Vision and Voyages for Planetary Science in the - Solar System ...

ADVANCING STUDIES OF THE SATELLITES OF THE GIANT PLANETS: 2013-2022
The committee considered a wide range of potential mission destinations and architectures,
guided by community input via white papers, with particular emphasis on the recommendations of the
Outer Planet Assessment Group (OPAG). 59 The committee evaluated their cost-effectiveness in
addressing the goals and objectives discussed earlier. The feasibility of several missions studied was
influenced by the availability of gravity assists from Jupiter or Saturn, and the necessary planetary
alignments should be considered when developing long-term strategies for solar system exploration
(Figure. 8.10).
The challenges of the physical scale of the outer solar system and resulting long flight times, and
the relative immaturity of our understanding of outer planet satellites, are best met with the economies of
mission scale: large missions are the most cost-effective. Cassini has spectacularly demonstrated the
value of large, well-instrumented missions, for instance in its multi-instrument discovery and detailed
characterization of activity on Enceladus. There remains a role for smaller missions, however, and
mission studies conducted for the committee demonstrated that scientifically exciting and worthwhile
missions can be conducted for less than the cost of the flagship missions.
FIGURE 8.10 Approximate launch windows for gravity assist trajectories to the outer planets and their
moons. Note the paucity of opportunities between 2020 and 2030, the likely range of launch dates for
missions that have new starts in the coming decade. Arrival dates are much more dependent on the
details of mission design, and are thus not shown here.
PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION
8-27