USE AND SIZING OF ROCKET HOPPERS FOR PLANETARY SURFACE EXPLORATION BY WENDELIN X. MICHEL OF TECHNOLOGY B.A. PHYSICS, B.A.S. INDIVIDUALIZED JUN 2 3 2010 UNIVERSITY OF PENNSYLVANIA 2004 LIBRARIES M.SC. SPACE STUDIES INTERNATIONAL SPACE UNIVERSITY 2005 ARCHIVES SUBMITTED TO THE DEPARTMENT OF AERONAUTICS AND ASTRONAUTICS IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN AERONAUTICS AND ASTRONAUTICS AT THE MASSACHUSETTS INSTITUTE OF TECHNOLOGY JUNE 2010 COPYRIGHT, 2010 MASSACHUSETTS INSTITUTE OF TECHNOLOGY. ALL RIGHTS RESERVED. SIGNATURE OF AUTHOR: DEPARTMENT OF AERONAUTICS AND ASTRONAUTICS MAY 21, 2010 CERTIFIED BY: v JEFFREY A. HOFFMAN PROFESSOR 0 CTICE OF AEROSPACE ENGINEERING THESIS SUPERVISOR ACCEPTED BY: EYTAN H. MODIANO ASSOCIATE PRO SSOR OF AERONAUTICS AND ASTRONAUTICS CHAIR, COMMITTEE ON GRADUATE STUDENTS USE AND SIZING OF ROCKET HOPPERS FOR PLANETARY SURFACE EXPLORATION BY WENDELIN X. MICHEL SUBMITTED TO THE DEPARTMENT OF AERONAUTICS AND ASTRONAUTICS ON MAY 21, 2010 IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN AERONAUTICS AND ASTRONAUTICS ABSTRACT The utilization of rocket hoppers can provide a valuable means of obtaining enhanced mobility for planetary surface exploration missions. Hoppers offer higher exploration versatility than landers, rovers, or other surface exploration systems through their ability to quickly traverse difficult terrain in a variety of planetary environments. Furthermore, using a hover hop rather than a ballistic hop can provide many operational advantages. As the distance between target sites increases, the advantages of a single hopper compared to multiple landers decreases. However, in certain cases, in-situ resource utilization could overcome this problem. A detailed seven-phase hover hop model, simplified approximation formulas for lunar hops, and an optimization tool are presented in this thesis. With these, it becomes possible to quickly obtain optimized values for the vehicle mass, engine mass, and other mission parameters for a specified hopper mission. Results obtained from the application of a lunar hover hop model to realistic mission scenarios demonstrate the utility of hoppers for tasks relevant to future robotic and human exploration of the Moon. Thesis Supervisor: Jeffrey A. Hoffman Title: Professor of the Practice of Aerospace Engineering CONTENTS C o n te n ts ........................................................................................................................................... 5 . In tro d u ctio n................................................................................................................................ 7 1.1 Survey of Planetary Exploration Systems ............................................................................... 7 1.1.1. Planetary Landers ....................................................................................................... 7 1.1.2. Planetary Rovers ....................................................................................................... 11 1.2 Planetary Surface Exploration Versatility Analysis ...................... ....................................... 13 1.2.1. Establishing a Measure of Exploration Versatility..................................................... 13 1.2.2. Versatility Comparison .............................................................................................. 15 1.3 Hoppers Versus Multiple Landers........................................................................................ 16 1.4 Research Goals for Future Planetary Surface Exploration ............ .............................. 17 I. The Use of Planetary Hoppers................................................................................................. 19 11.1 Hopper Mission Architectures ................................................. 19 11.1.1. Landing System ......................................................................................................... 20 11.1 .2 . Pa y lo a d s ................................................................................................................... 2 0 11.1 .3 . T ra ve rse s .................................................................................................................. 2 0 11 .1.4 . Sta g in g ..................................................................................................................... 2 1 11.2 In-Situ Resource Utilization for Mars Hoppers ................................................................ 21 11.2.1. Hybrid ISRU Systems .............................................................................................. 22 11.2.2. Fully Autonomous Systems ..................................................................................... 23 11.3 Ballistic Hop Versus Hover Hop...................................................................................... 23 Ill. Hover Hop Model and Optimization .................................................................................. 25 I1.1 Hopper Subsystem Models............................................................................................. 25 111.2 Propulsion System ............................................................................................................ 26 111.2.1. Sizing the Engine and Tanks...................................................................................... 26 111.3 Modeling a Hover Hop .................................................................................................. 29 111.4 Fundametal Equations of a Hover Hop Model ................................................................ 30 111.5 Input Parameters .............................................................................................................. 31 111.6 Subsystem Models ............................................................................................................ 31 111.7 Description of the Hopper State..................................................................................... 32 111.8 Phase 1 -Vertical Ascent............................................................................................... 33 111.9 Phase 2 - Horizontal Acceleration.................................................................................. 34 111.10 Phase 3 - Hover with Acceleration ............................................................................. 34 111.11 Phase 4 - Horizontal Coast ......................................................................................... 36 111.12 Phase 5 - Hover with Deceleration.............................................................................. 36 111.13 Phase 6 - Horizontal Deceleration ............................................................................. 37 111.14 Phase 7 - Vertical Descent ........................................................................................... 38 111.15 Hover Hop O ptim ization Requirements ..................................................................... 39 111.16 O ptim ization of Hopper M ass ....... ...... .................................................................... 40 111.17 Description of a Hopper O ptim ization Tool ................................................................ 41 111.18 Description of the Hop Analysis Space........................................................................ 41 IV. Lunar Hop Analysis .............................................................................................................. 43 IV.1 Dependency on Fixed Payload M ass ............................................................................... 43 IV.2 Single-Hop Equivalent Distance and Payload ....... ................... ..................................... 44 IV.3 Equivalent Distance and Payload Variation ............................... ................................... 46 IV.4 Com parison of Hover Hop Results with Landers .............................................................. 60 IV.5 Applying the Lunar Hopper Sizing Models....................................... 62 IV.5.1. Exploring the Lunar South Pole Region .................................................................... 63 IV.5.2. Supporting Human Surface O perations .......... ..................................... 67 IV.5.3. Deploying a Large Sensor Network ........................................................................ 68 V. Lim itations, Future W ork, and Conclusions ........................................................................ 71 V.1 Lim itations and Future W ork........................................................................................... 71 V.2 Conclusion ....................................................................................................................... 72 Appendix: Hover Hoptim izer Documentation....................... .......................................... 73 A.1 System Requirements........................................................................................................ 73 A.2 Starting the Program ........................................................................................................ 73 A.3 Program Overview............................................................................................................ 74 A.4 Running an O ptim ization............................................................................................... 76 A.5 Hopper M ode and Lander M ode....................................................................................