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

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. Finally, the DSN is crucial for precision spacecraft ranging and navigation, and this
capability must be maintained.
TABLE 10.2 Typical Data Volumes (Gbit transmitted in an 8-hour pass) for Some Current and
Future Planetary Missions Using Different DSN Antennas and Communication Bands
Antenna Band
Typical data volume, Gbit/8-hour pass
Max Data Rate
(kbps) a MRO b JEO c Cassini d Uranus e
34-m X 8,400-8,500 115
New
Horizons f
at Pluto
1 0.001
Ka 31,800-32,300 86 g 4 0.2
70-m X 8,400-8,500 173 4 0.003
or array Ka 31,800-32,300 800 h 18 0.9
a Actual downlink rate depends on spacecraft transmitter power, High Gain Antenna size/gain, distance, DSN
elevation, weather.
b
MRO has 35W Ka and 100W X-band transmitters, 3-m High Gain Antenna, 160-Gb storage.
c
JEO assumes 25W X and Ka-band transmitters, 3-m High Gain Antenna, 17-Gb storage.
d
Cassini has 20W X-band transmitter, 3-m High Gain Antenna, 4-Gb storage.
e
Uranus Orbiter and Probe assumes 40W Ka-band transmitters, 2.5-m High Gain Antenna, 32-Gbit Storage.
f
New Horizons has 12W X-band transmitter, 2.1-m High Gain Antenna, 132-Gb storage.
g
Non-optimal test case.
h
Best case.
NOTE: Bold text denotes downlink-limited cases, and italic text denotes theoretical capability.
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 are a “gift that keeps on giving”, yielding discoveries long after they
have been collected and returned. Even today, scientists are using new, state-of-the-art laboratory
instruments to discover new things about lunar samples collected during the Apollo program four
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