Communication and Navigation System

1. Communication and Navigation System Doro Gracia Kazuya Suzuki Patrick Zeitouni

2. Mission Requirements • Provide adequate communication between: • Rovers • Emergency transfer vehicles • Bases and waypoints • Provide adequate navigation capability for: • lunar landers • rovers along race route • Establish: communications and navigation infrastructure. USC 2004 AME 557 Space Exploration Architecture

3. Comm Requirements & Issues • High data rates from rovers: • 4 active HDTV channels • 12 Mbps per rover • Continuous Rover coverage • From lunar equator to pole trek • Rovers Limitations: • Power limited, • Earth-Moon distance at that data rate cannot be achieved • Antenna Pointing accuracy a problem during race (bounce) • Complex antennas like phased arrays can solve pointing problem, but are expensive, bulky, and are even more power inefficient USC 2004 AME 557 Space Exploration Architecture

4. Lunar Com Options Trade Study • Looked at laser and radio frequencies (RF) communication • Straight to Earth / Earth orbiting satellites • Through Lunar orbiting satellites • Looked at surface towers • Chose LC to Earth Orbit for Bases & Waypoints • Chose RF to Lunar Orbit for Rovers USC 2004 AME 557 Space Exploration Architecture

5. Rover Com System GEO GEO satellites either advanced TDRSS or commercial satellite equipped with optical head RF LC USC 2004 AME 557 Space Exploration Architecture

6. Rover Com System Details • Rovers have a 0.3m antenna • Rovers communicate to Lunar orbit • Adequate link margin • Relaxed pointing requirement • Satellite Constellation • 0.6m Antenna to Lunar surface, LC back to Earth • 4 satellites in 2 repeating ground track orbits • Inclined (85~90) to service poles • Eccentric (0.6) to dwell longer in south pole • Satellite pairs spaced 180° apart in same orbit to provide handoff USC 2004 AME 557 Space Exploration Architecture

7. Satellite Orbits USC 2004 AME 557 Space Exploration Architecture

8. Rover Coverage USC 2004 AME 557 Space Exploration Architecture

9. Base & Waypoint Com System GEO • Given their fixed locations, bases and waypoints communicate directly to Earth orbit using LC • GEO satellites either advanced TDRSS or commercial satellite equipped with optical head RF LC USC 2004 AME 557 Space Exploration Architecture

10. Earth-Moon Phase Transport Com • Satellite based system with RF com capabilities for: • Communications • between crew transport and Earth • between crew transport and L1 station depending on proximity < 55,000km. • Use a 1m antenna (adequate dB margin) L1 Station USC 2004 AME 557 Space Exploration Architecture

11. TV Programming • TV studios from Earth gateways provide live rover race feed (via satellites) • Continuous 24 hours a day coverage • Daily summaries with highlights of events • Pay-per-view provides: • In-depth analysis • behind the scenes • And more USC 2004 AME 557 Space Exploration Architecture

12. Navigation Mission Requirements • Provide navigation capabilities for the following: • Lunar landings (manned & unmanned) • Rovers • Rescue missions USC 2004 AME 557 Space Exploration Architecture

13. Available Options • Satellites • Towers • Beacons • Inertial systems • Image Terrain Navigation (landmarks) USC 2004 AME 557 Space Exploration Architecture

14. Proposed Systems • Landing navigation at bases • Beacons (like existing airports) • Rover navigation • Image terrain navigation for rovers • Backup guidance for rovers • Inertial systems, recalibrated at waypoints • Earth assistance USC 2004 AME 557 Space Exploration Architecture

15. Proposed Systems • Emergency vehicle navigation • Track the beacons on rovers • Beacons at Waypoints • Assist in emergency or other landings • RF Buoys dropped by rovers • Establish a route that future rovers can follow • Assist in emergency landings USC 2004 AME 557 Space Exploration Architecture

16. Communication Link Budget USC 2004 AME 557 Space Exploration Architecture