design space pruning heuristics and global optimization method for ...

Figure 35: Low-thrust optima as a function of the normalized sum of the pruning metrics
(branch-and-bound ranking), for the small sample problem ...........................84
Figure 36 Set of asteroids for intermediate sample problem............................................94
Figure 37 Asteroid sequences remaining in design space after 1st pruning metric (blue)
and 2nd & 3rd pruning metrics (pink). ............................................................97
Figure 38 Maximum final mass for each asteroid pairing as a function of the angle
between the two angular momentum vectors...................................................98
Figure 39 Maximum final mass for each asteroid combination as a function of the
minimum, phase-free, two-impulse ∆V...........................................................98
Figure 40 Branch-and-bound tree enumerating all asteroid sequences remaining in the
intermediate sample problem after the pruning phase. ..................................100
Figure 41 Branch-and-bound tree illustrating asteroid sequences pruned out by the first
iteration of the branch-and-bound algorithm on the sample problem............100
Figure 42 Results of the 1st iteration of the branch-and-bound algorithm applied to the
intermediate sample problem.........................................................................101
Figure 43 Results of the 2nd iteration of the branch-and-bound algorithm applied to the
intermediate sample problem.........................................................................102
Figure 44 Asteroid sequences identified by applying branch-and-bound algorithm to
intermediate problem. ....................................................................................103
Figure 45 GTOC3 set of asteroids..................................................................................106
Figure 46 Branch-and-bound results, iteration #1 (impulsive multiplier = 1). ..............111
Figure 47 Branch-and-bound results, iteration #2 (impulsive multiplier = 1.077). .......112
Figure 48 Branch-and-bound results, iteration #3 (impulsive multiplier = 1.096). .......113
Figure 49 Comparison of optimum impulsive final mass (multiplied by 1.096) and
optimum low-thrust final mass for modified GTOC3 problem.....................115
Figure 50 GTOC2 set of asteroids..................................................................................118
Figure 51 Set of asteroids for modified GTOC2 problem..............................................120
Figure 52 Optimal impulsive solutions, with and without the time of flight restriction,
for the modified GTOC2 problem. ................................................................123
Figure 53 Results of branch-and-bound algorithm applied to modified GTOC2
problem. .........................................................................................................125
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