Human Spatial Orientation Perceptions during Simulated Lunar Landing By Torin Kristofer Clark B.S. Aerospace Engineering University of Colorado at Boulder, 2008 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 © 2010 Massachusetts Institute of Technology All rights reserved Signature of Author: ____________________________________________________________ Torin K. Clark Department of Aeronautics and Astronautics May 21, 2010 Certified by: ___________________________________________________________________ Laurence R. Young Apollo Program Professor of Astronautics Professor of Health Sciences and Technology Thesis Supervisor Certified by: ___________________________________________________________________ Kevin R. Duda Senior Member, Technical Staff, Draper Laboratory Thesis Supervisor Accepted by: __________________________________________________________________ Eytan H. Modiano Associate Professor of Aeronautics and Astronautics Chair, Committee on Graduate Students 1 ABSTRACT During crewed lunar landings, astronauts are expected to guide a stable and controlled descent to a landing zone that is level and free of hazards by either making landing point (LP) redesignations or taking direct manual control. However, vestibular and visual sensorimotor limitations unique to lunar landing may interfere with landing performance and safety. Vehicle motion profiles of candidate lunar descent trajectories were used as inputs to a mathematical model for orientation system function, to predict human perception of orientation and identify disorientating illusions. Simulations were conducted using the vestibular-only portion of the model as well as incorporating the activation of visual cues. Dust blowback from the descent engine was modeled as well. The NASA Ames Vertical Motion Simulator was used to experimentally investigate human orientation perception during manually controlled landing trajectories. Subjects were tasked with reporting perceptions of vehicle tilt angle and horizontal velocity. There were three treatment conditions studied: eyes closed (blindfolded), eyes out the window on simulated lunar terrain, or eyes on display instruments. It was seen in the vestibular-only orientation perception model that the acceleration profile of the descent engine throughout candidate trajectories is likely to create a somatogravic illusion. This illusion creates the perception of being upright even when the actual vehicle orientation is significantly tilted. The model predicts the underestimation of tilt angle for the candidate automated trajectories as well during maneuvers resulting from LP redesignation and manual control maneuvers. The activation of visual pathways in the model improved orientation perceptions, however misperceptions persisted when visual cues were limited such as prior to the pitch-over maneuver and during dust blowback. Results from the motion base simulator experiment are in agreement with the likelihood of the somatogravic illusion occurring without the astronauts’ continued focus on instrument displays. Horizontal velocity was poorly perceived without reliable visual cues, both in magnitude and direction. Misperception of spatial orientation is likely to increase workload and may reduce performance and safety during landing. Countermeasures should be designed to minimize the risk of astronaut disorientation, including the design of advanced displays. Thesis Supervisor: Laurence R. Young Title: Apollo Program Professor of Astronautics Professor of Health Sciences and Technology Thesis Supervisor: Kevin R. Duda Title: Senior Member, Technical Staff, Draper Laboratory 2 ACKNOWLEDGEMENTS I would like to thank my advisors: Professor Larry Young and Dr. Kevin Duda for giving me the opportunity to do research at the Man Vehicle Lab at MIT and at Draper Laboratory. I appreciate their extensive knowledge and guidance as well as their inspiration in helping me enter this field. I would like to thank Dr. Chuck Oman for his support of this project and my research efforts. I would like to thank Alexander Stimpson for his incredible feedback, problem solving skills, and support. I thank Michael Newman for developing and providing the Observer model as well as his technical support in teaching me how to use it. I would like to thank Dr. Alan Natapoff for the countless hours spent discussing data analysis and statistical techniques as well as Liz Zotos for always knowing how to solve any administrative problems I have had. I would like to thank the faculty and staff of the Man Vehicle Lab for their support and advice. I would like to thank Dr. Karl Bilimoria, Eric Mueller, and Chad Frost for allowing me to join in their Ames Vertical Motion Simulator lunar landing experiment. I also thank the entire VMS staff, in particular Bosco Diaz for his programming support and Khoa Nguyen for help in constructing mounting hardware. I would like to thank Dr. Arthur Estrada for his gracious volunteering as an experimenter for the VMS study. I thank Jessica Marquez for her help in recruiting excellent subjects for the VMS experiment. I would to thank my family and friends for their support. My parents always pushed me and inspired me to do the best at whatever I attempt. They have always believed in me, helping me believe in myself. I thank the incredible community of students in the Man Vehicle Lab which I have the pleasure of working with. This material is based upon work supported by the National Space Biomedical Research Institute through NASA under award No NCC9-58-11, Project SA01604. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Aeronautics and Space Administration. 3 Assignment of Copyright Draper Laboratory Report Number T-1664 In consideration for the research opportunity and permission to prepare my thesis by and at The Charles Stark Draper Laboratory, Inc., I hereby assign my copyright of the thesis to The Charles Stark Draper Laboratory, Inc., Cambridge, Massachusetts. (Author’s Name) (Date) 4 TABLE OF CONTENTS ABSTRACT ...................................................................................................................................................... 2 ACKNOWLEDGEMENTS ................................................................................................................................. 3 Assignment of Copyright ............................................................................................................................... 4 LIST OF ACRONYMS ....................................................................................................................................... 8 LIST OF FIGURES ............................................................................................................................................ 9 LIST OF TABLES ............................................................................................................................................ 12 1 INTRODUCTION ................................................................................................................................... 13 1.1 Motivation ................................................................................................................................... 14 1.2 Contribution ................................................................................................................................ 16 1.3 Problem Statement ..................................................................................................................... 17 1.4 Thesis Outline .............................................................................................................................. 18 2 BACKGROUND ..................................................................................................................................... 18 2.1 The Lunar Landing Task ............................................................................................................... 18 2.2 Challenges of the Lunar Environment ......................................................................................... 22 2.3 Spatial Disorientation in Previous Space Landings ..................................................................... 24 2.3.1 Apollo Lunar Landings ......................................................................................................... 24 2.3.2 Shuttle Landings .................................................................................................................. 25 2.3.3 Future Lunar Landings ......................................................................................................... 27 2.4 Spatial Orientation Sensory Systems .......................................................................................... 27 2.5 The Observer Model ................................................................................................................... 29 2.6 Coordinate Frame ....................................................................................................................... 32 2.7 Head Location Background ......................................................................................................... 33 3 METHODS ...........................................................................................................................................