2009:003 MASTER'S THESIS Information Gathering Strategies for a Combined Martian System of Aerobots and Rovers Yujie Li Luleå University of Technology Master Thesis, Continuation Courses Space Science and Technology Department of Space Science, Kiruna 2009:003 - ISSN: 1653-0187 - ISRN: LTU-PB-EX--09/003--SE Luleå University of Technology & Cranfield University Li, Yujie Information Gathering Strategies for a Combined Martian System of Aerobots and Rovers Department of Space Science & School of Engineering MSc. Thesis Luleå University of Technology & Cranfield University Department of Space Science & School of Engineering MSc Thesis Academic Year 2006-2007 Li, Yujie Information Gathering Strategies for a Combined Martian System of Aerobots and Rovers Supervisor: Dr. Priya Fernando Dr. Stephen Hobbs Academic Year 2006 to 2007 This thesis is submitted in partial fulfilment of the requirements for the degree of MSc in Astronautics and Space Engineering © Cranfield University, Luleå University of Technology,2007. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder. ABSTRACT Future Mars missions will involve aerial and surface robotics. Previous studies have examined the possibility of using a single robotic balloon in the Martian atmosphere to obtain meteorological and topological data. It may be advantageous, however, to use a combination of aerobots along with surface rovers to map and study Mars. This combined system will be much more effective if the different elements are working in tandem to gather complementary information. The aim of this thesis is to investigate cooperative strategies for exploring a given piece of Martian terrain using a system comprising several different elements. Various aerobot concepts and rovers are reviewed, the capabilities of different types of aerobots and rovers were compared, and a trade-off was made to select a preferred system. Collaboration strategies developed between aerobots and rovers enable them to navigate and explore the target terrain with greater precision and reduced intervention from mission control on Earth. An airship + tethered depot + nanorovers architecture resulted as the best resolution. A suite of instruments were configured to gather useful information. It is concluded that heterogeneous robotics with a complementary suite of instruments work in concert will greatly increase the mission value. Keywords: Mars, Airship, Heterogeneous, Cooperation, Nanorover i ACKNOWLEDGEMENTS I would like to express my thanks to my thesis supervisor Dr. Stephen Hobbs for his invaluable advice and guidance throughout the project. I would also like to thank my friends Niall Dooley, Raza Rizvi for many interesting discussions on a variety of topics and their patience in proofreading my thesis, and thanks to all my friends who have given me support, advice and some well timed distraction when I’m feeling down. Finally I would like to thank my family for their endless support and encouragement that has enabled me to reach the end of my studies, which I could not have done without them. ii TABLE OF CONTENTS ABSTRACT ..................................................................................................................i ACKNOWLEDGEMENTS ..........................................................................................ii TABLE OF FIGURES.................................................................................................. v TABLE OF TABLES ..................................................................................................vi TABLE OF EQUATIONS..........................................................................................vii 1 Project Introduction............................................................................................... 9 1.1 Introduction..................................................................................................... 9 1.2 Objectives ....................................................................................................... 9 2 Mars Exploration................................................................................................. 10 2.1 Past Missions to Mars.................................................................................... 10 2.1.1 Mariner 4 & 6 & 7 – Nasa Mars Flyby (1964-1971)................................ 10 2.1.2 Mars 2 & 3 – Soviet Mars Orbiter and Lander (1971) ............................. 11 2.1.3 Mariner 9 – NASA Mars Orbiter (1971)................................................. 11 2.1.4 Viking Project – NASA orbiters/landers to Mars (1975)......................... 11 2.1.5 Mars Observer – NASA attempted mission to Mars (1992)..................... 12 2.1.6 Mars Pathfinder - NASA lander and rover to Mars (1996) ...................... 12 2.1.7 Mars Global Surveyor - NASA Mars orbiter (1996)................................ 13 2.1.8 Mars Climate Orbiter - NASA attempted orbiter to Mars (1998)............. 13 2.1.9 Mars Polar Lander - NASA attempted lander to Mars (1999).................. 14 2.2 Current Missions ........................................................................................... 14 2.2.1 2001 Mars Odyssey - NASA Orbiter Mission to Mars (2001) ................. 14 2.2.2 Mars Express - ESA Mars Orbiter and Lander (2003)............................. 14 2.2.3 Mars Exploration Rovers - Two NASA Rovers to Mars (2003)............... 15 2.2.4 Mars Reconnaissance Orbiter – NASA Orbiter (2005)............................ 16 2.3 Future Mission .............................................................................................. 17 2.3.1 European Space Agency Mission............................................................ 17 2.3.2 NASA (US) Missions ............................................................................. 17 2.3.3 Future Mission Summary........................................................................ 18 3 Aerial Robots - Aerobots..................................................................................... 19 3.1 Advantages and Applications of Aerobot....................................................... 19 3.1.1 Atmospheric science............................................................................... 19 3.1.2 Payload delivery ..................................................................................... 19 3.1.3 Sample site selection............................................................................... 20 3.1.4 Composition & Subsurface investigation ................................................ 20 3.1.5 Surface imaging & mapping ................................................................... 20 3.1.6 Magnetic environment ............................................................................ 21 3.2 Aerobot Concepts.......................................................................................... 21 3.2.1 Lighter than Air ...................................................................................... 21 3.2.2 Heavier than Air ..................................................................................... 25 3.2.3 Summary: ............................................................................................... 30 4 Surface Robots - Rovers...................................................................................... 32 4.1 Rover Missions.............................................................................................. 32 4.1.1 Lunar Roving Vehicle (LRV) ................................................................. 32 4.1.2 Russian Lunokhod Rover........................................................................ 33 4.1.3 Mars Pathfinder Sojourner ...................................................................... 33 4.1.4 Mars Exploration Rover.......................................................................... 34 iii 4.2 Rover Classification ...................................................................................... 35 4.2.1 Macro rover............................................................................................ 35 4.2.2 Mini rover .............................................................................................. 35 4.2.3 Micro rover............................................................................................. 35 4.2.4 Nano rover.............................................................................................. 36 4.3 Conclusion: ................................................................................................... 37 5 Aerobots and Rovers Collaboration..................................................................... 38 5.1 Mission Objectives and Science Rationale:.................................................... 38 5.2 Background................................................................................................... 39 5.2.1 Terrestrial application............................................................................. 39 5.2.2 Planetary exploration .............................................................................. 40 5.3 Cooperation Strategies................................................................................... 40 5.3.1 Imaging and Mapping:............................................................................ 41 5.3.2 Localisation and Navigation/Route planning:.......................................... 41 5.3.3 Communication: ....................................................................................