Falling too fast to Kerbin after coming from the Mun

[Zyrius]

Whenever I come back from a Munar landing, the craft doesn't start to burn in the atmosphere until ~10000 meters, and by then I'm still going at ~2000m/s. How do I fix this?

Edited November 1, 2015 by Zyrius

[uncle_jew]

Don't aim for the Kerbin surface - your trajectory should only "touch" the Kerbin atmosphere. The indicated apoapsis at Kerbin should be between 24-30km.

Also, make sure the cross section of the lander is big enough (e.g. if you try landing a long thin object pointing retrograde - it will not decelerate fast enough). For the first landing attempt, maybe just try landing the capsule with an attached heatshield and a parachute (detach everything else with a decoupler prior to entering the atmosphere).

[ForScience6686]

You want to bleed off speed in the upper atmosphere. The lower you go, the thicker the atmosphere, the faster the heating.

[Snark]

Agreed. Previous responder suggested a periapsis of 24-30km, I'd suggest right around 30km to play it safe until you get the hang of it better. 30 km is high enough to be fairly safe at munar return speeds, but low enough that you're unlikely to go skipping out of the atmosphere and come round again.

[Sovek]

Amazing you arn't burning up. I play around with Kscale 2 and direct munar re-entries are.... harrowing. 4.5km/s re-entry. I can actually get away with a 40km Pe without skipping back out. My lowest I've ever gone is 25km but its pushing the g-force and heat a bit too high for my tastes.

But yes, aim for a higher Pe. The longer you are in the upper atmosphere, the faster you slow down, unless you have a a long pointy missile, then it aint gonna slow down very fast.

[Shark4558]

Well, my advice would be that when you return from the Mun, try aiming at a periapsis of 37 Km, and point Retrograde during Re-entry, if the speed is too high in the Pe use the rockets to stop faster.

[RA3236]

Whenever I come back from a Munar landing, the craft doesn't start to burn in the atmosphere until ~10000 meters, and by then I'm still going at ~2000m/s. How do I fix this?

Unless you typed wrong, or I cannot read, you have a problem with your install. Reinstall KSP and if this still happens make sure you have a Physics.cfg file in the install. (of course, only if you are doing what everyone else is doing)

If I read wrong, I agree with everyone else. Aim for a 30km Pe and bleed off speed USING A HEATSHIELD. That's the most common over heating problem.

[celem]

You could also deliberately make a multi-pass reentry. Coming in from the Mun i'll often take about 38km which slows you down over 2 or 3 passes, just make sure the payload has enough battery and control to orient through multiple passes.

Failing that, airbrakes on the tail will also let you dump some speed.

I agree that no burning till 10km sounds wrong, you should be roasting from 35ish on down, doubly so if coming in steep.

I will say that I dont use a heatshield on the Mk I pod, it has one built-in, however as soon as you bring down more than just the pod you will need the extra one to cover the new bottom face. I'll often aerobrake with my engines pointing retrograde, fire off their remaining fuel at periapsis to help speed things up and then ditch to let the pod come down alone after popping back out of the atmosphere once or twice.

[RA3236]

You could also deliberately make a multi-pass reentry. Coming in from the Mun i'll often take about 38km which slows you down over 2 or 3 passes, just make sure the payload has enough battery and control to orient through multiple passes.

Failing that, airbrakes on the tail will also let you dump some speed.

I agree that no burning till 10km sounds wrong, you should be roasting from 35ish on down, doubly so if coming in steep.

I will say that I dont use a heatshield on the Mk I pod, it has one built-in, however as soon as you bring down more than just the pod you will need the extra one to cover the new bottom face. I'll often aerobrake with my engines pointing retrograde, fire off their remaining fuel at periapsis to help speed things up and then ditch to let the pod come down alone after popping back out of the atmosphere once or twice.

The mk1 pod does not have a heat shield.

[Nothalogh]

I usually aim for 35 to 40 km, and do a once around aerobrake.

Build your reentry vehicle to be aerodynamically stable in the retrograde orientation so that as soon as you cross 50km you self stabilize

[Zyrius]

So whay you guys are saying is to aim for less of a steep descend nad stay longer in the atmosphere?

Will try that out togight.

Thanks!

[ForScience6686]

Correct, you need the thinnest atmosphere to slow you down before the thick stuff. It's just air but when moving that fast there is a lot of friction generated on moving the air around the ship.

[zolotiyeruki]

I usually aim for 35 to 40 km, and do a once around aerobrake.

Build your reentry vehicle to be aerodynamically stable in the retrograde orientation so that as soon as you cross 50km you self stabilize

Same here--I aim for 38-40km, and if I skip off, it's no big deal. If I'm in a spaceplane, I try to use the lifting surfaces to keep me at that altitude at least until both Pe and Ap are within the atmosphere.