Ok, so I am rather confused, but first things first, here is the situation:
Low TWR (0.21 in LKO when fully fueled) 2-part rocket assembled in space. KER says it has 4,800 m/s dV.
TriggerAU's launch window planner's estimate dV for an encounter with my target: 2,399 m/s
My maneuver: 2,444 m/s, off the top of my head the game tells me it's supposed to be somewhere between 16 and 19 minutes of burn.
Impossible to do in one pass, my periapsis drops within atmosphere, best I managed was to cut roughly 1/3 of the burn before I reach escape velocity
I did that in 3 burns of about 2 minutes, one minute before the node and one minute after.
New maneuver that takes me to my target: 1,400 m/s with about 3,200 m/s left according to KER (net loss of 200 m/s? due to..?)
Performing the remainder of the burn in one pass due to escape velocity: just under 10 minutes, burning 4:45 before the maneuver leaves me with 1,875 m/s (another loss of 375 m/s???)
So, I'm not used to low TWR rockets, I usually stick with 0.5 or greater. Is it normal that there is wasted dV due to not performing burns as precisely as one would with greater TWR? Is it KER that's lying to me? Or am I approaching long interplanetary burns wrong? How do you deal with long burns? I have been using physics acceleration, has that been known to fudge things? Because I just don't get why I would end up using about 30% more fuel according to KER compared to what maneuver nodes tell me. That's a rather disconcertingly large margin of error.
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Ok, so I am rather confused, but first things first, here is the situation:
So, I'm not used to low TWR rockets, I usually stick with 0.5 or greater. Is it normal that there is wasted dV due to not performing burns as precisely as one would with greater TWR? Is it KER that's lying to me? Or am I approaching long interplanetary burns wrong? How do you deal with long burns? I have been using physics acceleration, has that been known to fudge things? Because I just don't get why I would end up using about 30% more fuel according to KER compared to what maneuver nodes tell me. That's a rather disconcertingly large margin of error.
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