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Home , ASTER (spacecraft), NASA Deep Space Network, Space Network

Lecture 10.1: NASA’s Deep : Current Status and the Future

В. Г. Турышев Jet Propulsion Laboratory, Institute of Technology 4800 Oak Grove Drive, Pasadena, CA 91009 USA Государственный Астрономический Институт им. П.К. Штернберга Университетский проспект, дом 13, Москва, 119991 Россия

Курс Лекций: «Современные Проблемы Астрономии» для студентов Государственного Астрономического Института им. П.К. Штернберга 7 февраля –23мая 2011 FUTURE OF DEEP SPACE NAVIGATION Outline

• General consideration • Strategy of DSN evolution – List of current capabilities – Future needs • Principles of Deep Space Communications • Progress 1962-2004 • Mission examples: – Voyager mission to outer planets – to – Cassini to Saturn – Odyssey to Mars • Concluding Remarks Deep Space Network

Goldstone, California Goldstone, California

Madrid,

Canberra, FUTURE OF DEEP SPACE NAVIGATION Future’s NASA Navigation System

Formation In-Situ Flying In-Situ Assets Ascent Assets Vehicles Pinpoint Landing

Complementary, Supplementary Data Types

DSN Array Low-Thrust, Low-Energy Advanced Trajectories Interferometric Autonomous Data Types Small-body Optical Proximity Navigation Operations FUTURE OF DEEP SPACE NAVIGATION Reference Set for Navigation Requirements (2005)

Crew Exploration Vehicle (2008, in 2020, Mars in 2030) Lunar South Pole Sample Return (2010) Human rating of deep space Going back to the Moon after 30 years, navigation capabilities, emphasis on but with more demanding requirements: risk-reduction; complementary and landing in deep craters or at the pole; supplementary navigation methods. autonomous 6-DOF GNC for landing It will evolve to enable the human and ascent. exploration of the Moon and Mars. Jupiter Icy Orbiter (2015?) Low-thrust and low-energy Mars Telecom Orbiter (2009-cancel) navigation inside the Jovian Demonstrating autonomous optical system, requiring innovative navigation for rendezvous; gimbaled trajectory optimization and camera; providing enhanced in-situ automated on-board control. navigation and telecom assets. Titan Aerorover (2025) (2009-11) Autonomous atmospheric The heaviest rover ever flown to Mars; a GNC in an unknown precursor to human missions environment. demonstrating powered, precision landing.

Mars Sample Return (2013) Terrestrial Planet Finder (2018?) Pinpoint landing, ascent GNC, Formation-flying at an Mars-orbit rendezvous and unprecedented level of docking, first trip from Mars to accuracy. . FUTURE OF DEEP SPACE NAVIGATION A Timeline of Capabilities (as seen in 2005)

Mars Mars Mars Telecom Reconnaissance Telecom Orbiter Orbiter Orbiter JIMO

Mars Science Mars Sample Lab Return

Next Next Low-Thrust Generation Autonomous Generation Trajectory Traj. Design Rendezvous Nav S/W Control Tools Ka-Band Mars UHF Autonomous Mars UHF Opti-metric Interferometric 2-way EDL Rendezvous 2-way EDL Ranging Demo Demo Demo Demo Demo

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 FUTURE OF DEEP SPACE NAVIGATION A Timeline of Capabilities (as seen in 2005)

Human Lunar Missions Aerorover

Next Generation MTO Human Mars Planet Missions Finder

In-Situ Opti- Advanced Substantial Nav Network-Based Metric Autonomous Infrastructure at Navigation Ranging On-board Nav Mars

2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 FUTURE OF DEEP SPACE NAVIGATION Performance-Enhancing Capabilities

Key capabilities Enhancing Capabilities that enable ultimate Advanced Advanced performance Ground- Optical Software Re- Autonomous Frequency & In-Situ Based Radio- Systems Engineering Navigation Time Assets Performance Measure Metrics Systems High precision Orbit control accuracy Advanced Gimbaled On-board GNC dynamical and High precision VLBI, range, camera, moon using in-situ Tie to target on approach, Mars & measurement 1-way data Ka-band tracking radio, optical terrestrial bodies models High precision Orbit control accuracy Gimbaled Advanced VLBI, dynamical and On-board GNC High precision camera, moon - on approach, outer range, Ka-band measurement using optical 1-way data tracking planets models High precision High Precision On-board GNC Orbit control accuracy, Landmark dynamical and High precision Tie to planetary Doppler, using in-situ tracking measurement 1-way data reference frame in orbit Ka-band radio, optical models High precision On-board High Precision Orbit reconstruction dynamical and estimation High precision Tie to planetary Doppler, - measurement using in-situ 1-way data reference frame accuracy, in orbit Ka-band models radio, optical High precision On-board GNC Landing accuracy on dynamical and using in-situ Tie to planetary - Descent imager - surface measurement radio, optical, reference frame models IMU, radar, laser On-board High Precision High precision Position determination Landmark estimation High precision Tie to planetary Doppler, measurement tracking using in-situ 1-way data reference frame of landed vehicle range, Ka-band models radio FUTURE OF DEEP SPACE NAVIGATION Navigation Tracking-Metrics Requirements (12/2007)

Tracking Error Source current 2010 2020 2030 units (1σ Accuracy) capability reqt reqt reqt Doppler/random (60s) mm/s 0.03 0.03 0.03 0.02 Doppler/systematic (60s) mm/s 0.001 0.003 0.003 0.002 Range/random m 0.3 0.5 0.3 0.1 Range/systematic m 1.1 2 2 1 Angles deg 0.01 .04 .04 .04 VLBI nrad 2.5 2 1 0.5 Troposphere zenith delay cm 0.8 0.5 0.5 0.3 Ionosphere TECU 5 5 3 2 Earth orientation (real-time) cm 7 5 3 2 Earth orientation (after cm 5 3 2 0.5 update) Station locations cm 3 2 2 1 (geocentric) Quasar coordinates nrad 1 1 1 0.5 Mars ephemeris nrad 2 3 2 1 FUTURE OF DEEP SPACE NAVIGATION Approved Mission Set: DSN Supports*

Legacy LEO HEO, Lunar, L1 & L2 DEEP SPACE*** • RADARSAT (O) • CHANDRA (O) • GALILEO (O) • (F) • WMAP (O) • (O) • NEW FRONTIERS (F) (X) • INTEGRAL (O) • CASSINI (O) • GRAVITY PROBE B • ISTP-GEOTAIL (O) • NOZOMI (O) (O)**** • ISTP-WIND (O) • (O) • EVN (O)**** LEOP** • ISTP-SOHO (O) • (O) • GBRA (O)**** • ISTP-POLAR (O) • GSSR (O)**** • MEGA (O)**** • GOES N-P (C) • ACE (O) • MUSES-C (C), (F per MSD) • SIRTF (C) • NOAA N, N’ (C) • IMAGE (O) • (C) • KEPLER (C) • PROSEDS (C) • IMP-8 (O) • MARS EXPLORATION ROVERS A & B (C) • SIM (F) • SOLAR-B (F) • ISTP-CLUSTER II • (C) • VOYAGERS 1 & 2 (O) (O) • (C) • (O) • (O) • MESSENGER (C) • STEREO A & B (C) • LUNAR-A (F) • MARS RECONNAISSANCE ORBITER (C) • ORBITAL DEBRIS (O) NOTES • ST-5 (C) • (C) • SPACE GEODESY (O) • MARS SCOUT (F) • DISCOVERY (F) (X) *~20 additional spacecraft fall under “Emergency Support Only” and are not shown. • MARS TELESAT (F) • MIDEX (F) (X) • MARS SCIENCE LABORATORY (F) • NMP (F) (X) **LEOP = Launch & Early Operations Phase; almost all DSN missions receive such support, but those listed as “LEOP” receive no other significant DSN support. KEY

***Deep Space includes missions utilizing Earth Structure & Evolution of Theme Sun-Earth Connection Theme leading and trailing orbits, since spacecraft in Astronomical Search for Origins Theme Cross-Theme Affiliation such orbits drift out well beyond Exploration of the Theme distances. Unaffiliated with Space Science Enterprise (O) = Operating (as of 4/03) ****Support assumes the form of ground-based (C) = Commitment to support, but not yet operating (as of 4/03) observations for mission reference ties (e.g., GP- (F) = Future commitment to support anticipated (as of 4/03) B), VLBI co-observations, , solar (X) = Not specifically called out in Code S approved “Mission Set Database” or “Mission Set system radar, or orbital debris. Change Log” FUTURE OF DEEP SPACE NAVIGATION Future Science Missions from the SMD Roadmaps**

• GLAST •LISA • CONSTELLATION-X • BIG BANG OBSERVER • GRAVITY PROBE B • DARK ENERGY PROBE • INFLATION PROBE • BLACK HOLE IMAGER •SWIFT • EXPLORER MISSIONS • BLACK HOLE FINDER • EXPLORER MISSIONS • SPIDR PROBE •EUSO • EXPLORER MISSIONS •WISE SEU • SPACE INFRARED • SPACE INTERFEROMETRY MISSION • TERRESTRIAL PLANET FINDER • SPACE ULTRAVIOLET / TELESCOPE FACILITY • SINGLE APERTURE FAR- OPTICAL TELESCOPE • KEPLER • JAMES WEBB SPACE INFRARED OBSERVATORY • LIFE FINDER TELESCOPE • EXPLORER MISSION • PLANET IMAGER • EXPLORER MISSION • DISCOVERY MISSION • EXPLORER MISSION • DISCOVERY MISSION • DISCOVERY MISSION ASO • DEEP IMPACT • DISCOVERY MISSIONS • DISCOVERY MISSIONS • DISCOVERY MISSIONS • MESSENGER • SOUTH POLE AITKEN BASIN • JUPITER POLAR ORBITER/PROBES* • MARS SCOUTS •DAWN SAMPLE RETURN • VENUS IN-SITU EXPLORER • MARS UPPER ATMOSPHERE ORBITER* • MARS SCOUT • JUPITER ICY MOONS ORBITER* • SURFACE SAMPLE RETURN • MARS SAMPLE RETURN • NEW HORIZONS • MARS SCOUTS • MARS SCOUTS • • MARS EXPLORATION ROVERS • MARS SCIENCE LABORATORY • MARS LONG-LIVED LANDER NETWORK• TITAN EXPLORER ESS** • MARS RECONNAISSANCE ORBITER • ORBITER WITH PROBES*

• SOLAR-TERRESTRIAL RELATIONS •MAGCON • AURORAL MULTISCALE OBSERVATORY • SOLAR PROBE • GEOSPACE SYSTEM RESPONSE IMAGER •THEMIS • TELEMACHUS • INTERSTELLAR PROBE • IONOSPHERE • SOLAR CONNECTIONS OBSERVATORY FOR PLANETARY ENVIRONS • GEOSPACE ELECTRODYNAMIC THERMOSPHERE • SOLAR POLAR IMAGER CONNECTIONS MESOSPHERE WAVES • DAYSIDE BOUNDARY LAYER CONSTELLATION • MAGNETOSPHERIC MULTISCALE COUPLER • MAGNETOSPHERE-IONOSPHERE OBSERVATORY SEC*** • SOLAR DYNAMICS OBSERVATORY • HELIOSPHERIC IMAGER AND • PARTICLE ACCELERATION SOLAR ORBITER • RADIATION BELT STORM PROBES GALACTIC OBSERVER • L1-DIAMOND Key • IONOSPHERE THERMOSPHERE • RECONNECTION AND • MAGNETIC TRANSITION REGION PROBE STORM PROBES MICROSCALE • SOLAR IMAGING RADIO ARRAY • INNER • STELLAR IMAGER DSN Support • CINDI SENTINELS • SUN EARTH ENERGY CONNECTOR Likely •TWINS • SOLAR ORBITER • SUN-HELIOSPHERE-EARTH CONSTELLATION DSN Support •AIM • INNER MAGNETOSPHERIC • NEPTUNE ORBITER* Possible CONSTELLATION • IO ELECTRODYNAMICS • TROPICAL ITM COUPLER • MARS AERONOMY* DSN Support • VENUS AERONOMY Unlikely • JUPITER POLAR ORBITER*

*Indicates possible overlap between ESS and SEC. **ESS based on Planetary Decadal Survey + President’s 20082013 2018 2023 FY04 Budget ; some missions may be New Frontiers missions; some SEU & SEC missions derived from latest Explorer awards. Very Approximate Launch Epoch ***Some missions may be Explorer or Discovery. FUTURE OF DEEP SPACE NAVIGATION 20-Year Horizon: Downlink -- 10.6 AU Titan Orbiter/Relay Scenario (Maximum Supportable Rates with RF Flight Hardware Improvements and Ka Ground Improvements

Direction of Increasing Data Richness X-SAR SIR-C & Cassini SAR Synthetic Aperture Radar SRTM SRTM SAR (X-band) (C-band) AIRSAR

Landsats Data for Science Terra 12-Channel IMP 1,2, &3 MSS ASTER (TIR) Pancam/min Lansats NEMO, OrbView-4, Cassini 4&5 TM EO-1 ALI “Adequate” Landsat 7 VIMS Multi-Spectral & Hyper-Spectral Imagers Terra Science ETM+ OrbView-2 12-Channel Terra ASTER Image/min* AVIRIS IMP Pancam/min ASTER (VNIR) Cassini ISS (4bpp) “Quality” (3:1 compression) (SWIR) Science MGS MOC Image/min* DATA Planetary Images RATES (bits/s) 1E+04 1E+05 1E+06 1E+07 1E+08 “Adequate” Public Ave. MPEG-2 (704x480 Raw NTSC Image/min* MPEG-1 at 30 frames/sec) Studio Quality (1bpp) (352x240 at Video (720x486 30 frames/sec) Video at 30 frames/sec) Data for Public

Anticipated maximum supportable ATV Standard ATV (Min.) Gen. Delivery data rate (circa 2012) for link Standard Rate(6MHz between Titan S/C 10.596 AU from Earth (Max.) HDTV Channel) with 100w TWTA and 5m HGA and DSN: Direction of Increasing IMAX Sense of Presence 34m at Ka-band 6.8E+8 bps with 70m at Ka-band 200:1 compression *Reference picture is 1024 x 1024 with 12 bit depth. Planetary 70m at Ka-band compression characterizations from A. Kiely and F. Pollara. With 1kW TWTA on Nuclear Spacecraft FUTURE OF DEEP SPACE NAVIGATION Level-1 Navigation Requirements

Navigation Capability 2005 2010 2020 2030 Orbit control accuracy on approach, 2km 2km 1km 0.5km Mars & terrestrial bodies MER MSL MSR CEV Orbit control accuracy on approach, 20km 20km 2km 10km outer planets Cassini Cassini JIMO Titan Explorer 5km 5km 1km <1km Orbit control accuracy, in orbit MRO MRO MSR CEV 10m 10m 1m radial <1m Orbit reconstruction accuracy, in orbit Current JPL MGS MGS JIMO CEV Capabilities 21km x 5km 5km x 5km 25m x 25m 100m x 100m Require Planned Landing accuracy on surface Technologies & MER MSL CSSR CEV Implementations 20m 1m 1m 1m Position determination of landed vehicle Require New MER MSL MSR CEV Technologies

 Many of the navigation capabilities required for the new vision are currently available, but some new missions have requirements that cannot be fulfilled without improving existing capabilities or developing new technologies: – Precise and rapid trajectory optimization, determination, prediction and control for approaching, orbiting or landed assets, down to kilometers or even meters. – Pinpoint landing to within a few tens of meters at the Moon and Mars, or meters at a small body. – Low-energy and low-thrust trajectory optimization and control, especially when orbiting the moons of gas giants. – Autonomous GNC, formation flying, small-body proximity operations, and rendezvous and docking in outer space. – Complementary and supplementary navigation assets or methods to avoid single-point failures. – Improvements in attitude knowledge & control required to accurately point narrow beams for optical communications FUTURE OF DEEP SPACE NAVIGATION A Flexible and Capable Navigation System

Missions will choose which capabilities to use and how to use them based on requirements, risk posture, and budget

A human mission to Mars may use redundant means to enhance human safety and reduce mission risk: A lunar rover − Ground-based radio-metric could use just a − Proximity radio for in-situ assets proximity radio − Optical camera and lunar relay − Radar orbiters −IMU

A robotic mission sampling a near- Earth object could use an optical navigation camera and a LIDAR A Hubble repair mission may use radio-metrics and an optical camera for rendezvous and docking FUTURE OF DEEP SPACE NAVIGATION Space Network – 2010 Capabilities FUTURE OF DEEP SPACE NAVIGATION Deep Space Network in 2010

NASA is considering implementing a 12m antenna array designed to grow at least up to 400 antennas. This would provide an aperture equal to a 240m antenna or 120 times the capability of the current 70m X-band antenna. FUTURE OF DEEP SPACE NAVIGATION Purposes of Deep Space Communications

• Tracking – To permit the dialogue between G and S/C initiate • Commands – For the mission guide – To alter the planned profile of the mission – To modify the TLC system itself while technology improves • – Transmission of scientific and engineering data from S/C FUTURE OF DEEP SPACE NAVIGATION Characteristics

• Commands Characteristics: – Low data volume – Requirement of extremely high quality (no misunderstanding of the orders can be tolerated) • Telemetry Characteristics: – Image telemetry • Large volume of data • Requirement of moderate quality – Non-image telemetry • Small volume of data • Requirement of high quality FUTURE OF DEEP SPACE NAVIGATION Up-link Characteristics

• Large transmitter power (up to 10 kW) • Large transmitter antenna (up to 70 m) • Small receiving antenna • Non-sophisticated receiver (to be highly reliable) • Moderate computing power (for data processing)

–Low data volume ( rate = 10 ÷ 100 bit/s ) ‐7 – Requirement of extremely high quality ( error probability Pe = 10 ) FUTURE OF DEEP SPACE NAVIGATION Down-link Characteristics

• Small transmitter power (3 ÷ 30 W) • Small transmitter antenna (1 ÷ 5 m) • large receiving antenna (30 ÷ 70 m) • Ultra-sophisticated receiver (reliability is not a problem) • Ultra-high computing power (for data processing)

•Image telemetry –Low data volume ( rate = 10 ÷ 100 bit/s ) ‐7 – Requirement of extremely high quality ( error probability Pe = 10 ) •Non‐image telemetry –Low data volume ( rate = 10 ÷ 100 bit/s ) ‐7 – Requirement of extremely high quality ( error probability Pe = 10 ) FUTURE OF DEEP SPACE NAVIGATION Principle of telemetry (1)

Optimal Reception (in the absence of coding)

OPTIMUM â s(t) Σ n RECEIVER

n0(t) additive Gaussian noise • Baseband signal format

– binary data sequence – is the pulse shape – is the symbol period

Optimum minimum bit error probability Pe FUTURE OF DEEP SPACE NAVIGATION Principles of telemetry (2) Optimal Reception (in the absence of coding)

The bit error probability

is a decreasing function of

where is the net received power (in watts) is Boltzmann’s constant is the noise temperature (in Kelvin) is the bit rate (in bit/s) FUTURE OF DEEP SPACE NAVIGATION Principles of telemetry (3)

Evaluation of net received power

The net received power is given by FUTURE OF DEEP SPACE NAVIGATION Principles of telemetry (4) Evaluation of net received power:

The net received power is a very small number ! FUTURE OF DEEP SPACE NAVIGATION Principles of telemetry (5)

Bit rate evaluation

To assure a given Pe, a minimum S/N is required

where

with FUTURE OF DEEP SPACE NAVIGATION Principles of telemetry (6) Summary -3 • For a reliable TLC link, e.g. Pe = 10 for image telemetry, an S/N must be assured –foruncoded transmission –forsophisticated coded transmission

• Transmitting antenna Gain

where – is the antenna efficiency – is the antenna area – is the RF carrier frequency FUTURE OF DEEP SPACE NAVIGATION Sky Noise Temperature (1) (in the absence of atmosphere)

where FUTURE OF DEEP SPACE NAVIGATION Sky Noise Temperature (2) FUTURE OF DEEP SPACE NAVIGATION Concluding remarks (1)

The highest TLC performance was reached by at Neptune’s on August 24, 1989 with

Absolutely the most powerful TLC system ever built !!

Potentially Galileo with the full displayed antenna and the DSN of 1995 would have a higher performance with an improvement factor of 2. FUTURE OF DEEP SPACE NAVIGATION Concluding remarks (2)

What does Means 21.6 kbit/s from 30 A.U. ?

• Bit rate from Jupiter (5 A.U.) 21.6 (30/5)2 = 777.6 kbit/s

• Bit rate from Mars at minimum distance (0.38 A.U.) 21.6 (30/0.38)2 = 134.62 Mbit/s • Bit rate from 1 light year (63000 A.U.) 21.6 (30/63000)2 = 4.92 mbit/s = 17.7 bit/h • Bit rate from Earth geostationary orbit (38000 km)

3 Tbit/s

corresponding to 64 millions of TF channels !! FUTURE OF DEEP SPACE NAVIGATION Main NASA missions to planets FUTURE OF DEEP SPACE NAVIGATION Cassini Spacecraft FUTURE OF DEEP SPACE NAVIGATION Beam Elementary Equations (1)

• Planar beam angle

– wavelength – diameter of TX antenna (or telescope) • Antenna gain

• Beam diameter at distance D FUTURE OF DEEP SPACE NAVIGATION Beam Elementary Equations (2) Example (from Jupiter: D = 5 A.U.)

RF (Ka band, 30 GHz)

Optical FUTURE OF DEEP SPACE NAVIGATION Optical Telecomm. from Mars FUTURE OF DEEP SPACE NAVIGATION Future Science and Outreach Needs FUTURE OF DEEP SPACE NAVIGATION Optical Communications Vision and Mission

• Vision: – To increase volume of space data transfer, – to enable affordable virtual presence throughout the solar system. • Mission: – 10-100 times higher data-rate, – 1/100 the aperture area, – less mass and less power consumption – …relative to current state-of-the-art.

Over the next 30 years to enhance the current communications capability (1Mbps for Mars 05) by 30 dB (3 orders of magnitude) FUTURE OF DEEP SPACE NAVIGATION Beam Divergence (Frequency) Effect FUTURE OF DEEP SPACE NAVIGATION Near Earth vs. Deep Space FUTURE OF DEEP SPACE NAVIGATION Illustration of Pointing Requirements (for Mars) FUTURE OF DEEP SPACE NAVIGATION Implementation Concepts FUTURE OF DEEP SPACE NAVIGATION Multi-Telescope Reception FUTURE OF DEEP SPACE NAVIGATION Coding (1)

• Source coding – PCM 5 Mbit / imagine – DPCM (1986) 1.5 Mbit / imagine 1/3 – DCT (1996) 500 kbit / imagine 1/10

• Channel coding –Golay (10 dB above Shannon limit) – Reed Solomon (1986) (3.5 dB above Shannon limit) – Turbo codes (1996) (1.1 dB above Shannon limit) FUTURE OF DEEP SPACE NAVIGATION Coding (2) FUTURE OF DEEP SPACE NAVIGATION Coding (3) FUTURE OF DEEP SPACE NAVIGATION Deep-Space Network Road Map FUTURE OF DEEP SPACE NAVIGATION Ka-band Deep-Space Road Map FUTURE OF DEEP SPACE NAVIGATION Optical Deep-Space Road Map FUTURE OF DEEP SPACE NAVIGATION Network Capacity Road Map Near Future Capabilities for Deep Space Navigation FUTURE OF DEEP SPACE NAVIGATION Typical Data Types for Spacecraft Navigation

Current Data Type Characteristics Typical Mission Phases Accuracy

All. Only data type used for Mars Measures line-of-sight 0.03 mm/s Doppler orbiting spacecraft and for certain range rate (60s) astronomical observatories.

Measures line-of-sight LEOP, cruise, approach, planetary Range ~1-2 m range ephemeris updates

Measures plane-of-sky 0.17 mrad LEOP, usable only in the proximity Angles position 0.01 deg of the Earth

Measures plane-of-sky 2.5 nrad Cruise, approach, planetary DDOR position 0.14 μdeg ephemeris updates

Angular resolution 1.7 μrad Approach, proximity, Optical down to about 0.1mdeg 0.1 mdeg ephemeris updates

DSN navigation is the state of the art in deep space nav technology FUTURE OF DEEP SPACE NAVIGATION The Space Navigation Process

Trajectory Design Tools Navigation S/W

Sun Gravity Fields Dynamic Solar System Models Ephemerides Solar Torques, Media Calibrations Thruster Firings Platform Parameters Observational Solar System Models Ephemerides Radio Source Locs Predicted Obs Flight Path KEOF Estimation Compar e Radio Metric Tracking: Media Line of Sight: Range, Doppler Modeling Data Fit No Plane of Sky: VLBI Types OK? Radio Yes Ref Earth Flight-Path Guidance GDHF/ Optimization Commands Analysis Freq. &

Weather Timing GPS Observations (Doppler, Range, Interferometric, Optical) Data VLBI FUTURE OF DEEP SPACE NAVIGATION Advanced Ground-Based Radio-Metrics

Advance ground-based radio-metric navigation capabilities: • Retain and improve interferometric techniques (plane-of-sky observables): – Ka-band DDOR by 2005 – Operational VLBA spacecraft tracking by 2008 – DSN Array by 2012 – Improved real-time media and platform calibrations by 2012 • Retain and improve high-precision ranging and Doppler (line-of-sight observables): – High-precision multi-frequency antenna calibration by 2008 – Pseudorandom-noise coding by 2010 – Improved frequency and timing systems at the DSN array by 2012 – Regenerative digital range transponders by 2012 Advantages: • Improved accuracy for mission critical applications: – Improve precision on approach of Mars by using multi-spacecraft VLBI and range – Improve precision for orbiters by using Ka-band • Reduced use of ground antenna time for routine operations – End the reliance on long sessions of line-of-sight measurements for long-arc dynamical fits, get instantaneous 3-D positions of spacecraft Enhanced navigation capabilities: • Orbit control accuracy on approach for terrestrial and outer planets • Orbit control accuracy in orbit • Orbit reconstruction accuracy in orbit FUTURE OF DEEP SPACE NAVIGATION Advanced Frequency and Timing Systems

• Advance frequency and timing systems: – Improved frequency references for high-precision applications • Systematic upgrades of obsolescent components of DSN’s Frequency and Timing Subsystem, including improved time and frequency systems for BWG arraying by 2006 • Improved time and frequency system for the DSN Array by 2008 – On-board USOs for 1-way tracking using ground or in-situ assets • One-way spacecraft-to-spacecraft applications by 2009 (MTO) • Multiple spacecraft per antenna for telemetry and navigation by 2005 (MGS and MRO) • On-board use of ground-to-spacecraft from a Mars beacon by 2011 • Advantages: – Reduce uplink needs, e.g. Multiple Spacecraft per Antenna – Reduce power requirements, e.g. 1-way uplink data types processed on-board – Improve accuracy of 1-way data, ground-based and in-situ • Enhanced navigation capabilities: – Orbit control accuracy on approach for terrestrial and outer planets – Orbit control accuracy on orbit – Orbit reconstruction accuracy in orbit – Landing accuracy on surface – Position determination of landed vehicles • Enabled mission classes: – Precision landers and rovers – Ascent vehicles – Rendezvous and docking in outer space – Missions that need to navigate autonomously FUTURE OF DEEP SPACE NAVIGATION Future of the DSN: Medium to Long Term

• How to proceed with existing DSN capabilities: – Refurbish, replace (with what?), or? – How long S, move to X, and 26 GHz Ka • X to Ka for many missions is driven by need for bandwidth (not performance) • 26 GHz need to start using it or we will loose it for scientific missions • Optical communications – Mars '09 Telecom Orbiter Experiment Established by NASA – Hard to predict what will follow '09 • GSFC pushing back side of TDRSS space based • Dedicated Space based more flexibility but very high cost? – Ground based may have cost, capacity, and flexibility advantage • Large Array – Still best candidate for affordable >10 x 70m RF based capability – Must have prototype to prove viability for cost and reliable, long life operations – Programmatic uncertainty make start date uncertain FUTURE OF DEEP SPACE NAVIGATION Optical Systems

• Expand usage of optical data for trajectory determination: – Light-weight gimbaled optical camera by 2005 – Opti-metric data types by 2015 • Advantages: – Enabling of close-proximity operations and autonomy, especially when the round-trip light time to the ground would make closed-loop control impossible – Improved navigation accuracy, e.g. pinpoint landing – Complementary or supplementary data types to radio-metric data for applications that require redundancy – Gimballing reduces sequencing conflicts with other spacecraft activities – Reduced use of ground antenna time for navigation • Enhanced navigation capabilities: – Orbit control accuracy on approach for terrestrial and outer planets – Orbit control accuracy on orbit – Landing accuracy on surface • Enabled mission classes: – Low energy orbit transfers – Precision landers & rovers, including proximity operations around small bodies – Rendezvous and docking in outer space – Missions that need to navigate autonomously