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

adar telescopes for planetary studies. Ground-based facilities that receive NASA support, including
the Infrared Telescope Facility, the Keck Observatory, Goldstone, Arecibo, and the Very Long
Baseline Array, all make important and in some cases unique contributions to planetary science.
NASA should continue to provide support for the planetary observations that take place at these
facilities.
Balloon- and rocket-borne telescopes offer a cost-effective means of studying planetary bodies at
wavelengths inaccessible from the ground. Because of their modest costs and development times, they
also provide training opportunities for would-be developers of future spacecraft instruments. Although
NASA’s Science Mission Directorate regularly flies balloon missions into the stratosphere, there are few
funding opportunities to take advantage of this resource for planetary science, because typical planetary
grants are too small to support these missions. A funding line to promote further use of these
suborbital observing platforms for planetary observations would complement and reduce the load
on the already over-subscribed planetary astronomy program.
The Deep Space Network
The DSN is a critical element of NASA’s solar system exploration program. It is the only asset
available for communications with missions to the outer solar system, and is heavily subscribed by inner
solar system missions as well. As instruments advance and larger data streams are expected over the
coming decade, this capability must keep pace with the needs of the mission portfolio. Future demands on
the DSN will be substantial. Missions to the distant outer solar system requires access to either 70-meter
antennas or equivalent arrays of smaller antennae. The DSN must also be able to receive data from more
than one mission at one station simultaneously. If arrays can only mimic the ability of one 70-meter
station and nothing more, missions would still be downlink constrained and would have to compete
against one another for limited downlink resources.
Although Ka-band downlink has a clear capacity advantage, there is a need to maintain multiple
band downlink capability. For example, three-band telemetry during outer planet atmospheric
occultations allows sounding of different pressure depths within the atmosphere. In addition, S-band is
required for communications from Venus during probe, balloon, lander, and orbit insertion operations
where other bands cannot penetrate the atmosphere. X-band capability is required for communication
through the atmosphere of Titan, and also for emergency spacecraft communications. The committee
recommends that all three DSN complexes should maintain high power uplink capability in X and
Ka-band, and downlink capability in S, Ka, and X-bands. NASA should expand DSN capacities to
meet the navigation and communication requirements of missions recommended by this decadal
survey, with adequate margins.
Sample Curation and Laboratory Facilities
Planetary samples are arguably some of the most precious materials on Earth. Just as data
returned from planetary spacecraft must be carefully archived and distributed to investigators, samples
brought to Earth from space at great cost must be curated and kept uncontaminated and safe for continued
study.
Samples to be returned to Earth from many planetary bodies (e.g., the Moon, asteroids, and
comets) are given a planetary protection designation of “Unrestricted Earth Return” as they are not
regarded as posing any biohazard to Earth. However, future sample-return missions from Mars and other
targets that might potentially harbor life (e.g. Europa and Enceladus) are classified as “Restricted Earth
Return” and are subject to quarantine restrictions, requiring special receiving and curation facilities. As
plans move forward for Restricted Earth Return missions, including Mars sample return, NASA should
establish a single advisory group to provide input on all aspects of collection, containment,
characterization and hazard assessment, and allocation of such samples.
PREPUBLICATION COPY—SUBJECT TO FURTHER EDITORIAL CORRECTION
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