National Aeronautics and Space Administration “Keeping the universe connected.” Communicating with Light: A New Dawn in the Information Age Dr. Daniel Raible John H. Glenn Research Center at Lewis Field www.nasa.gov Our Journey of Discovery New Vistas, New Perspectives NASA seeks answers to profound questions using space data E-ring formed from salt-water jets • How and why are Earth’s climate and the environment changing? at the south pole of Enceladus • How and why does the Sun vary and affect Earth and the rest of the solar system? • How do planets and life originate? • How does the universe work, and what are its origin and destiny? The Day the Earth Smiled July 19, 2013 • Are we alone? Our Cosmic Exploration http://www.nasa.gov/connect/apps.html First Television Picture From Space TIROS-1 Satellite April 1, 1960 Solar Flares: Space ‘Weather’ http://stereo.gsfc.nasa.gov/ http://iswa.ccmc.gsfc.nasa.gov/iswa/iSWA.html Click on image to play video Over three days in 2012, a large active region erupted over a dozen solar flares. STEREO spacecraft imaged a X5 flare (X5 is the largest category) in the deep UV region, and a storm of charged particles as part of a coronal mass ejection (CME). Solar Flares: Space ‘Weather’ Q: How long does it take the light from a solar flare to reach Earth, 1.0 Astronomical Units (AU) away (149.6 million km)? A: About 8 minutes Q: How long does it take the Radio Frequency (RF) communication signal from a spacecraft at the sun to reach Earth? A: About 8 minutes, the same as the speed of light! Q: How long does it take a CME to reach Earth? A: About 1-3 days (similar to super-sonic solar winds) Q: How can you observe periods of high solar activity from your backyard? A: Aurora Borealis Highly energetic CMEs will release significant amounts of plasma and accompanying radiation into the solar wind, on the order of terawatt scale, which is directed toward Earth's upper atmosphere. Martian Sunset Click on image to play video Complete Mars Curiosity Descent, Landing and Heat Shield impact Click on image to play video August 6, 2012, 05:17:57 UTC Aeolis Palus in Gale Crater, Mars Full-resolution video of the NASA Curiosity rover descent to Mars and landing, as taken by the MARDI descent imager. Where were you when Curiosity landed on Mars? Curiosity Destination: Mount Sharp http://www.nasa.gov/mission_pages/msl Image looking south of the rover's landing site towards Mount Sharp. The colors are modified as if the scene were transported to Earth and illuminated by terrestrial sunlight. This processing, called "white balancing," is useful for scientists to be able to recognize and distinguish rocks by color in more familiar lighting. This composite was transmitted at a rate of 32 kbit/s. Click on image Juno Perijove May 2017 to play video Cyclones at the Poles of Jupiter Limited to 40 MB of JunoCam data during each 11-day orbital period (10 - 100 images depending on compression level) 10 Click on image to play video Saturn’s Polar Vortex Tx to Earth 40-164 kbit/s Shepard moon causing ripples in rings Cassini - Huygens descent into Titan Forming a Communications Relay Network Click on image to play video New Horizons at Pluto July 23, 2015 At 2.0 kbps data rate from Pluto, it took over a year to transmit all of the images from the flyby back to Earth Voyager 1 Radio Signal Currently Transmitting at 159 bits per second Actual VLBI observation of the 22 W tx Beyond our heliopause, entering interstellar space. One of the greatest moments in human history, delivered by the DSN. Hubble Space Telescope June 8th, 2017: Einstein’s general theory of relativity: ‘gravitational microlensing’ phenomenon confirmed in measure of distant white dwarf star’s mass (Stein 2051 B) through a very rigorous observational test Hubble’s Fine Guidance Sensors enable 34 nano-radians of pointing capability Spitzer Space Telescope Infrared Telescope Observations Seven planets orbiting TRAPPIST-1, an ultracool dwarf star about 40 light-years (235 trillion miles) from Earth Near Earth Objects Survey Program 70 meter antenna (DSS-14) – 2nd most powerful radar (after Puerto Rico Arecibo dish) ▪ Determine locations, rotations and line of sight velocities of asteroids to precisely calculate orbits ▪ Produce images of around 30 asteroids per year Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) mission has released its third year of survey data of asteroid and comet discoveries. Going Forward Video from Philae lander of dust and cosmic rays on the surface of the comet in 2016, with stars moving in the background Asteroid 25143 Itokawa observed from JAXA’s Hayabusa spacecraft in 2005 Image of Mars from ISRO Comet 67P/Churyumov–Gerasimenko Mangalyaan orbiter observed from ESA’s Rosetta spacecraft Russian Venera-13 color image of the surface of Venus Total Current NASA Science Missions / Spacecraft Downpour of Data Imaging and remote sensing data generation is outpacing our capability to transmit to Earth Radiometric Data Measurements using the radio signal and its variations Tracking: Finding and following s/c position Ranging: Round trip light time - distance to s/c (1 m) Doppler: Correlates to s/c velocity (0.01 mm/s) VLBI: s/c angular pose (nano-radian) Space Communications and Navigation Networks What We Across the Globe to Support the Missions Built SCaN 3D Demo http://www.nasa.gov/multimedia/3d_resources/spacecomm.html NetworKing Game SCaN NetworKing A network to communicate with all of the spacecraft …some of the time… http://www.nasa.gov/multimedia/3d_resources/scan.html JPL Space Flight Operations Facility (SFOF) room operating 24/7 for 40 years in Pasadena, CA The SFOF has monitored and controlled all interplanetary and deep space exploration for NASA and other international space agencies since 1963. The facility also acted as a backup communications facility for Apollo missions. 22 Covid-19: Operating a Mars Rover From Home March 20, 2020, the first day the entire NASA Curiosity Mars rover mission team worked remotely from home. 23 Link Performance Examples State of Communications is a Bottleneck for Space Data Return Practice Surface Communications Data Services • Audio* 8-64 kbps/channel (at least 4 channels) • TT&C* < 100 kbps • SDTV Video 6 Mbps • HDTV Video 19 Mbps • Biomedical Control* 70 kbps • Biomedical Monitoring* 122 kbps *Must be Reliable Links MRO: 300 kbps - 4 Mbps 8 – 54 min data rate round-trip light time Hubble: 4 kbps ~0.36 s Cassini: 40 - 164 kbps 2.2 – 3.0 hr STEREO: 427 - 750 kbps ~21.2 min FCC Allocated Frequencies in contention with all the RF users International Spectrum Management in Geneva 25 Equivalent Data Rate from Jupiter 10 10 10 10 10 1 10 10 10 10 6 8 10 12 - - - 2 4 6 4 2 1950 Pioneer IV Pioneer Baseline 1960 3-W, 1.2-m S-Band SC Antenna Reduced Transponder Noise Maser IV Mariner 10-W S-Band TWT 69 Mariner Deep Space Communications Deep Space Communications S 64-m DSN Antenna - 1970 band Reduced Microwv Noise 20-W S-Band TWT, Block Coding Frequency Life Frequency Reduced Ant Surf Tolerances Improved DSN Antenna Data Rate Evolution Rate Data Interplexed, Improved Coding 1.5-m S-/X-Band Antenna X-Band Maser Concatenated Coding 3.7-m X-/X-Band SC Antenna 10 Mariner 1980 Array: 64-m + 1 34-m - Cycle => Cycle Reduced Microwave Noise Video Data Compression) Voyager 64-m to 70-m DSN Antenna 1990 DSN Array: 70-m + 2 34-m X History to date performance improved 10 by improved performance date to History R&D R&D - Galileo band Improved Coding (15/1/6) 2000 Cassini Operational Loss of Galileo Coding Ka-Band, DSN 34-m, SC 3-m antennas Ka Kepler 2010 - 35 W Ka-band Transmitter band DSN Ka-band Array, 3 x 34-m Optical 2020 LDPC Codes and Advanced Compression DSN Ka-band Array, 7 x 34-m Optical Communications 13 Something New: Free-Space Optical Communications (FSOC) Goal: Don’t let communications capability constrain data on our missions • Motivated by present mission needs and RF limitations – Up to 20-fold increase in data rate, enables increased data collection – Optical spectrum unbounded/unregulated, over RF spectrum congestion • Lower transceiver size, weight and power (SWaP) over existing RF solutions – Weight: expensive to launch, ~50% savings in mass (could be reallocated to instruments) – Power: expensive in space, ~65% savings in power (increased mission capability / life) • Component technology is here now • Can transmit while maintaining radio silence during sensitive scientific measurements To transmit a 30 cm resolution “Google Map” of the entire Martian surface (at 1 bit/pixel): Current Ka-band RF system would take 2 years Optical communications can do it in 9 weeks! 27 RF Beam from a Satellite in Geosynchronous Equatorial Orbit (GEO) Electromagnetic beamwidth is ruled by the diffraction limit Beam collimation Footprint (~300 miles) of 0.7° RF beam (1m antenna at 30 GHz) from GEO 28 Optical Beam from Geosynchronous Equatorial Orbit (GEO) Benefits and Challenges A much larger percentage of the Beam collimation transmitted energy goes into the receiver Footprint (~600 meter) of 15 μradian optical beam (4” aperture at 1.55 μm) from GEO + Great for privacy (physical security), can add QKD for additional layer + Higher received energy density = higher data rates (increased SNR) -- …but comes at the cost of very challenging pointing control Clouds and mist can interrupt a laser29 How Small an Angle is a Micro (μ) radian? 8.7 mradians Apparent Sun or Moon size from Earth 290 μradians Limit of human visual acuity, a penny at 4 km 145 μradians Jupiter from Earth Jupiter and four moons