Voyager mission observations

When Thomas Jefferson sent Lewis and Clark into the West, he patterned their mission on the methods of Enlightenment science to observe, collect, document, and classify. Such strategies were already in place for the epic voyages made by explorers like Cook and Van-(5) couver. Like their contemporaries, Lewis and Clark were more than representatives of European rationalism. They also represented a rising American empire, one built on aggressive territorial expansion and commercial gain. 

Supermolecular absorption determines significant features of the atmospheres of the planets and their large moons, such as the vertical temperature profile and the high-altitude haze distribution, and offers opportunities for the determination of abundance ratios of helium and hydrogen, ortho- and para-H2, etc. [390, 396]. In certain spectral bands the spectra may sometimes be obtained by Earth-based observations. More commonly, the spectra will be obtained in space missions, such as IRIS of Voyager I and II future missions (Infrared Space Observatory) will doubtlessly enhance the available information significantly. 

This survey of the current state of knowledge of satellite geochemistry also uncovers the many areas where there are unsolved problems and major issues still to be addressed by future observations and theoretical work. On the observational side, most of the chemical information we now have for objects beyond the Galilean satellites comes from bulk density and global telescopic spectral data. The Cassini/Huygens mission, which arrives at Saturn in July of 2004, will allow more detailed study of all the satellites of this major system. In particular. Titan is now known primarily through detailed study of its upper atmosphere from Voyager and Earth-based... 

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