Data communication and Mars missions

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The communication systems is an essential component of a mission and its role on scientific instruments.

The evolution of the type of data, their usage since the first Mars missions and their roles on these missions have evolved and will be described during this presentation
The data communication usage, evolution will be presented from a technical and utilization point of view, and what are the advantages and limits of the current systems confronted to the current technological limits
and its usage in a space environments.

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Data communication and Mars missions

  1. 1. Image Credit: IPNSIGData communication and Mars missions Stephan Gerard Association Planète Mars (APM) stephan.gerard@laposte.net 12th European Mars Conference EMC12 – Munich - 13 Oct 2012
  2. 2. Summary1) Introduction2) Data Communication3) Communication infrastructure4) Mars missions5) Mission data6) Future communication technologies7) Conclusion8) Questions S. Gerard - EMC12 Munich - 13 Oct 2012 2
  3. 3. IntroductionIf no communication: => no data transmitted to Earth => no scientific data => we have a problem !!! S. Gerard - EMC12 Munich - 13 Oct 2012 3
  4. 4. Data Communication Mars communication challenges● Large transmission delays RTT between Earth and Mars varies between: ● 7min and 46min● Great distance ● between 55.7 and 401.3 million km● Limited bandwidth available● Disrupted links (orbital visibility) S. Gerard - EMC12 Munich - 13 Oct 2012 4
  5. 5. Data Communication Mars communication challenges● Error rates● Noisy communication links● Limited time frame● Power available on lander or rover● Buffer capacity S. Gerard - EMC12 Munich - 13 Oct 2012 5
  6. 6. Data Communication Communication systems2 types of communications: ➢ “Long Haul” between Mars and Earth ➢ “Short Haul” or “Proximity” between the orbiter and Mars surfaceAntennas:● Low gain antenna is omni-directionnal used as a backup to high gain antenna● High gain antenna is directionnal S. Gerard - EMC12 Munich - 13 Oct 2012 6
  7. 7. Data Communication CCSDS● CCSDS = Consultative Commitee for Space Data Systems● Multi-national forum since 1982.● CCSDS has its 30th anniversary this year.● Develop standards for space data communications.● CCSDS has been founded by 11 space agencies. S. Gerard - EMC12 Munich - 13 Oct 2012 7
  8. 8. Data Communication CCSDS● CCSDS standards independent of the underlaying bus architecture.● ESA mandates that all missions to be CCSDS compatible.● Proximity-1 Space Link protocol (UHF1) is the standard used for relay communications by all the missions currently at Mars since Mars Odyssey and is designed to ensure error-free delivery of data. S. Gerard - EMC12 Munich - 13 Oct 2012 8
  9. 9. Data Communication Radio frequenciesX-band: ● microwave frequency Transmit: 7145MHz-7190Mhz Receive: 8400MHz-8450Mhz ● current standard in communications ● is used for long range communications ● used between rovers and Earth S. Gerard - EMC12 Munich - 13 Oct 2012 9
  10. 10. Data Communication Radio frequenciesUHF band: ● Ultra High Frequency (300 to 3 000 MHz) from 390 to 450MHz on Mars missions ● used between landers, rovers and orbiting spacecrafts S. Gerard - EMC12 Munich - 13 Oct 2012 10 1
  11. 11. Data Communication Radio frequenciesKa-band:● microwave frequency Transmit: 34200MHz-34700MHz Receive: 31800MHz-32300MHz● used as a secondary link between landers and orbiters● previously untested radio frequency● Frequency x 4 allow an higher data rate than using X-band S. Gerard - EMC12 Munich - 13 Oct 2012 11 1
  12. 12. Image Credit: NASA / JPLTelecommunications for Mars Rovers and Robotic Missions S. Gerard - EMC12 Munich - 13 Oct 2012 12 1
  13. 13. Communication infrastructure DSN - Deep Space Network NASA / JPL● DSN is present in 3 locations (Goldstone, Madrid, Canberra) to have full day coverage.● DSN has extremely large antennas: - 70 meter - 34 meter HEF (High Efficiency) S. Gerard - EMC12 Munich - 13 Oct 2012 13 1
  14. 14. Communication infrastructure DSN Deep Space Network NASA / JPL Mars missions are not the only mission using interplanetary communications infrastructure.Communication time frame windows must be shared with the other missions. S. Gerard - EMC12 Munich - 13 Oct 2012 14 1
  15. 15. Communication infrastructure ESTRACK ESA Tracking Station Network● Only New Norcia, Cebreros and Malargüe have or will have 35 meter deep-space antennas● 35m Deep Space Antenna stations primarily use the X-band● S-band (2025-2300 Mhz), Ka (18.1-32.3 GHz) and X-Band (7145-8500 Mhz)● Data rates vary depending on the mission but typically range from 256 Kbit/s to 8 Mbit/s S. Gerard - EMC12 Munich - 13 Oct 2012 15 1
  16. 16. S. Gerard - EMC12 Munich - 13 Oct 2012 16 1
  17. 17. Mars missions Current active missionsMars Odyssey (ODY) (2001 – USA)Mars Express (MEX) (2003 – EU)Opportunity (MER-B) (2003 – USA)Mars Reconnaissance Orbiter (MRO) (2005 – USA)Mars Science Laboratory (MSL) (2011 – USA) S. Gerard - EMC12 Munich - 13 Oct 2012 17 1
  18. 18. Mars missions Viking 1 & 2 ➢ Sent data directly back to Earth using UHF relay radio but most often via the Viking orbiter ➢ Science data rate via relay orbiter at 250, 500, and 1000 bits/sImage Credit: NASA ➢ Science data rate via direct link at 250, 500, and 1000 bits/s S. Gerard - EMC12 Munich - 13 Oct 2012 18 1
  19. 19. Mars missions Pathfinder rover “Sojourner” ➢ UHF radio systems ➢ Direct communication from Mars surface to Earth ➢ Limited transmitter ➢ Communication weak and data reliability limited ➢ Limited data rateImage Credit: NASA S. Gerard - EMC12 Munich - 13 Oct 2012 19 1
  20. 20. Mars missions Mars Odyssey Orbiter ➢ Odyssey is used as a data relay ➢ UHF and X-band frequencies ➢ X-band transfer rates of up to 128 kb/s ➢ Has approx. 260Mbit of memory allocated for surface vehicule.Image Credit: NASA/JPL-Caltech S. Gerard - EMC12 Munich - 13 Oct 2012 20 2
  21. 21. Mars missions MER rover “Opportunity & Spirit” ➢ X-band & UHF systems ➢ Use Proximity-1 (Prox-1) protocol for relay communications ➢ 120 Mbits allocated onboard memory of Mars Odyssey ➢ Data rate using UHF: 8, 32,Image Credit: NASA/JPL/Cornell University 128, 256 kbps S. Gerard - EMC12 Munich - 13 Oct 2012 21 2
  22. 22. Mars missions Mars Express ➢ MEX is used as a data relay ➢ UHF and X-band frequencies ➢ Use Proximity-1 protocolImage Credit: ESA S. Gerard - EMC12 Munich - 13 Oct 2012 22 2
  23. 23. Mars missions Phoenix Mars Lander ➢X-band & UHF system ➢ Use Proximity-1 (Prox-1) protocol ➢ Data rate UHF: 8, 32, 128, 256 kbps ➢ Can use MEX orbiter as backup data relayImage Credit: NASA/JPL S. Gerard - EMC12 Munich - 13 Oct 2012 23 2
  24. 24. Mars missionsMars Science Laboratory rover “Curiosity” 1st rover to have an Electra transceiver ➢ X-band & UHF system ➢ Use MRO and ODY as data relay ➢ Cross support with MEX ➢Use Proximity-1 Space Link Protocol (Prox-1)Image Credit: NASA/JPL-Caltech ➢ Use “store-and-forward” mode of communications S. Gerard - EMC12 Munich - 13 Oct 2012 24 2
  25. 25. Mars missionsMars Reconnaissance Orbiter ➢ MRO is used as a data relay ➢ Use X-band and Ka-band ➢ can send data back to Earth > X 10 than previous missions. ➢ sends data to Earth for 10 to 11 hours per day ➢ Data rates: from 0.5Mbits/s Image Credit: NASA/JPL to 4 Mbits/s ➢ Predicted total amount of data: 34 terabits S. Gerard - EMC12 Munich - 13 Oct 2012 25 2
  26. 26. MER telecommunication architecture Image Credit: NASA / JPL S. Gerard - EMC12 Munich - 13 Oct 2012 26 2
  27. 27. Mars missions Orbiters as data relay with Earth● Mars Odyssey acts as a data relay for MER.● Currently, ODY, MEX and MRO are used as data relay for Mars missions.● MRO is able to send data back to Earth more than 10 times faster than previous missions.● Future ExoMars orbiter will also act as a data relay in jan 2019 S. Gerard - EMC12 Munich - 13 Oct 2012 27 2
  28. 28. Mars missions Data transferred from MarsAmount of data received from Mars via MRO 177 223 Terabits 1 Terabits = 10 power 12 bits S. Gerard - EMC12 Munich - 13 Oct 2012 28 2
  29. 29. Missions data Data ratesMRO● A 3 meter long high gain antenna and 100 watt.● 160 gigabits of solid-state memory● Data rate at a maximum of around 6 Mbit/s when the distance between Earth and Mars is minimum (55.7 million km)● Data rate at a minimum of 0.6 Mbit/s when the distance between Earth and Mars is maximum (401.3 million km)● Time of transmission during science phase: 8h/day S. Gerard - EMC12 Munich - 13 Oct 2012 29 2
  30. 30. Missions data Data ratesMartian rovers can send data Direct To Earth (DTE) ata rate from 3.5kb/s to 12kb/s.Data rate to an orbiter is at constant rate of 128kbit/sbut varies between 128kb/s or 256kb/sThe rover can only transmit direct to Earth for around3h/day due to power and thermal limitations.Odyssey can also operate in bent-pipe mode: downlinkto Earth while at the same time receiving data fromlanders using UHF system. S. Gerard - EMC12 Munich - 13 Oct 2012 30 3
  31. 31. Missions data Data ratesA rover communicate with an orbiter during 8min/solFor comparison, in 8min, 60Mb could be transmittedduring a sol.The same 60Mb would take between 1.5h and 5h totransmitted direct to Earth.InSight mission is planned to send more than 29Gb in1 Martian year. S. Gerard - EMC12 Munich - 13 Oct 2012 31 3
  32. 32. Future communication technologies Mars communications projects● The purpose of these new projects are: ➢ to reduce time latency between Earth and the remote mission spacecraft ➢ to improve reliability and reduce errors code transmission S. Gerard - EMC12 Munich - 13 Oct 2012 32 3
  33. 33. Future communication technologies Mars communications projectsTo improve data bandwidth which increase withbetter onboard instruments and new needs.Test new technologies like Laser Communication andnew protocols (DTN) S. Gerard - EMC12 Munich - 13 Oct 2012 33 3
  34. 34. Future communication technologies Optical space communicationsOptical space communication also know as lasercommunication or lasercom● A demonstrator is currently done with Laser Communications Relay Demonstration (LCRD).● The lasercom system would increase the data rate to 100Mbps.● A high resolution image would arrive on Earth in 5 minutes rather than in 90 minutes using MRO.● MAVEN mission will use optical communications S. Gerard - EMC12 Munich - 13 Oct 2012 34 3
  35. 35. Future communication technologiesOptical space communications Image Credit: JPL/CalTech S. Gerard - EMC12 Munich - 13 Oct 2012 35 3
  36. 36. Future communication technologies Delay Tolerant Network (DTN)● The InterPlanetary Network (IPN) is also associated in DTN project.● Demonstrators are currently running on ISS● Store and forward methodFactsheet - Disruption Tolerant Networking for Space Operations (DTN)http://www.nasa.gov/mission_pages/station/research/experiments/DTN.html S. Gerard - EMC12 Munich - 13 Oct 2012 36 3
  37. 37. Future communication technologies IPNSIG● IPNSIG (InterPlanetary Networking Interest Group)● A communication system with networking protocols to handle signal delay and connectivity disruption● The Space Internetworking Strategy Group has published a document the document “Operations Concept for a Solar System Internetwork (SSI)” in October 2010 ( IOAG.T.RC.001.V1 ) S. Gerard - EMC12 Munich - 13 Oct 2012 37 3
  38. 38. Future communication technologies IPNSIG Image Credit: IPNSIGThe red-dotted data flows use DTN protocols.TCP/IP or other low latency protocols are the yellow andblue-dotted data flows. S. Gerard - EMC12 Munich - 13 Oct 2012 38 3
  39. 39. ConclusionSince the 1st missions to Mars, the amount of data transmitted to Earth has increased a lot. More bandwidth are neededData communications are an important part of the mission. Data are used by the scientific communities and also for public outreach. S. Gerard - EMC12 Munich - 13 Oct 2012 39 3
  40. 40. Conclusion Usage of CCSDS communication standards. New technologies and standards are currentlytested to allow more and more data to be send back to Earth with a minimum of disruption. Communication is a key element for future missions on Mars. S. Gerard - EMC12 Munich - 13 Oct 2012 40 4
  41. 41. QuestionsS. Gerard - EMC12 Munich - 13 Oct 2012 41 4
  42. 42. Image Credit: NASA / JPL / CaltechS. Gerard - EMC12 Munich - 13 Oct 2012 42 4
  43. 43. References Mars missions – JPL / NASA http://mars.jpl.nasa.gov/ NASA – Space Communications and Navigation https://www.spacecomm.nasa.gov/ CCSDS Consultative Committee for Space Data Systems http://public.ccsds.org IPNSIG InterPlanetary Networking Special Interest Group http://ipnsig.org DTNRG Delay-Tolerant Networking Research Group http://www.dtnrg.org DESCANSODeep Space Communications and Navigation Systems Center of Excellence http://descanso.jpl.nasa.gov S. Gerard - EMC12 Munich - 13 Oct 2012 43 4

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