design space pruning heuristics and global optimization method for ...
design space pruning heuristics and global optimization method for ...
design space pruning heuristics and global optimization method for ...
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<strong>pruning</strong> metric must be calculated <strong>for</strong> each possible asteroid pair in the <strong>design</strong> <strong>space</strong>.<br />
While this is not a problem <strong>for</strong> the small sample problem, it will become computationally<br />
intensive <strong>for</strong> significantly larger problems.<br />
Second, each <strong>pruning</strong> metric is still summed over all the legs <strong>for</strong> each sequence,<br />
but each metric is applied individually, in sequence. There<strong>for</strong>e, all of the asteroid<br />
sequences are first ranked as a function of θ wedge , summed over each of the legs. A userdefined<br />
percentage of sequences is then eliminated from the <strong>design</strong> <strong>space</strong>. Next, the<br />
remaining sequences are ranked as a function of the optimal phase-free, two-impulse ∆V,<br />
again summed over all the legs. A user-defined percentage of sequences is then<br />
eliminated from the <strong>design</strong> <strong>space</strong>. This approach requires less computation time, since<br />
the optimal ∆V needs to be computed <strong>for</strong> a smaller number of sequences. Figure 29 <strong>and</strong><br />
Figure 30 plot the optimal low-thrust final mass as a function of θBwedgeB <strong>and</strong> optimal<br />
phase-free, two-impulse ∆V, summed over all the legs <strong>for</strong> each asteroid sequence in the<br />
sample problem.<br />
Final Mass (kg)<br />
1000<br />
900<br />
800<br />
700<br />
600<br />
500<br />
400<br />
300<br />
200<br />
100<br />
0<br />
0 50 100 150 200<br />
Figure 29: Final mass as a function of θ wedge , summed over all legs <strong>for</strong> each asteroid sequence<br />
remaining in the small sample problem.<br />
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