"In a paper published in the Journal of Spacecraft and Rockets shortly before Galileo concluded its tour, Andrew Heaton of NASA’s Marshall Space Flight Center and James Longuski of Purdue University demonstrated that the Uranus system could support a complex Galileo-style tour. This was, they acknowledged, “contrary to intuition. . . because the Uranian satellites are much less massive than those of Jupiter.” A Galileo-style tour would be possible, they explained, because “the key to a significant gravity assist is not the absolute size of the satellite, but the ratio of its mass to the primary, and the mass ratios of the Uranian satellites to Uranus are similar to those of the Jovian satellites to Jupiter.” Titania and Oberon form a large outer pair equivalent to Ganymede and Callisto, they noted, while Ariel and Umbriel form a small inner pair equivalent to Io and Europa. The “Uranian satellite system is nearly a smaller replica of the Jovian system,” Heaton and Longuski wrote."
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Image appeared in Issue 18 of magazine "All About Space".