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

• Long-lived, flight qualified ASRGs, with lifetimes in excess of 15 years;
• Lightweight materials for the orbiter structure and subsystems; and
• Thermal protection systems for the probe.
Although the Uranus mission can be accomplished using chemical propulsion, the availability of
a flight-tested, comparatively inexpensive solar-electric propulsion module would result in both a wider
range of launch dates and more mass in orbit around Uranus. Aerocapture capability would enhance a
Uranus orbiter mission. For a Neptune orbiter, the advantages of aerocapture are enormous.
Enceladus Orbiter
The Enceladus Orbiter’s key scientific instruments are a mass spectrometer, a thermal mapping
radiometer, a dust analyzer, an imaging camera, and a magnetometer. Other than improvements in the
sensitivity and accuracy of the mass spectrometer and thermal mapping radiometer in particular, which
would enhance the scientific mission, the major technological challenge is ensuring reliability and
lifetime of the ASRGs. The mission requires three ASRGs to deliver power throughout the Enceladus
orbit phase, which lasts for at least a year beginning 12 years after launch. Because of the potential
habitability of Enceladus, planetary protection is an additional technological challenge for an orbiter
mission.
Venus Climate Mission
The Venus Climate Mission (VCM) includes four distinct flight elements: the carrier spacecraft
that becomes a Venus orbiter, a gondola/balloon system, a mini-probe, and drop sondes. The packaging
of the mini-probe and the drop sondes, especially integration of a sophisticated neutral mass spectrometer
in the mini-probe, is the key technological challenge of VCM. Although each of the components of the
entry flight system, which contains the gondola and the balloon, is close to TRL 6, indicating
technological maturity, the entry flight system itself is still a significant design and development
challenge. The management of the power, mass, and volume of this “Russian doll” vehicle throughout its
design cycle could be viewed as a technology development in its own right.
Future Mission Capabilities: 2023-2032
During the coming decade, the missions recommended by this decadal survey will address the
most compelling science objectives within the limited resources available to NASA. It is essential that
the Planetary Science Division also invest in the technological capabilities that will enable missions in the
following decade. During the course of this decadal survey, a number of mission concepts have been
studied to assess their cost, feasibility, and scientific value, and these studies provide the foundation for
important technology investments. Table 11.1 summarizes these missions and their key technology
drivers. The committee strongly recommends that NASA strive to achieve balance in its technology
investment programs by addressing both the near-term missions cited specifically in this report, as
well as the longer-term missions that will be studied and prioritized in the future.
PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION
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