Multiobjective Mission Planning for Multiple Geosynchronous Spacecraft Refueling

Algorithm 2

The main steps of MOHPSO.

1) Initialization.

 a. Initialize the population POP.

 b. Initialize the memory of each particle, .

 c. Evaluate each of the particles in POP.

 d. Store the non-dominated solutions in the repository Rep.

2) WHILE maximum number of cycles has not been reached, do

 a. Update particles using crossover and mutation:

  ;

  ;

  ;

  where is a value that is taken from the repository Rep and the selection method could be

  found in [27]. In each case, if the new particle is better than the old one, then it will

  be accepted.

 b. Update the particles in Rep: Insert all the currently non-dominated particles into Rep and eliminate

  the dominated particles from Rep. When the repository gets full, we apply a secondary criterion for

  retention: those located in less populated areas of objective space are given priority over those lying

  in highly populated regions.

 c. Update the memory of each particle: if the current particle is better than the one contained in its

  memory, it is updated using: .

 d. Increment the loop counter.

3) END WHILE.

4) RETURN Rep.