a better way to do long burns?

[Laie]

I have at times broken up looooong burns into several smaller ones, and started to wonder if there is a better way.

First, am I right to believe that the best way of moving in space would be

1. point ship in (direction)
   
2. wait until you're at the right position
   
3. open throttle, lock the rudder, and wait until done
   
4. ?
   

Second, how do I find the right direction, and the right position to start the burn? What's a meaningful way to express that direction, anyway -- n degrees normal of prograde, perhaps?

[Mesons]

I've wondered the same thing before, and the conclusion I have come to is to improve your TWR and make the burns not so long. It does change the design phase a lot, though...puts a bit more weight on it.

The coordinate system you suggested for specifying the angle works great, and from prograde/retrograde towards normal/antinormal and towards radial/antiradial is a very natural way to express the direction. Your example would be 0 degrees radial and n degrees normal of prograde, for instance (to fully specify).

[MarvinKitFox]

loooong burn.

Figure time & place & direction.

Go there/then.

max thrust. alt >>>>

watch a youtube funny. Keep KSP sound on, to hear if something weird happens. Look in every couple minutes, to make sure direction is good.

My longest burn ever was lining up for a Kerbol flyby.. 22000m/s , with a TWR of 0.006

I got to watch Star Wars, waiting for the burn to finish.

.

all of em!

[von Ziegendorf]

Here is something that might partially solve your concerns Long Burn Calculator

[Kasuha]

When breaking the burn to smaller pieces:

- best done if you use ballistic transfer as you have instant verification in the form of intercept of your target

- set up the maneuver (and check you get intercept)

- start burning reasonable time ahead

- continue burning until there is periapsis at your maneuver. Then kill the thrust, delete the maneuver, and set up a new one at that periapsis. Again, you should get an intercept for verification you did it right

- do not go behind about Mun's orbit in your partial burns. You won't save that much dv and it'll take LONG time to go around, you may miss your transfer window

When doing just one or final burn (even with divided burns, the last burn may be over half of the total dv)

- set up the maneuver (again, it's good to have verification in the form of intercept)

- start burning reasonable time ahead

- when you're nearest the original maneuver (you'll go below it), fix your heading according to the maneuver indicator. After that, keep your heading.

- it is good if you have periapsis above 100 km since your heading will not get skewed by Kerbin's rotation (rotational frame is below 100 km)

- as you're getting near the maneuver, switch to map view and watch your trajectory vs planned trajectory. Make corrections (subtle changes in heading) so the two SOI ejection points get near each other. You also need their timestamps (mouse over them) to match.

- when you got enough, delete the maneuver and set up a new one (correction) sufficient time ahead. By that time you left most of Oberth behind you so it's not critical anymore.

[Laie]

Figure time & place & direction.

Go there/then.

max thrust. alt >>>>

Well, now to the fun part: how do I figure the time&place and direction?

@vonZiegendorf: your calculator isn't quite what I'm looking for. It's similar enough to get me all excited, but ultimately not helping. More in your thread.

[Laie]

Hmmm. Coming to think of it, if I launched into a properly-inclined orbit, i could probably forego a good part of the normal component and burn mostly prograde. But how do I find the right inclination?

[Kasuha]

Hmmm. Coming to think of it, if I launched into a properly-inclined orbit, i could probably forego a good part of the normal component and burn mostly prograde. But how do I find the right inclination?

Try Alexmoon's calculator.

[Reactordrone]

Well, now to the fun part: how do I figure the time&place and direction?

Manoeuvre nodes.