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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the sample problem reduces the number of asteroid sequences from 3072 to 512. This<br />
eliminates only two asteroid sequences with feasible solutions, both <strong>for</strong> the following<br />
order: Earth – Group 4 – Group 1 – Group 2/3. The maximum final mass <strong>for</strong> each of<br />
these two sequences, however, is only 608 kg <strong>and</strong> 524 kg, which ranks these solutions<br />
59 th <strong>and</strong> 105 th out of the now 117 feasible asteroid sequences.<br />
The next metric considered is the change in inclination between the orbits of two<br />
asteroids. Figure 20 plots the maximum final mass <strong>for</strong> each leg-by-leg asteroid pair, over<br />
the date range considered, as a function of the absolute value of the inclination change<br />
between the starting <strong>and</strong> ending body (no differences were found in the results if a<br />
distinction was made between positive <strong>and</strong> negative inclination changes). As will be true<br />
<strong>for</strong> all similar plots presented, only asteroid pairs that were actually analyzed are plotted.<br />
For example, four of the eight Group 4 asteroids yielded no feasible Leg 1 trajectories,<br />
<strong>and</strong> were there<strong>for</strong>e not considered in analyzing subsequent Leg 2 <strong>and</strong> Leg 3 trajectories.<br />
For Leg 1, because there were only eight possible pairs, additional Group 4 asteroids<br />
were r<strong>and</strong>omly selected <strong>and</strong> analyzed in order to add more data points. Furthermore, any<br />
asteroid sequences that resulted in a maximum final mass of less than 500 kg were<br />
deemed infeasible <strong>and</strong> appear as 0 kg in the plots.<br />
Maximum Final Mass (kg)<br />
1500<br />
Leg 1<br />
1250<br />
Leg 1 (added)<br />
1000<br />
750<br />
500<br />
250<br />
0<br />
0.00 20.00 40.00 60.00<br />
Inclination Change (deg)<br />
Maximum Final Mass (kg)<br />
1200<br />
Leg 2<br />
1000<br />
800<br />
600<br />
400<br />
200<br />
0<br />
0.00 20.00 40.00 60.00<br />
Inclination Change (deg)<br />
Maximum Final Mass (kg)<br />
1000<br />
900<br />
Leg 3<br />
800<br />
700<br />
600<br />
500<br />
400<br />
300<br />
200<br />
100<br />
0<br />
0 10 20 30 40<br />
Inclination Change (deg)<br />
Figure 20: Maximum final mass <strong>for</strong> each asteroid sequence as a function of inclination change.<br />
For Leg 1 <strong>and</strong> Leg 2, there is a perceptible correlation between final mass <strong>and</strong><br />
inclination change, where smaller values of inclination change result in larger values of<br />
59