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

• Venus In Situ Explorer
• South Pole-Aitken Basin Sample Returm
Venus In Situ Explorer
VISE’s importance was reaffirmed in the NRC’s Opening New Frontiers in Solar System
Exploration. 22 The rationale for VISE is that many crucial analyses of Venus cannot be obtained from
orbit and instead require in situ investigations. Sample return appears beyond current technology, and
Venus’s thick atmosphere limits the primary tools for surface investigations from orbit to radar, radio
science, gravity, and a few windows in near-infrared wavelengths. The science mission objectives for
VISE from these previous reports are as follows:
• Understand the physics and chemistry of Venus’s atmosphere, especially the abundances of
its trace gases, sulfur, light stable isotopes, and noble gas isotopes;
• Constrain the coupling of thermochemical, photochemical, and dynamical processes in
Venus’s atmosphere and between the surface and atmosphere to understand radiative balance, climate,
dynamics, and chemical cycles;
• Understand the physics and chemistry of Venus’s crust;
• Understand the properties of Venus’s atmosphere down to the surface and improve our
understanding of Venus’s zonal cloud-level winds;
• Understand the weathering environment of the crust of Venus in the context of the dynamics
of the atmosphere and the composition and texture of its surface materials; and
• Look for planetary scale evidence of past hydrological cycles, oceans, and life and for
constraints on the evolution of the atmosphere of Venus.
Achieving all of these objectives represents a flagship-class investment, 23 but achieving a
majority is considered feasible in the New Frontiers Program. 24
In the 2003 decadal survey, the long-term goal was extraction and return to Earth of samples
(solid and gas) from the Venus surface, clearly a flagship-class mission, and VISE was considered in
terms of its contribution to this sample return. The 2008 NRC report suggested that VISE not be tied to
Venus sample return, given the huge (and so-far unanswered) technical challenges posed by the latter.
VISE-like missions do, however, provide the rare opportunities for technical demonstrations in the Venus
near-surface environment, and inclusion of demonstration technologies on a VISE mission would be
justified (on a non-interference, non-critical-path basis).
South Pole–Aiken Basin Sample Return
The exploration and sample return from the Moon’s South Pole-Aitken (SPA) basin is among the
highest priority activities for solar system science. The mission’s high priority stems from its role in
addressing multiple science objectives outlined in this report, including understanding the interior of the
Moon and impact history of the solar system. Though recent remote-sensing missions provide much
valuable new data from orbit about the diversity of materials and the geophysical context of this important
basin, achieving the highest-priority science objectives requires precision of age measurements to better
than ±20 million years and accuracy of trace elemental compositions to the parts-per-billion level, which
is only achievable via sample return. The principal scientific reasons for undertaking a South Pole-Aitken
Basin Sample Return mission are as follows:
• Determine the chronology of basin-forming impacts and constrain the period of late heavy
bombardment in the inner solar system, and thus address fundamental questions of inner solar system
impact processes and chronology;
PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION
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