Optimal space plane re-entry trajectory

[merchant_mariner]

Its been exactly one year since I purchased KSP and today I finally flew my own custom built SSTO space plane into orbit! However, the landing was distinctly kerbal; I royally undershot KSC and Jeb ended up lithobraking into a hillside in the desert. So to avoid future spaceplane impactor experiments, what is the best re-entry trajectory to land spaceplanes back at KSC (Assuming a 100 x 100 orbit for simplicities sake).

[astropapi1]

I like to do my standard de-orbit operation: (It's a bit hard to explain, but I'll try) warp until you're on the other side of the korea-like peninsula of the planet, and then burn retrograde 'till your periapsis hits 30 km over it. If you're doing this with a plane, you might want to under-shoot it a bit so you can come in for a normal landing with jet engines.

Edited April 26, 2013 by astropapi1

[bsalis]

Is the problem getting the entry point right? Or controlling the craft after re-entry?

[merchant_mariner]

Problem is getting to the correct re-entry point. My space plane actually flew very well (just ran out of jet fuel trying to find some place flatish to land).

[GreenDragon]

30km above the desired landing point will get you close, planet rotates below you so aim a little ahead, since you dont want to overshoot aim a little lower and fly the rest of the way.

[capi3101]

30km above the desired landing point will get you close, planet rotates below you so aim a little ahead, since you dont want to overshoot aim a little lower and fly the rest of the way.

Does that apply to landers as well as planes? Closest I've ever gotten to the KSC in a lander has been 80 km so far.

[bsalis]

Problem is getting to the correct re-entry point.

Trial and error. You will get a feel for it soon enough. Try using quicksave & quickload to learn. generally your trajectory should be ahead of your target to account for rotation of Kerbin and aerobraking.

30km above the desired landing point will get you close, -snip-

30Km does seem to be a threshold between thin and thick atmo. Trajectory decays quickly under 30km. Above 30km you should be able to do rocket burns to fine-tune the descent. Once your below 30km you are sort-of locked in and should be pointing pro-grade.