Data Relay Systems for a Mars Human Base in Meridiani Planum L. Nikulásdóttir T. Velasco

1. Data Relay Systems for a Mars Human Base in Meridiani Planum L. Nikulásdóttir T. Velasco

2. Scope • Requirements for the Communications • Critical Parameters • Case by Case Analysis • Summary • Optical Communications • Conclusions

3. Scope • Scope of the Study: • Identify the Requirements and Criticalities for Communications with the Mars Surface • Analyse the Main options for Mars-Earth Relay Satellite • Identify the best Strategy for a Mars Human Base in Meridiani Planum Base Meridiani Planum is located close to the Equator (1.9S; 354.5E)

4. 2. Requirements for the Communications • Current Systems – not communication satellites • NASA Mission Mars Telecommunications Orbiter (2009) • Demanding Requirements for a Human Mission Mars Telecommunications Orbiter, source: NASA/JPL Mars Odissey, source: NASA/JPL

5. 2. Requirements for the Communications • High Data Rate Communications • High Data Volume Communications

6. 2. Requirements for the Communications • “Continuous” Communications - occultations • Reliability of the System

7. 2. Requirements for the Communications • Missions Survey Data rates from Mars orbiting spacecraft to Earth. Values are estimated for the maximum distance Earth to Mars

8. 3. Critical Parameters for Communications • Data Rates • Link Visibility Mars Surface to Earth • Link Visibility Mars Surface to Relay Satellite • Link Visibility Relay Satellite to Earth • Technical Feasibility (by 2019) and Costs (Dv) • Reliability/Redundancy

9. 4. Case by Case Analysis • Low Mars Orbit • Used for MER through Mars Odissey and MGS • Typically 400km – Polar/Sun-synchronous • Low Coverage (2%) • Low Data Volume • Constellations increase performances

10. 4. Case by Case Analysis • Medium Mars Orbit • Increases coverage time • MTO (2009) • Higher Dv for insertion

11. 4. Case by Case Analysis • High Elliptical Orbit • Higher coverage • Continuous communication possible with two satellites • Low Dv required for insertion

12. 4. Case by Case Analysis • Areostationary Orbit • Equivalent to Geostationary orbit for Earth • Continuous coverage of the surface • Two satellites would provide continuous link with Earth • High Dv required • Needs orbit corrections

13. 4. Case by Case Analysis • Mars Moons • Use of Phobos or Deimos orbiters • Performances are not very high

14. 4. Case by Case Analysis • Mars Occultation • The Sun or Moon is between Mars and the Earth • Occultation by the Moon is short (28 minutes) • Occultation by the Sun can happen each approx. 2 years, and can last up to 3 weeks • Occultation by the Sun will not occur in 2019 nor 2021

15. 4. Case by Case Analysis • “Trojan” Orbit • Satellite located in L4 or L5 Earth-Sun Lagrange points • Not optimal performances, but solves the problem of occultation

16. 4. Case by Case Analysis • Lagrange Points • Use L1 and L2 Sun-Mars • Good coverage • Low data rates (high distance from Mars orbit) • High Dv needed

17. 5. Summary

18. 6. Optical Communications • Limitation of the RF Systems • Limitation of the Bit Rates – increasing absorption • Laser Communications are the alternative • Technical Challenges: accurate pointing, cloud and dust attenuation, components, etc • Mars Telecommunications Orbiter – Mars Laser Communications Demonstration (MLCD) MTO Laser communications, source: NASA/JPL

19. 7. Conclusions and Recommendations • High Bit Rate and Continuous Coverage are Mandatory for a Human Mission on Mars • Constellation of HEO or Areostationary seems to be the best solution. HEO is preferred for the low Dv needed for insertion • Further Work to Optimise the Concept (Failure Recovery Modes) • Development of Optical Communications would be big step forward

20. The end or… …The Beginning?