Pinpoint reentry?

[Gabe]

I was reading HarvesteR's Dev Blag, Rethinking the way flights end, and was intrigued by this: "The plan is to add an option to 'Recover' a vessel whenever possible. Recovering a vessel would return you some of its value, giving an incentive to build reusable vessels. Of course, recovering would only be possible for vessels landed or splashed down on Kerbin, and the value of the recovered vessel would vary based on how far from KSC it actually is."

I wanted to start practicing landing as close as possible to the Space Center. Which brings me to my question: How is the best non-mechjeb way to re-enter Kerbin and land as close as possible to the Space Center? I personally prefer to become manually proficient at a task first and then let mechjeb start doing it for me when it become a boring grind.

How much does vehicle drag, mass and angle of entry affect precision landings on Kerbin? Can I always reenter at the same window or will it vary by what I'm flying and/or how fast I'm coming in?

[Sephta]

Your best bet:

Place a maneuver node and place the landing quite a bit east from KSC (for the drag.) Remember how far east you were and start decending. If you go down too far in one direction, adjust your node. Rest is practice.

Keep in Mind, it works totally different for Spaceplanes (depending on how many fuel you bring back), as they tend to glide much longer in the atmosphere and you usually don't go backwards with them...

[bsalis]

Rest is practice.

Yeah, basically that. If you set a known circular orbit, say 100Km. Then at a certain point above the ground, looking at features, do a burn to set your trajectory a certain distance east of KSC. Then you should always land about the same place. Practice should tune that to be over KSC.

That, or spaceplanes.

[capi3101]

You're going to want to aim about 75 degrees ahead of the KSC and put the periapsis all the way to the ground, IIRC. Somebody had a thread on this topic not too long ago with some nice charts. They might've been added to one of the stickys at the top of the forum; I don't know. Wish I could be more helpful to be honest.

If you need a marker for the KSC, build a "ship" consisting of a Mk-I lander can. Launch it. Have the Kerbal inside go EVA, walk all the way off the launch pad circle (or pick him up with a rover at the KSC), and plant a flag. That'll give you a nice ground navigational reference. Just don't put it in the runway, the taxiway or the road from the VAB to the launchpad; flags planted there have a tendency to explode...

[Spaceisbeautifulul]

I usually like to practice targeted reentry using spaceplanes.

Mostly because they have cross-range capability. So if I miss I can keep going.

It really does depend on the body though, how fast its spinning, how big it is, atmospheric drag, etc, etc.

Just keep tryin' though.

[Motokid600]

Space planes are easy. You can deorbit whenever over KSC and just fly back. Landing right on the runway is a bit hard though. ( not if u have a real well built plane ) What I did was I set a marker like capi said. I took it a little farther though. I used 3 small rovers. Because not only did I want to see where KSC was from orbit I want to see which way the runway is facing as I descend. So I park one probe at the beach lined up with the runway. Then the second is parked out past the runway about a 100 meters. And finally the last rover is parked way out west about the length of the runway. So now I have 3 evenly spaced markers I can see from orbit drawing a straight line right over the runway. Best thing I've done to help me fly home.

As for anything else its trial and error. If your looking down on the north pole and KSC is at 6 o clock I start my deorbit burn at about 8 o clock. I usually shoot for a 100km orbit so I set the nodes trajectory in the center of that sea past KSC to account for drag and planet rotation. Now this is where the skill comes in. The best thing you can hope for is a hole in one after your deorbit burn. I have yet to accomplish that. I usually put small radial engines on so that I can adjust as I'm coming in. I tend to under shoot KSC alot. So I have to make a last minute burn to get me closer. Don't under estimate drag. If you've already burned through rentry and your skeptical if your gonna overshoot into the water.. your not. Horizontal velocity gets scrubbed off very quick. Especially if you pull your parachutes. Which in case if you know for a fact that your gonna over shoot you can pull them early to kill your velocity and start falling down straight. I try to not open my chutes until a few thousand meters and let the air kill my speed. Best landing I've managed was right at the end of the runway.

This is cool because I was just talking how it'd be great to have some sort of building to bring the landers too that actually "completes the mission" Menu music plays, awards, medals, hurrah! Lol...instead of just manually ending the mission and role playing. I already have a nice truck/crane that runs out and brings my landers back. Be cool to make a VTOL to pick them up out of the water in case of a splash down.

Edited June 17, 2013 by Motokid600

[Diche Bach]

Here is the thread that was mentioned above with the charts and such. Great stuff!

http://forum.kerbalspaceprogram.com/showthread.php/37327-Atmospheric-Landing-Chart-Pinpoint-landings-on-Duna-Eve-Kerbin-Laythe!

[Frederf]

Certain profiles are horribly sensitive to initial parameters so avoid those as much as the equipment and mission will allow. A gentle capture over several orbits can turn 100mm/s (note: millimeter) velocity anomaly into a wide splashdown error.