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Post by harlikwin on Sept 25, 2016 14:20:27 GMT
So this mission has one trying to take out a laser frigate in an out of plane retrograde orbit. The various briefing materials suggest that the best way to deal with this is to burn your force into a retrograde orbit, and that the best way to do this is to burn at the periapsis (low point of the orbit to take advantage of the oberth effect). However when I try this there is almost enough DV to do it but its short by a few hundred m/s I.e. there isn't enough DV to even make a retrograde orbit, much less match planes with the target. I assume that if I try a plane change at the same time as the retrograde maneuver that would save some DV for the plane change (yay for all those orbital mechanics I learned playing KSP).
Any thoughts on this, am I doing it wrong?
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Post by pokington on Sept 25, 2016 14:39:18 GMT
Inclination changes are a LOT more efficient at higher orbits.
A bielliptic transfer is a much, much more efficient way to put yourself into a retrograde orbit, and works pretty well in that mission provided you don't go too high.
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Post by harlikwin on Sept 25, 2016 14:57:55 GMT
So, I had to google bi-eleptic transfer (hey KSP is simple compared to this). So my main issue is not having enough DV to go retrograde in the starting circular orbit, and I'm not sure what you are suggesting. Are you saying to get into a higher orbit first and then go retrograde? Do i still burn retrograde at periaps?
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Post by argonbalt on Sept 25, 2016 15:34:07 GMT
So, I had to google bi-eleptic transfer (hey KSP is simple compared to this). So my main issue is not having enough DV to go retrograde in the starting circular orbit, and I'm not sure what you are suggesting. Are you saying to get into a higher orbit first and then go retrograde? Do i still burn retrograde at periaps? Yes remember that the closer you are to a body the higher the gravity "tax" you need to pay to move, unless you are continuing a burn in the same direction as a majority of your velocity is already moving (presumably through the periapsis of the orbit of a body). So if you wanted to hit a retrograde target that is also near the planet, you would instead burn to an ellipse, then at apoapsis, burn your retrograde movement to turn your orbit retrograde. Even though it sounds like you are doing more, it is a far cheaper way of getting to the target. |
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Post by pokington on Sept 25, 2016 17:48:23 GMT
FWIW, bielliptic transfers in Kerbal are only really useful for reversing your orbit anyway, so you don't end up doing them very often, since you generally either launch or capture into the correct inclination. You need to do something like this (click me for a picture!). You do a prograde burn into a higher orbit, then reverse your orbit high up. If you do it as you cross the enemy's orbital plane you can also do the inclination change simultaneously. Here it only took about half my DV, and now I can launch drones and missiles with impunity or phase my orbit for an intercept. |
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Post by harlikwin on Sept 25, 2016 19:17:25 GMT
Thanks Pokington, I managed to get it work, Unfortunately, I managed to time it just right so I intercepted the frigate with both ships, my carrier got chewed up pretty bad, but I still managed to win.
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