Lander Reentry Help

[Red Shirt]

My first post. I have been playing for 1 1/2 years. In that time I have landed and returned from Moho before I knew it was hard. Drove a rover into the Dres canyon. While it did not end well, the point is I am not a complete beginner. That said, I went from 0.90 to 1.04. Launched the Kerbal X stock ship for a test run. It went easily in 100k orbit. Then I tried to return to KSP with the lander stage. The ship did not attempt to slow at all. It just turned to toast before disintegrating. I slapped Mechjeb on it and tried again. Same result. So if Mechjeb can’t reenter a lander in 1.04, how do I? I tried lowering my Pe to 30k for a shallower angle. Still too hot. I finally pulled the heat slider down to keep the game fun, but seriously, how do I get this lander down with 100% heat?

Edited July 6, 2015 by Red Shirt

[SoWeMeetAgain]

at the moment... thermal control thingies, the stationary ones, they soak up aaaaall the heat

set periapsis to ~30km on kerbin,, should give you enough time to slow

really heavy craft, as you can see almost no fuel left, mostly the "natural" air resistance and nothing(!) exploded or even got really critically hot

Edited July 4, 2015 by SoWeMeetAgain

[Gaarst]

Please post screenshots of your lander.

Though heat has changed a lot with 1.0 and later 1.0.4, it is still very feasible to reenter a ship from LKO without heatshields or radiators, even at 100% reentry heat. You don't even need to make your reentry that shallow.

Did you install 1.0.4 over 0.90 or did you make a completely new game folder ?

If you did the first option, then some config files may conflict and change heat behaviour.

Edited July 4, 2015 by Gaarst

[Jaeleth]

try around 50k, 30k is not shallow. Anyway, it shouldn't be burning that way unless something is wrong like Gaarst mentioned

[Chaos_Klaus]

KerbalX has no heatshield? Because with a heatshield you can out your pe at 30km coming from minmus, no problem.

Engines also can take a lot of heat. You need to reenter "backwards" with the capsule pointing retrograde.

[Reactordrone]

I've successfully brought the kerbal X lander back from the Mun in 1.0.4 so it's definitely possible with a shallow re-entry, periapsis of around 35-40km. You also have to get out of the 0.25/0.90 money saving habit of bringing the whole ship back and just land the capsule.

Having said that, the drag setup of the capsules is much lower than in real life which is why they're coming in too fast and hitting the insta-death heat wall at around 15km.

[Snark]

I find that as long as I keep the approach shallow (periapsis up around 30-35 km), there's no problem. From LKO, no heat shield required. Coming home from Mun or Minmus, even a little bit of heat shielding is ample.

Aside from keeping the approach shallow, you also want to maximize your drag while still in the upper atmosphere where heating isn't dangerous. The best and easiest way to do this is with airbrakes; they're cheap, light, and incredibly effective (way overpowered, IMHO). Even without airbrakes, you can help by angling your ship to the draggiest attitude possible, e.g. sideways, and hold that until you get down to 35-38 km before rotating to put your heat resistant parts forward.

[Red Shirt]

First chance to respond since posting. The ship is the Kerbal X stock ship that came with the game. The lander portion is a poodle engine on a Rockomax X200-16 tank with landing gear, a decoupler and a MK1-2 command pod with chute. It weighs 16t. If I can't land this accurately without burning up on Kerbin, I'm wasting my time trying to land on Laythe. Reentry with just the pod is out of the question. This morning I slapped 3 airbrakes on the tank. Mechjeb behaves oddly with airbrakes in upper atmosphere and never attempts to use them as the heat goes lethal. I manually braked and did slow down enough to land but fell short of the target by 22k. So yeah, I finally got down safely but lacked precision. With the tiny amount of landing area on Laythe I am going to have to do better.

If this is the new normal, there really needs to be a tutorial for successful reentry including help with the parts needed. Most beginners are going to lose interest in a hurry if they can't land.

I like to use Mechjeb when I need precision landing as I stink at hitting KSP on my own. It worked in the past but appears incapable of working with the new aero and heat. Am I correct or am I using it wrong.

[GoSlash27]

I have reentered fragile assemblies without heat shields from as far away as Minmus without damaging them. The trick is patience.

Set your periapsis to 50km to gently aerobrake without overheating. It will take several passes to bleed off the excess speed.

Gradually (and carefully!!) lower your periapsis over successive passes for more effective braking.

Your final reentry pass should have a periapsis not lower than 45km.

You can get more aggressive with heat shields, but I still wouldn't shoot lower than 40km.

Best,

-Slashy

[Red Shirt]

Everyone is saying the same thing, so it appears it is just me not getting it. Using Mechjeb, I am entering the atmosphere at about 2.2k and the craft picks up speed to nearly 3k at around 12km where it overheats and blows. I'll check my speeds again using 30k Pe and no Mechjeb. Don't recall it being much better.

[Kryxal]

My usual passes are at 38-40 km and scrub off a few hundred delta-v each time, facing retrograde. If I want to adjust my next pass, I can face prograde and pitch up or down (pitching DOWN past periapsis actually raises your periapsis for the next pass, if you can manage it, but before periapsis you need to pitch UP).

[Red Shirt]

OK, I'm going to change this to answered. This morning I removed the airbrakes, I used last time, and added 3 small radiator panels and 3 radial chutes. Using Mechjeb to make sure it was not me messing things up, the lander set down 2.8k north of KSP. Not entirely accurate but hey, the ship did not explode.

I could see the monolith while descending but it disappeared before touchdown. Is it below grade now?