Employing multiple gravity-assist flybys of Jupiter's Galilean moons can save a substantial amount of ΔV when capturing into orbit about Jupiter. (Saving ΔV means that less of the spacecraft's propellant mass would be needed to capture into Jupiter orbit.) An example double-satellite-aided capture sequence is depicted in Figure 1. A spacecraft arrives at the Jupiter system from an interplanetary trajectory from Earth, performs gravity assists of Jupiter's moons Callisto and Ganymede, and completes the capture with a Jupiter orbit insertion (JOI) maneuver at perijove (its closest approach distance to Jupiter).