Abstract
The Galileo spacecraft exploration has shown a probability that Europa has a large amount of water under its icy surface, as well as that some kinds of life may be present on Europa. In the present study, feasibility analysis for Japan’s Europa exploration is carried out in terms of interplanetary and Jupiter atmospheric flight trajectories. First, three types of interplanetary trajectories from the Earth to Jupiter, i.e. direct, Mars gravity-assisted, and Venus-Earth gravity-assisted, are calculated and the case of the minimum Jovian insertion energy, i.e. the maximum deliverable mass, is selected in each type of the trajectories. Second, flight trajectories in the Jovian atmosphere for decelerating and deploying spacecraft to Europa are calculated and the required mass of the ablator is evaluated. It is clearly shown that aerobraking is much more advantageous for enhancement of deliverable mass than applying chemical propulsion alone, and that the combination of H-IIA Augmented Launch Vehicle, gravity assists, and aerobraking will enable Europa biological explorations.
