drags at you.

Edited May 17, 2019 by JadeOfMaar

[Laie]

7 hours ago, RocketSquid said:

Does a standard reentry profile (with a lander, not a space plane) need a heat shield?

Most parts can withstand 2000K and those will be fine, even if you do a direct landing from interplanetary. 1200K solar panels or batteries might be at risk.

If you need any kind of protection at all, a windscreen will do. A proper ablative heat shield will be overkill.

[Foxster]

It's the only place I use drogue chutes. Otherwise there is the risk of your craft not aerobraking enough for the main chutes to open. 

For lifting off the surface you can pretty much treat it as airless i.e. crank your gravity turn steep and not worry much about drag. 

[Reactordrone]

A normal Hohmann transfer from Kerbin usually doesn't get you fast enough to need heat shielding for aerocapture but a high speed transfer can. As with other atmospheres it comes down to entry speed.

[Adenosine Triphospate]

In almost all circumstances, no.

In my experience, coming from Kerbin, an aerodynamically stable craft will be fine with no heatshield (do remember to retract antenna and panels though). Entering into an eccentric orbit from kerbin takes very little delta-v due to Kerbin being not very far in terms of orbit. A 25km periapsis is a good height.

Coming from somewhere with a higher orbit (e.g Jool) means you will be coming in at a much faster speed, therefore more likely to overheat, but why would you do that?

Sub-orbital re-entry is even more forgiving, just remember to use sufficient (read: a LOT of) parachutes to land, if you want to avoid suicide burns.