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

• Mars Astrobiology Explorer-Cacher (MAX-C) —This mission is the first of the three
components of a Mars sample return campaign. It is responsible for characterizing a landing site that has
been selected for high science potential, and for collecting, documenting, and packaging samples for
return to Earth.
• Uranus Orbiter and Probe—This mission deploys a small atmospheric probe into Uranus to
make in situ measurements of noble gas abundances and isotopic ratios, then enters orbit, making remote
sensing measurements of the planet’s atmosphere, interior, magnetic field, and rings, as well as multiple
flybys of the larger uranian satellites.
• Venus Climate Mission—This mission is designed to address science objectives concerning
the Venus atmosphere, including carbon dioxide greenhouse effects, dynamics and variability,
surface/atmosphere exchange, and origin. The mission architecture includes a carrier spacecraft, a
gondola/balloon system, a mini-probe, and two drop sondes.
The cost appraisal and technical evaluations performed for these five candidate Flagship missions
have yielded estimates for the full life-cycle cost of each mission, including the cost of the launch vehicle,
in FY2015 dollars. For missions with international components (EJSM and MAX-C) only the NASA
costs are included. The cost estimates are as follows:
• Enceladus Orbiter, $1.9 billion;
• Jupiter Europa Orbiter, $4.7 billion;
• Mars Astrobiology Explorer-Cacher, $3.5 billion 2 ;
• Uranus Orbiter and Probe, $2.7 billion 3 ; and
• Venus Climate Mission, $2.4 billion.
The committee devoted considerable attention to the relative priorities of the various large-class
mission candidates. In particular, both JEO and the Mars Sample Return campaign (beginning with
MAX-C) were found to have exceptional science merit. Because it was difficult to discriminate between
the Mars Sample Return campaign and JEO on the basis of their anticipated science return per dollar
alone, other factors came into play. Foremost among these was the need to maintain programmatic
balance by assuring that no one mission takes up too large a fraction of the planetary budget at any given
time.
The highest priority Flagship mission for the decade 2013-2022 is MAX-C, which will begin
the NASA-ESA Mars Sample Return campaign. However, the cost of MAX-C must be constrained
in order to maintain programmatic balance.
The Mars community, in their inputs to the decadal survey, was emphatic in their view that a
sample return mission is the logical next step in Mars exploration. Mars science has reached a level of
sophistication that fundamental advances in addressing the important questions above will only come
from analysis of returned samples. MAX-C will also explore a new site and significantly advance our
understanding of the geologic history and evolution of Mars, even before the cached samples are returned
to Earth.
Unfortunately, at an independently estimated cost of $3.5 billion, MAX-C would take up a
disproportionate near-term share of the overall budget for NASA’s Planetary Science Division. This very
high cost results in large part from two large and capable rovers—both a NASA sample-caching rover and
the ESA’s ExoMars rover—being jointly delivered by a single entry, descent, and landing (EDL) system
that is derived from the Mars Science Laboratory (MSL) EDL system. The CATE results for MAX-C
projected that accommodation of two such large rovers would require major redesign of the MSL EDL
system, with substantial associated cost growth.
The committee recommends that NASA should fly the MAX-C mission in the decade 2013-
2022 only if it can be conducted for a cost to NASA of no more than approximately $2.5 billion
(FY2015 dollars). If a cost of no more than about $2.5 billion FY2015 cannot be verified, the mission
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