Re-entry disconnecting the command module and parachute

[Olsson]

Hello,

I\'ve just learned how getting into orbits work (thanks to you guys <3) and I\'ve been able to become sufficient enough to pin-point an exact landing site. Though when I disconnect my last stage with one fuel tank and a rocket into a command module with parachute my trajectory towards the earth changes since the mass has changed. Also opening the parachute also changes my trajectory. My question is:

- How does one pick their landing site using a rocket and then disconnect the command module and continue heading towards that state?

- Does rotating the command module do anything?

- The parachute also changes my trajectory, how should I use it to make sure I hit that perfect landing spot?

[Asmosdeus]

Point the vessel at the landing spot when you decouple and it shouldn\'t change the landing spot too much, as for the parachute, deploy it when you\'re in a vertical fall towards your landing spot.

Personally I prefer to just aim for the ocean.

[what-the]

The easiest way to land somewhere near the spot that you want, is to obtain a low (circular) orbit which passes over the place where you want to land (I recommend 100km for Kerbin and 25km for the Mun). When you\'re ready to land wait until just before you go over the landing site in your orbit and thrust towards that yellow circle with an x in it. Don\'t follow the x as it moves up, you want to cut almost all horizontal velocity (For the Mun I leave about 50m/s horizontal velocity). As you descend look down until your right over your landing spot and remove the rest of your horizontal velocity. Also make sure you switch to surface mode before burning.

Using this method answers your questions as follows.

-This method lets you descend straight down at a low initial velocity. Atmosphere has no influence on where you land (unless there is wind but there is none at the moment).

-Rotating the command module does nothing unless it is touching something external. i.e. ground

-The parachute will not change the landing spot using this method.

[PakledHostage]

And once you master that method, you could strive for higher efficiency re-entries that still get you close to your target. I\'ve brought my capsule down at KSC from a 100 km high orbit using only 82 m/s Delta V. It is possible to do it with even less Delta V than that.

Check out the Mercury 'Friendship 7' Commemorative Challenge. I included retro-fire timing and Delta V values there for three different starting orbits (you have to click on the spoilers to see them).

PH.

[samstarman5]

The easiest way to land somewhere near the spot that you want, is to obtain a low (circular) orbit which passes over the place where you want to land (I recommend 100km for Kerbin and 25km for the Mun). When you\'re ready to land wait until just before you go over the landing site in your orbit and thrust towards that yellow circle with an x in it. Don\'t follow the x as it moves up, you want to cut almost all horizontal velocity (For the Mun I leave about 50m/s horizontal velocity). As you descend look down until your right over your landing spot and remove the rest of your horizontal velocity. Also make sure you switch to surface mode before burning.

Using this method answers your questions as follows.

-This method lets you descend straight down at a low initial velocity. Atmosphere has no influence on where you land (unless there is wind but there is none at the moment).

-Rotating the command module does nothing unless it is touching something external. i.e. ground

-The parachute will not change the landing spot using this method.

That tactic works just fine now, but when heat reentry mechanics are implemented, that will be considered too steep a drop and you will get to watch your craft disintegrate into many little burning marshmallows.

[what-the]

That tactic works just fine now, but when heat reentry mechanics are implemented, that will be considered too steep a drop and you will get to watch your craft disintegrate into many little burning marshmallows.

That actually depends. Because the re-entry hight is low and re-entry speed is low (Circular orbit will have no vertical velocity to start with) it probably won\'t burn up. It\'s kind of like those high altitude hobby balloons that burst they don\'t burn up.

[Olsson]

If not using the method above because it might not work with reentry heat. Is there any other way to calculate or just to know where I\'ll end up. Because the atmosphere slows you down upon re-entry so you don\'t follow the orbit before entering since it slows down and becomes smaller, you have to guess because of this where you\'ll end up. Also activating the chute will slow you down further.

It\'s like a guessing game but if anyone know the calculations or better method (apart from the one above that probably wont work with re-entry) for getting a more precise splash down?

[Joe Pinball]

I don\'t know any better calculations, but the AR202 ascent computer does! (can be got from the plugin forum section)

It features a 'landing computer' which will calculate the co-ordinates of where you are (very likely) to land: set it to target KSC and then you can fine-tune your trajectory as you begin to re-enter atmo for a pinpoint landing on the KSC every time, only ejecting the last rocket stage as you are almost upon the KSC.

Worth a try imho

Joe 8)

[Olsson]

Joe: Wow that sounds really sweet I\'ll be sure to check that out.

EDIT: Meh the AR202 is still a guessing game, I don\'t see how it differs from the actual ingame landing system. The only difference is that it\'s made simpler by having pre-set orientations and approximate landing coordinations on the window. Though I don\'t know how to read these coordinates on the map and they change more when I open my chute.

But then again if this computer takes into account of the slow down speed of the atmosphere it makes the landing more predictable. But it doesn\'t take this account on the orbit instead it does that on the coordinates and I don\'t know how to read them.