Most Efficient Way To Launch A Satellite?

[The Flying Kerbal]

OK guys, a little advice needed here.

When launching satellites, is it more efficient to push the Ap out first, better to push out the Pe first, or when the orbit has been completed as specified in the contract will it have made any difference?

I suppose when both Ap and Pe are pretty close if there is some Dv to be saved it wouldn't be all that much, but with a contract I've just picked up the orbit is 15,280,053 x 3,457,679 with an inclination of 11.5 degrees.  Normally my parking orbits are on the low side - around 72.5 Km and very rarely over 75 Km - and I usually push the Ap out first, then adjusting the inclination on the way up to the Ap when I reach one of the nodes.

This works for me, but if there is a more fuel efficient way of doing it, I would appreciate if someone could point me in the right direction.

Thanks everyone.

[bewing]

Yup, pushing the Ap out first maximizes the oberth for that burn, and also minimizes the deltaV of your inclination burn. Those are your two biggest costs. After that, there are no more savings to be found.

 

[Superfluous J]

What bewing said, but to add a point:

When you are low burning up, it costs X m/s to burn up to Pe level, and Y to burn from there to Ap. Y will frequently be surprisingly low even for very different Pe and Ap values. Try it with maneuver nodes and see. This is Oberth helping you. When you are then at that Ap, it costs Z m/s to raise your Pe to the target Pe. That target Pe is low so your current Pe is close to it, so it's not that much of a burn.

If instead you burn your Ap to the target Pe, you only do the X burn and "save" having to burn the Y burn. However, when you are at your new Ap (which is the target Pe) you'll then have to burn... Oh I ran out of letters. Uh... W, to get your Pe all the way up to the Ap. Without Oberth's help, that burn will be MORE than the Y+Z you would have had to burn in the first instance.

I would draw a diagram but I'm kinda busy.

Edited July 4, 2018 by 5thHorseman
Yay for swype correcting "bewing" to "being"

[The Flying Kerbal]

Two great answers guys, and now I know I'm doing things in a not totally incorrect manner.  thanks for taking the time to answer.

[Xd the great]

For a orbit, you need height and you need lateral velocity.

The longer you fight gravity, ie burn up , the more fuel you waste. 

The longer you fight atmo drag, the more fuel you waste.

So the best combination is to burn up at first, then slowly turn sideways. The rate of turning depends on a lot of math and physics that i do not understand or know.