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

Hubble Space Telescope
Hubble observations are crucial for research on the giant planets (especially Uranus and
Neptune) and their satellites, and for planning future missions to these systems. Hubble’s ultraviolet
capability has been critical for studies of auroral activity on the gas giants, discovery of the
atmospheres of Ganymede and Europa, and investigations of the plumes and atmosphere of Io.
During the past decade, Hubble was also used to discover two additional moons (Nix and Hydra)
around Pluto, and two additional moons (Cupid and Mab) and two new rings around Uranus. Hubble,
although recently serviced, has a finite lifetime and will eventually be de-orbited, and no replacement
space telescope with equivalent ultraviolet capability is currently planned.
James Webb Space Telescope
The James Webb Space Telescope (JWST) will be a 6.5-meter infrared-optimized telescope
placed at Earth’s L2 Lagrange point. It is currently scheduled for launch in 2014. JWST will provide
unprecedented sensitivity and stability for near- and mid-infrared imaging and spectroscopy,
especially at wavelengths blocked by Earth’s atmosphere. JWST will contribute to planetary science
in numerous ways, including diffraction-limited imaging (in the near infrared) of both large and small
bodies difficult to match with existing ground-based facilities, spectroscopy of the deep atmospheres
of Uranus and Neptune, planetary auroral studies with high spatial resolution, and observations of
transient phenomena (storms and impact-generated events) in the atmospheres of the giant planets.
JWST will overlap with several planetary missions, offering unique complementary and
supplementary observations, and can extend studies of Titan beyond the 2017 end of the Cassini
mission. The ability to track moving targets—a necessity for planetary observations—is currently
being implemented. JWST’s Science Working Group is planning many types of solar system
observations, including imaging and spectra of Kuiper Belt objects and comets, as well as Uranus and
Neptune and their satellites and ring systems. Work is currently being done to assess the feasibility of
observations of the brighter planets such as Mars, Jupiter, and Saturn.
Near Earth Object Surveys
The discovery, characterization, and hazard mitigation of NEOs called for in the 2005 NASA
Authorization Act are treated in a recent NRC study 13 and are beyond the scope of this decadal
survey. This section focuses on instrumentation and infrastructure needed for scientific surveys of
NEOs.
Earth-based telescopic observations probe the shapes, sizes, mineral compositions, orbital and
rotational attributes, and physical properties of NEOs. These data are used in defining the science
goals and operational constraints for spacecraft missions to specific asteroids, and are critical for
extrapolating what is learned from the very limited number of asteroid missions that will be possible
to broader populations of small bodies. The Arecibo Observatory and the Goldstone facility are
critical to refining NEO orbital and physical characteristics. New optical facilities, such as the Large
Synoptic Survey Telescope (LSST) and Panoramic Survey Telescope and Rapid-Response System
(Pan-STARRS), can dramatically increase scientific understanding of NEOs by expanding the catalog
of known objects and their orbits, thus providing better population statistics and improved predictions
for close passages by Earth.
Perhaps the greatest advance in characterizing NEOs will come from spacecraft missions that
analyze them from orbit and/or return samples to Earth where sophisticated laboratory techniques can
be brought to bear. The committee conducted a technology study of the accessibility of NEOs using
solar electric propulsion (Chapter 4). With sufficient technology development such missions might
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