If maneuver takes a 5m burn, should I burn to target or prograde?

[Oddible]

Say I have a very long interplanetary transfer prograde burn that takes over 5 minutes. Should I be burning to prograde the entire burn or should I be burning to the target set up by my maneuver node on the nav ball?

[Khan_Tiger]

What I tend to do is start the burn so that about half completes before you've reached the node marked, and keep things on target that way. Theoretically, if you burn perfectly toward the maneuver node marker and get the exact change in ÃŽâ€v that it tells you to, your new course will perfectly match the one the maneuver showed.

[Dave Kerbin]

Toward the blue maneuver node. If you know how long the burn will take then it is suggested to start it half way before the listed time - so a 5 minute burn would be started at T-2:30 and end at T+2:30.

[Sirine]

1st. Avoid long burn time.

2nd. Plan more maneuver node on the course. To re-correct you heading.

3rd. Put more engines, do asparagus staging in space. The lesser your mass the faster you go.

[Oddible]

1st. Avoid long burn time.

2nd. Plan more maneuver node on the course. To re-correct you heading.

3rd. Put more engines, do asparagus staging in space. The lesser your mass the faster you go.

How long is considered a "long burn time"? To Duna for instance. It is a 1081m/s dV burn with a LV-N, is that considered long?

[SaturnV]

Depends on your trajector, if you are on LKO, 5 minutes later you have moved 600km away, your prograde is changed like 5 degree, that will result as big different between the real after-burn trajectory and the one you planned on the maneuver

[LeFudge]

Anything over 4 mins i'll split into two burns, the closer you are to the Pe the more fuel you'll save. Also in case you didn't know ALT + . will let you time warp while the engines are burning, really helpful for those loooong LVN burns.

[kahlzun]

afaik, as long as you stay prograde te\he whole time, its the same?

[TechnicalK3rbal]

1st. Avoid long burn time.

2nd. Plan more maneuver node on the course. To re-correct you heading.

3rd. Put more engines, do asparagus staging in space. The lesser your mass the faster you go.

No offense, but this is completely WRONG. If yo do one larger burn closer to the beginning, it is far more efficient than several smaller burns. Also, always point at the maneuver node marker, unless you really, really know what your doing...in which case you wouldn't be asking this question, so just point the rocket at the maneuver node marker.

[relin]

Toward the blue maneuver node. If you know how long the burn will take then it is suggested to start it half way before the listed time - so a 5 minute burn would be started at T-2:30 and end at T+2:30.

What he said. There's nothing wrong with starting your burn early.

Now, if you're trying to make interplanetary burns with an ion engine, you might wanna split it into several smaller burns to progressively increase your Ap and Pe, but that's for those of us who don't mind 1h+ burns (because we're watching hockey anyway )

[Sirine]

How long is considered a "long burn time"? To Duna for instance. It is a 1081m/s dV burn with a LV-N, is that considered long?

for me, 3 minutes is a long burn.

Just recommendation.

1) (LV-N x4), in Kerbin SOI (Sphere of Influence). (Yeah, I know wasting some Delta-V, but who care, my "real-time" is far more valuable than the Delta-V).

2) Drop (LV-N x2) once you feel that you don't need that much power anymore. Thats 10 tons lighter. (Just do some innovating placement so the LV-N can be drop).

3) Do asparagus staging for your fuel tank. Don't carry too much "dry empty tank around". Split large tank to smaller size. (Same fuel capacity, but once drop, you can tell the difference.)

[Sirine]

No offense, but this is completely WRONG. If yo do one larger burn closer to the beginning, it is far more efficient than several smaller burns. Also, always point at the maneuver node marker, unless you really, really know what your doing...in which case you wouldn't be asking this question, so just point the rocket at the maneuver node marker.

Non-taken. You have your right to speak what you want. There is no right or wrong due to each definition, understanding is difference...example efficient.

Your point of view for efficient, surely differ with mine.