About IVRP

Traditional VRP operates on road networks with static arc costs. The interplanetary equivalent must account for the fact that the cost of traveling between two planets depends entirely on when you depart — driven by the relative positions of the planets and the available launch windows. A transfer that costs 5 km/s Δv at one departure date can cost several times that a few months later.

This temporal, physics-constrained cost function is what separates IVRP from a re-labeled graph problem. It also makes it computationally harder — the search space is the Cartesian product of route assignments and continuous departure dates.