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

Availability of Plutonium-238
Radioisotope power systems are necessary for powering spacecraft at large distances from the
Sun, in the extreme radiation environment of the inner Galilean satellites, in the low light levels of high
martian latitudes, dust storms, and night, for extended operations on the surface of Venus, and during the
long lunar night. With some 50 years of technology development and use of 46 such systems on 26
previous and currently flying spacecraft, the technology, safe handling, and utility of these units are not in
doubt. Of more than 3,000 nuclides, plutonium-238 stands out as the safest and easiest to procure isotope
for use on robotic spacecraft.
This report’s recommended missions cannot be carried out without new plutonium-238
production or completed deliveries from Russia. There are no technical alternatives to plutonium-238,
and the longer the restart of production is delayed, the more it will cost.
The committee is alarmed at the status of plutonium-238 availability for planetary
exploration. Without a restart of plutonium-238 production, it will be impossible for the United
States, or any other country, to conduct certain important types of planetary missions after this
decade.
Research and Analysis Programs
Supporting Research
The research related to planetary missions begins well before a mission is formulated and funded,
and continues long after it is over. Research provides both the foundation for interpreting data collected
by spacecraft, and the guidance and context for identifying new scientifically compelling missions.
Ground-based observations can identify new targets for future missions, and experimental and theoretical
results can pose new questions for these missions to answer. Research and analysis programs also allow
the maximum possible science return to be harvested from missions. And along with analysis of
spacecraft data, the portfolios of research and analysis programs include laboratory experiments,
theoretical studies, fieldwork using Earth analogs, planetary geologic mapping, and analysis of data from
Earth-based telescopes. All of these fields are crucially important to NASA’s long-term science goals, and
all require funding.
Current NASA research and analysis funding in most programs supporting planetary research is
distributed as multiple small grants. An unfortunate and very inefficient aspect of this policy is that
researchers must devote an increasingly large fraction of their time to writing proposals instead of doing
science. The committee strongly encourages NASA to find ways (e.g., by merging related research
programs and lengthening award periods) to increase average grant sizes and reduce the number of
proposals that must be written, submitted, and reviewed by the community.
The number of good ideas for planetary research surpasses the funding available to enable that
research. More funding for research and analysis would result in more high-quality science being done.
However, recommendations for increased research funding must be tempered by the realization that
NASA’s resources are finite, and that such increases will inevitably cut into funds that are needed to
develop new technologies and fly new missions. So an appropriate balance must be sought. After
consideration of this balance, and consistent with the mission recommendations and costs presented
above, the committee recommends that NASA increase the research and analysis budget for
planetary science by 5 percent above the total finally approved FY2011 expenditures in the first
year of the coming decade, and increase the budget by 1.5 percent above the inflation level for each
successive year of the decade.
PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION
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