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

2. 1.Scope 2.Requirements for the Communications 3.Critical Parameters 4.Case by Case Analysis 5.Summary 6.Optical Communications 7.Conclusions

3. 1.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 Odissey, source: NASA/JPL Mars Telecommunications Orbiter, source: NASA/JPL

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

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

7. Missions Survey 2. Requirements for the Communications MissionYear / AgencyData Rate to Earth Mars Global Surveyor1996 / NASA~10kbps Mars Odyssey2001 / NASA~14kbps Mars Express2003 / ESA~97kbps Mars Reconnaissance Orbiter2005 / NASA~200kbps Mars Telecommunications Orbiter2009 / NASA~1Mbps 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 (  v) 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  v for insertion

11. 4. Case by Case Analysis High Elliptical Orbit Higher coverage Continuous communication possible with two satellites Low  v 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  v 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  v needed

17. 5. Summary OrbitBit RateCoverageComments/Pro’s/Con’s LMOlow Big Constellation needed/ Low cost / Low performance MMOhighmed Constellation needed / better performances / High cost HEOhighmed/ high > two S/C needed / Low cost/ Performances are limited Stationaryvery highhigh > two S/C needed / Best performances / Very high cost Trojansmed For Mars occultations

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  v 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?