I worte a program in Vizzy, that can get most rockets into orbit. The problem is, if the rocket must stage, while the circularization burn is happening. Any ideas how to include this in the calculations?
Right now I'm using this equation: ((mVe)/f)(1-e^(-dV/Ve))
m - starting mass
Ve - effective exhaust velocity
f - thrust
dV - manuever deltaV
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4.8 years ago
@Kell now I understand what your program does, however this way the rocket ended up in a 120 - 90 km orbit, instead of the target 80 km. It is a simple solution, however its not really accurate.
BTW your program looks cool, and is quite universal. -
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4.8 years ago
@Kell this does not really solve the problem. Imagine you need 1000 DeltaV to circularize, the current stage has 500, and the stage after that has 2500. If I only burn the first stage, as your program would, I will not even get into orbit. If I ditch the first stage, I waste 500 deltaV. If I burn through both stages (as my program currently does), and TWR of the stages differs significantly, the burn will be very inaccurate. I'm looking for a solution, that takes into account the TWR difference of the two stages, as well as the time needed to stage and ignite the second engine.
I believe, KSP did it somehow with its manuever nodes, but it might use more information than you can currently read from Vizzy. -
40.7k KellyNyanbinary4.8 years ago
My program calculates the delta-v required to circularize, and if the current stage does not have enough delta-v, it will fire the stage until it burns out
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Why do you specify a certain amount of delta V for a specific maneuver? I tell the rocket what to do and that's what it should do. I know I don't do circularization the classic way (mine is easier but not used by space agencies) . It doesn't give more than couple of kilometers difference between apogee and perigee but it does crazy spin in process that I prefer to do it without first stage weight.