1. Space & Planetary Robotics Group Aerobots for Planetary Exploration Dave Barnes Head of Space Robotics Department of Computer Science Aberystwyth University

2. Space & Planetary Robotics Group Planetary Exploration Methods: Orbiters – MGS, Mars Express Landers – Viking Lander I, II, Beagle 2 Rovers – Spirit, Opportunity, ExoMars Aerobots – Flying robots (The Future)

3. Space & Planetary Robotics Group Aerobot Advantages: High resolution surface imaging Can touch (land) as well as see (image) Landing site selection Rover guidance Data relay Sample site selection Payload delivery and surface science Atmospheric science Can go where rovers cannot!

4. Space & Planetary Robotics Group Aerobot Challenges: Mass/volume/power – (always a challenge!) Aerobot deployment (HTA versus LTA) Constantly changing environment Localisation – Correlate science with Lat./Long./Alt.

5. Space & Planetary Robotics Group Localisation Challenge: No GPS! Cannot always see the stars Anomalous localised magnetic regions Cannot commit orbital resources full time Cannot commit terrestrial “ “ “ Line-of-sight not always possible

6. Space & Planetary Robotics Group ESA Martian Balloon Project:

7. Space & Planetary Robotics Group Aberystwyth Robotic Gondola:

8. Space & Planetary Robotics Group FEATURE AND GRADIENT MATCHING METHODS USED Local Aerobot Generated DEM

9. Space & Planetary Robotics Group Local DEM (Aerobot) Global DEM (Orbiter)

10. Space & Planetary Robotics Group Global DEM DemoShell

11. Space & Planetary Robotics Group Acceptance Trials at the ESA ESTEC Mars Yard Facility

12. Space & Planetary Robotics Group Tethered Aerobot Payload Calculations: Displaced_Mars_atmosphere_mass × Mars_gravity = Total_balloon_mass × Mars_gravity Neutral Buoyancy (N.B.) Example Point of N.B. millimetres Kg Balloon lift in this region

13. Space & Planetary Robotics Group Neutral Buoyancy Equation: ρA = Density of Martian atmosphere ρHe = Density of Helium on Mars ρE = Density of envelope E t = Thickness of envelope M science = Mass of science M tether = Mass of tether M notional = Contingency mass radius = Envelope radius Mass of Displaced atmosphere Mass of Helium in Envelope Mass of Balloon Envelope

14. Space & Planetary Robotics Group Engineering Data: Density of Helium at landing site (ρHe)1.198 × 10 -3 kg/m 3 Density of Martian atmosphere at landing site (ρA)0.013 kg/m 3 Density of HDPE envelope (ρE)0.95 × 10 3 kg/m 3 Thickness of HDPE envelope (Et)0.008 × 10 -3 m Mass of Kevlar-49, 0.25 mm diameter per km (Tether)0.288 kg/km Assume a) High Density Polyethylene (HDPE) envelope b) Tether is made from Kevlar-49 material c) 20% mass contingency For a given envelope radius and tether length (i.e. balloon altitude in Km), then the mass of the science payload can be calculated: 20% contingency (Use Ideal Gas Law to calculate atmosphere and Helium densities on Mars)

15. Space & Planetary Robotics Group The Next 50 years (or less!): Aerobots will be used routinely for planetary exploration Aerobots will work with surface resources (e.g. rovers) Aerobots will be used on Mars, Titan, Venus Aerobot swarms (‘flocks’) will be used

16. Space & Planetary Robotics Group Autonomous Co-operant Aerobots: