Hello! Question about longer interplanetary burns

[pleonasm]

Hello everyone! I am new to the KSP forums and have been playing KSP (a little obsessively) for a while now. I feel I've mastered docking and landing on Kerban's moons and I am starting to get into interplanetary travel. I had a question regarding the interplanetary burns. I'm supposed to burn prograde at the right ejection angle (which is no problem) but as the burn goes on, the actual prograde vector in the navball strays away from where I'm pointing. The question is, should I be changing direction to follow it during the burn or not?

[Supernovy]

If you think about it, staying on prograde while it changes will get you the most velocity increase for your burn, but staying pointing the same way will change the direction of the velocity slightly as well as increasing speed.

I'd say compare the manoeuvre node orbit to your actual orbit - if they diverge significantly, point at the node marker, but if they're almost the same, point prograde.

Also, Welcome to the community!

[MajorThomas]

Welcome!

I'd suggest:

1. Time it such that you do half your burn before you reach the "node" and the second half of your burn after the node. This gives me best results. For instance, for a 2 minute burn, start your burn one minute before the node, and keep going for 2 minutes.

2. Yes, chase the blue vector as it moves away at the end of the burn. But do it carefully...cut thrust and repoint yourself, rather than do it at full thrust. That little bit of vector wobble at the end is what I think of as the "residual" and gives you a chance to correct the error introduced by being pointed off the vector slightly during the main burn.

[Shna_na]

I recommend using maneuver nodes to get the result you want and following that node (the blue one) and burning until the Delta V needed for the burn is at 0.0m/s. Best results for me.

[SRV Ron]

Split the burn time and start at half the time before the node is reached continuing until the burn is complete.

For burn times over 2 minutes, usually when using an LV-N on a heavy payload when orbiting Kerbal, ignore the Add Maneuver marker and keep the rocket prograde at all times. If over six minutes, you are better off doing several burns at paragee to reach escape velocity. You will have to watch what is happening to your actual course since what the Add Maneuver Mode shows will become meaningless.

For interplanetary maneuvers, when outside the influence of a planet's SOI, do the long burn as normal.

[fastbikkel]

Feel welcome!

But this question should have been in another part of this site.

Anyway, it is good you found KSP and this site, both are great.

[Vanamonde]

But this question should have been in another part of this site.

Newbies are often too bashful to ask their questions on the main forum for fear of bothering more experienced players, so the Welcome sub-forum is a bit looser about that sort of thing.