Simply put, resistance to the creation of a space frontier originates with the insecurities of Western leaders. First, it is clear that everything changes with the emergence of a frontier. Established power structures are usually shaken, not reinforced. (If this is not clear, try reading Walter Prescott Webb's The Great Frontier, particularly the last chapter, and Divided We Stand: The Crisis of a Frontierless Democracy, by the same author.)
Ganymede is larger than Mercury, which is the innermost--and smallest--major planet in our Solar System. The surface area of Ganymede is more than half that of the land area of Earth, and it provides scientists with a wealth of data concerning a great variety of surface features.
Astronomers are still debating Titan's origin. However, its intriguing atmosphere does provide a hint. Several instruments aboard the Huygens spacecraft measured the isotopes nitrogen-14 and nitrogen-15 in Titan's atmosphere. The instruments revealed that Titan's nitrogen isotope ratio most closely resembles that seen in comets that exist in the remote Oort Cloud--which is a sphere composed of hundreds of billions of icy comet nuclei that circle our Star at the amazing distance of between 5,000 and 100,000 AU. This shell of icy objects extends half way to the nearest star beyond our own Sun.