Outer Planet Communication Technologies andRadio Science

Joseph Lazio, Les Deutsch, Stephen Townes

© 2018 California Institute of Technology. Government sponsorship acknowledged.

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The Interplanetary Network View

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Planetary Sciences Vision 2050 3

Exciting and Ambitious!We Have a Challenge …

MRO (max)

Remote Sensing at Other Planets as at Earth

DATARATES

(bits/s)1E+04 1E+05 1E+06 1E+07 1E+08

Data for Science

Direction of IncreasingData Richness

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Cassini(max)

OPAG Technology Forum

Synthetic Aperture Radar, Hyper-Spectral Imagers, High-Resolution Mass Spectrometry, …

Flyby, Orbit, Land, Rove, …

Required Improvement

✔ ✔/2 ✔

History of Downlink Difficulty

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1st flyby of Mars

1st gravity assist to visit multiple

planets: Mercury and Venus

1st close-up study of outer

planets

Jupiter orbiter

Ka-B

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Saturn orbiter

Ka-b

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TV relayed by satellite

1st Mini Computer

1st Cell Phone

IBM PC Released

Internet made Public

1st Hand-Held GPS Receiver

iPhone Released

Discovery of 1,000th planet

1st US Spacecraft to fly

by the Moon

History to date:Performance has improved by 1013 so far

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Ice Giant Mission Concepts

OPAG Technology ForumPre-decisional - For planning and discussion purposes only. 6

Neptune Orbiter with Probe, SEP,

and 50 kg payload

Uranus Orbiter with Probe and 50 kg

payloadCassini with Huygens Probe

Ice Giant Mission ConceptsWhy Do I Care?

OPAG Technology ForumPre-decisional - For planning and discussion purposes only. 7

Neptune Orbiter with Probe, SEP,

and 50 kg payload

Uranus Orbiter with Probe and 50 kg

payload

• More capable instrumentsHigher spectral resolution spectrometers, higher spectral resolution mass spectrometers, higher angular resolution imager

30 km spatial resolution on a moon vs. 100 km spatial resolution

• More capable missionsStereo vision on a moon via multiple looks

Decade 0.5+: 10× Improvement over Today

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• Remove bottlenecks on spacecraft and DSN

– Universal Space Transponder (UST)

– Common Platform DSN signal processor

• Increase use of Ka band (32 GHz)over X band (8 GHz)

– Factor ~ 4× improvementcf. Cassini, Juno Radio Science

Decade 0.5+: 10× Improvement over Today

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+

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+ +• Antenna arraying– DSN Aperture Enhancement Project

emplacing additional 34m antennas

– Provides backup for 70 m as well as arraying beyond 70 m

DSS-56 foundationMadrid

DSN Aperture Enhancement Project (through 2025)Deep Space Network

10Canberra Goldstone Madrid

+ backend digital signal processing

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International Deep Space Network

New NorciaCebrerosMalargüe

CanberraGoldstone

Madrid

UsudaUchinoura Byalalu

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Indicates flow of water before the mountain formedStrata at Base of Mt Sharp

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The DSN and the Interplanetary Internet

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Extends today’s Internet across the Solar System

Mars

Titan

Icy Moon

Moon

z

High Performance Optical Terminal

To be demonstrated on Pysche

Hybrid RF/Optical Antenna

Potential reuse of existing infrastructure, in development today

Dedicated 12m Stations

NASA + International partnerships

Decade 2+: 100× Improvement over TodayDedicated Comm Relays

Extend the Internet to Mars and enable public engagement

14OPAG Technology ForumPre-decisional - For planning and discussion purposes only.

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Laser Communication

Deep Space Optical Communications (DSOC) to be demonstrated!

OPAG Technology ForumPre-decisional - For planning and discussion purposes only.

DSOC Overview

Photon-Counting Camera

Isolation Pointing Assembly

Point-Ahead Mirror

Single strut photoflight-like electronics

FLIGHT LASER TRANSCEIVER (FLT)

Electron microscope detail of 320 µm active area tungsten silicide (WSi) superconducting nanowire single photon

detector (SNSPD) array

Laser Transmitter Average Power 4 W

Packaged Nanowire Array

GROUND TECHNOLOGYAluminum Optical Transceiver

Assembly

SiC Flight Laser Transceiver (FLT)

DSOC Technologies & Advances

Palomar Observatory/Hale Telescope 5 m

z

High Performance Optical Terminal

To be demonstrated on Pysche

Hybrid RF/Optical Antenna

Potential reuse of existing infrastructure, in development today

Dedicated 12m Stations

NASA + International partnerships

Decade 2+: 100× Improvement over TodayDedicated Comm Relays

Extend the Internet to Mars and enable public engagement

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… In the Inner Solar System

OPAG Technology ForumPre-decisional - For planning and discussion purposes only.

OPAG Technology ForumPre-decisional - For planning and discussion purposes only. 18

… In the Outer Solar SystemDecade 2+: 100× Improvement over Today

Increased Data Volume

Laser Communication

??SMAP 6 m antenna (NG

Astro.)

• Diameter (6 m?)• Mass• Surface accuracy• Pointing and stability• …?

Radio Frequency Communication

• Diameter (50 cm?)• Pointing• Laser power?• Spacecraft isolation• …?

Radio ScienceApparent even with early missions that occultations by planetary atmospheres would affect radio communications• Mio dio! Tragedy!• Or one person’s annoyance is

another’s data --- Study atmospheric properties!

“Occultation Experiment: Results of the First Direct Measurement of Mars's Atmosphere and Ionosphere” (Kliore et al. 1965, Science)

• Can also study planetary interior! Turn the DSN+spacecraft

into one giant science instrument

Radio Science in the Outer Solar System

OPAG Technology ForumPre-decisional - For planning and discussion purposes only.

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Future Radio Science

Technologies• Simultaneous dual

frequency links (Cassini, Juno use X- and Ka bands)to difference the Doppler and cancel dispersive noise effects

• Water vapor radiometer to calibrate Earth’s tropospheric noise contribution

“We have identified 12 priority science objectives for ice giant exploration. […] The two most important objectives relate to the formation, structure, and evolution of ice giants (…): • Constrain the structure and

characteristics of the planet’s interior, including layering, locations of convective and stable regions, and internal dynamics.

• Determine the planet’s bulk composition ….Ice Giants Pre-Decadal Study Final Report

Interiors of Moons: Earth’s MoonRadio Science

GRAIL mission made precise measurements of separation between two spacecraft orbiting the Moon• Changes in separation due to acceleration of one

of the spacecraft

• Changes in acceleration result from changes in mass along spacecraft trajectory

• Could also use small spacecraft to study planetary atmospheres

Role for small spacecraft in outer solar system?

OPAG Technology Forum 22

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Conclusions

Ambitious science missions realized iffsufficient data returnedCommunication technologies improvements possible over next decadesRadio Science making and will continue to make valuable contributions

DSN Now

The DSN as a Science Instrument 24http://eyes.nasa.gov/dsn/dsn.html