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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known solution to 1621 kg. Based on comparing the eight known low-thrust final masses<br />
to their corresponding impulsive optimal solutions, the multiplication factor must be<br />
increased again, to a value of 1.096.<br />
Optimal Impulsive Mf (kg)<br />
Optimal Impulsive Mf (kg)<br />
2000<br />
1800<br />
1600<br />
1400<br />
1200<br />
Earth-Ast.1<br />
1000<br />
0 5 10<br />
Asteroid Sequence #<br />
Earth-Ast.1-Ast.2-Ast.3<br />
2000<br />
1800<br />
1600<br />
1400<br />
1200<br />
1000<br />
0 5000 10000<br />
Asteroid Sequence #<br />
Optimal Impulsive Mf (kg)<br />
Optimal Impulsive Mf (kg)<br />
2000<br />
1800<br />
1600<br />
1400<br />
1200<br />
Earth-Ast.1-Ast.2<br />
1000<br />
0 100 200<br />
Asteroid Sequence #<br />
Earth-Ast.1-Ast.2-Ast.3-Earth<br />
2000<br />
1800<br />
1600<br />
1400<br />
1200<br />
1000<br />
0 5000 10000<br />
Asteroid Sequence #<br />
Figure 47: Branch-<strong>and</strong>-bound results, iteration #2 (impulsive multiplier = 1.077).<br />
Figure 48 plots the results of the third iteration. Nine additional low-thrust optima<br />
are computed during this iteration. The best known solution, however, is not improved<br />
upon. Furthermore, the impulsive multiplier does not have to be updated, as it is<br />
sufficient to bound all of the known low-thrust solutions. There<strong>for</strong>e, the branch-<strong>and</strong>bound<br />
algorithm is considered converged after three iterations, with a final impulsive<br />
multiplier of 1.096 <strong>and</strong> a best low-thrust final mass of 1621 kg.<br />
112