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Robots and Humans: An Integrated Approach

Most concepts for Moon/Mars exploration envision a mix of robots and humans. However, the criteria for deciding how each of them should be used, and in what combination, are not usually stated and probably were never formally developed. The result is that the concepts are biased according to the background of the study group; human exploration advocates tend to minimize the use of robots, whereas traditional space scientists tend to downplay the potential of human presence. CHEX believes that decisions regarding the mix of robots and humans to explore the Moon and Mars, and to carry out other scientific investigations in space, should be made with explicit cognizance of the relative strengths and weaknesses of each evaluated in the context of well-defined and specific tasks to be performed.

RELATIVE ADVANTAGES

Human presence can bring to planetary exploration a level of capability representing an essential aspect of scientific methodology: an iterative process of observing, hypothesizing, testing, and synthesizing. Activities ideally suited to humans include those requiring the techniques of intensive field study and tasks requiring complex, physical articulation combined with expert knowledge and the ability to adapt to new situations. Humans conducting scientific observations on planetary surfaces can perform their work with an inherent flexibility not easily equaled by the more cumbersome and delay-ridden methods of remote control, especially at significant radio-de-



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Scientific Opportunities in the Human Exploration of Space 2 Robots and Humans: An Integrated Approach Most concepts for Moon/Mars exploration envision a mix of robots and humans. However, the criteria for deciding how each of them should be used, and in what combination, are not usually stated and probably were never formally developed. The result is that the concepts are biased according to the background of the study group; human exploration advocates tend to minimize the use of robots, whereas traditional space scientists tend to downplay the potential of human presence. CHEX believes that decisions regarding the mix of robots and humans to explore the Moon and Mars, and to carry out other scientific investigations in space, should be made with explicit cognizance of the relative strengths and weaknesses of each evaluated in the context of well-defined and specific tasks to be performed. RELATIVE ADVANTAGES Human presence can bring to planetary exploration a level of capability representing an essential aspect of scientific methodology: an iterative process of observing, hypothesizing, testing, and synthesizing. Activities ideally suited to humans include those requiring the techniques of intensive field study and tasks requiring complex, physical articulation combined with expert knowledge and the ability to adapt to new situations. Humans conducting scientific observations on planetary surfaces can perform their work with an inherent flexibility not easily equaled by the more cumbersome and delay-ridden methods of remote control, especially at significant radio-de-

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Scientific Opportunities in the Human Exploration of Space lay distances (for example, at Mars). Assessment of complex natural systems makes excellent use of the human capability for serendipitous discovery and response. This human advantage is, for the time being, taken to pertain also to the activities of machines manipulated remotely by humans in near-real-time (that is, in a relatively local control loop with a short time delay). Robots have several obvious advantages. They are inherently expendable and thus should be used in situations in which the risk to humans is excessive or for which there is no clear advantage to using humans. Robots excel at performing repetitive, tedious tasks that are amenable to programming and that do not need or take advantage of unique human capabilities. Lastly, robots can have a duty cycle that is uninterrupted by the need to rest, sleep, or perform the mundane tasks that devour so much time in the everyday life of humans. RELATIVE LIMITATIONS Although humans offer specific advantages in the exploration of planetary surfaces, they have their limitations as well. Because of the harsh environments of the Moon and Mars and the amount of challenging physical work involved, safety considerations will always constrain the amount of time available for people to explore and perform scientific tasks. Humans working in spacesuits will always have less mobility and flexibility than humans working on Earth, despite anticipated improvements in spacesuits. In addition, scientific activities are not the only things people will be doing during human exploration missions. Routine maintenance of the habitat and other equipment is likely to occupy a significant fraction of the astronauts' time (as has become apparent for space station activities). Because of the broad range of scientific investigations proposed for human exploration, the crew (like robots) will not be expert in all relevant activities, although every attempt should be made to select crews that are highly qualified scientifically. Lastly, as was demonstrated in the Chernobyl nuclear accident, the potential for rapid human reaction in response to a local stimulus or observation has a concomitant potential for rapidly introducing errors. Robots likewise have limitations. The creation of nearly autonomous machines with humanlike cognitive abilities continues to elude the robotic research community and may well do so for a considerable time into the future. At the moment, robots are capable of only simple manipulation; techniques for human-quality dexterity have yet to be demonstrated. Given current capabilities, robots require considerable human control and interaction to accomplish most scientific tasks. Their capabilities are appropriate for simple reconnaissance or prescribed activities in which no major difficulties are encountered. Whether their capabilities will remain at this level

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Scientific Opportunities in the Human Exploration of Space will depend on advances in robotic technology prior to the initiation of a program of human exploration. Lastly, even though robots are inherently expendable relative to humans, their cost can be sufficiently large that they ought not be exposed to excessive risk. This limitation can be overcome to the degree that inexpensive robots are developed. THE OPTIMAL MIX OF HUMANS AND ROBOTS As a result of its deliberations, CHEX is convinced that the humans-versus-robots controversy is outmoded. The space program has perpetuated this antiquated either/or dichotomy for too long. Examining various aspects of exploration in terrestrial situations clearly shows the proper approach to be a mix. Considerable experience has been gained in assessing the relative capabilities of humans and robots operating in hostile environments for the location, development, and operation of underwater oil and gas fields. Divers are used primarily to perform tasks beyond the manipulative capability of robots. Robots are used, increasingly, to perform programmable repair tasks and to assess the physical state of systems. Similarly, robots are increasingly used in the hazardous environments presented by nuclear accidents and hazardous waste cleanup. Clearly, safety and risk minimization are paramount determinants in terrestrial situations; no less should be acceptable in human space exploration. A particularly germane example of the mix of human and robotic activities is in undersea exploration. Even though their exact role is still actively debated,1 robots are routinely used in oceanographic surveys to scan the ocean floor, emplace sensors, and collect samples. Even when human presence is desired, scientists do not usually study the deep ocean bottom in diving suits (read “spacesuits”) but, rather, in pressurized submersibles using teleoperated manipulators and/or robotic devices to probe and acquire samples. The analogy to potential lunar and martian exploration by humans and robots is clear: a synergistic mix based on safety, efficiency, and cost-effectiveness must be the goal. Given the relative strengths and weaknesses of humans and robots, CHEX envisages that their relative roles in a Moon/Mars program will evolve as knowledge increases and as technological capabilities advance. The initial phases, largely an extension of current space science and involving such activities as global orbital reconnaissance and the deployment of geophysical and meteorological networks, will be conducted exclusively by robots controlled from Earth or operating with varying degrees of autonomy. Further technical developments are needed in both robotics and operational capabilities (e.g., life support systems and exploration tools) to permit humans to survive and function effectively on planetary surfaces. These will

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Scientific Opportunities in the Human Exploration of Space lead to a subsequent phase consisting first of a mix of advanced robotic missions, such as those designed to return samples from Mars to Earth for analysis, and, eventually, the first human expeditions. CHEX envisions further evolution into advanced exploration performed by a synergistic mix of humans and sophisticated robots. Such a mix could, for example, include human operation on Mars supported by robots teleoperated in near-real-time by astronauts on, or in orbit around, Mars. One might think that an important issue bearing on the relative contributions of humans and robots in a Moon/Mars program would be cost-effectiveness. Ideally, the relative mix of humans and robots used for achieving a particular scientific goal would be based on cost-effectiveness. The concept of cost-effectiveness is, however, difficult to adhere to in a human exploration program, because even though it is axiomatic that robotic missions would cost less than those involving humans, the basic decision to proceed with human exploration is not rooted in science. In that light, CHEX recognizes that at any given time opportunity plays a significant role in prioritizing scientific projects and selecting means of implementation. Rather than dwell on cost-effectiveness, a more realistic principle, stated in the first CHEX report, is that, “Robotic options should be used until they provide enough information to . . . define a set of scientifically important tasks that can be well performed by humans in situ. . . . It cannot be demanded that these tasks be best and most cost-effectively performed by humans.”2 Subsequently, a mix of robots and humans should be used to optimize performance from both a scientific and a safety point of view. SCIENCE PRECURSOR MISSIONS Much information about the Moon and Mars has been collected by the Ranger, Surveyor, Lunar Orbiter, Luna, Apollo, Mariner, and Viking missions. However, an orderly series of future robotic missions will be required for collection of data relevant to human safety, for site selection, and for the effective identification and development of enabled scientific opportunities. Such a series of robotic missions would include many that would be a normal complement of an ongoing robotic planetary science program. For the Moon, several robotic missions are desirable, especially for site selection. A high-resolution global chemical and mineralogical survey of the Moon will allow a much more complete understanding of the variety of lunar geologic features, their origin, and their evolution. Such a survey will also allow for extrapolation of Apollo and Luna data and is needed for targeting more detailed local investigation. Robotic sample returns will greatly aid in further refining site selection and planning scientific investigations. Moreover, a global geophysical network, deployed by landers, will

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Scientific Opportunities in the Human Exploration of Space greatly increase our ability to weave the characteristics of the interior into an understanding of the surface evolution and the origin of the Moon.3 The pioneering observations performed by the Mariner and Viking missions to Mars were to have been extended by Mars Observer. This remote sensing orbiter mission was designed to characterize martian global geochemistry and the general circulation of the atmosphere. Its high-resolution imaging capabilities, important for geological studies, would also have been useful for selecting future landing sites and planning surface operations. The failure of Mars Observer in August 1993 is therefore a major setback to the scientific exploration of Mars, and the accomplishment of its objectives remains a high scientific priority. Assuming that a recovery program leads to the accomplishment of some or all of the Mars Observer objectives, a next step in the robotic exploration of Mars should be in situ robotic investigations of its geophysical and meteorological properties. Seismic activity should be explored for its intrinsic scientific value and to define more refined experiments that humans would emplace. Meteorological measurements are required to characterize the atmospheric boundary layer through which the key exchanges of energy, volatiles, and dust occur. The Viking landers made measurements at only two sites and had no capability to measure such important properties as water vapor concentration or to follow up on the discovery of chemical reactivity of the surface material.4 To take best advantage of human capabilities in scientific exploration, it will be desirable, some argue essential, to return reconnaissance samples from Mars prior to human exploration. Such sample return missions must deal with the obvious issues associated with planetary quarantine (both forward- and back-contamination).5 Returned samples will also address potential toxicity issues associated with the highly oxidizing properties of martian soil. This problem may also be tackled by in situ chemical analysis on robotic missions. Possibly more important, precursor sample returns will lead to a major increase in our knowledge of martian processes and history. This will permit a more informed choice of the landing sites for human missions and the types of investigations to be conducted during surface exploration. The Space Studies Board has recommended that “the next major phase of Mars exploration for the United States involve detailed in situ investigations of the surface of Mars and the return to Earth for laboratory analysis of selected martian surface samples. ”6 Stepping-stone missions, or “waypoints” in the language of the Synthesis Group's report, may provide significant scientific return and at the same time help to develop the technological capabilities required to get humans to Mars.7 For example, possible waypoints are human exploration of a near-Earth asteroid or the martian moons Phobos and Deimos.8, 9, 10 An

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Scientific Opportunities in the Human Exploration of Space asteroid mission could be used to test a Mars transfer vehicle and provide useful operational experience in deep space. TECHNOLOGY TO OPTIMIZE THE SCIENTIFIC RETURN CHEX recognizes that a program of human exploration would present an opportunity for major advances in our understanding of the Moon and Mars. To realize that potential, high-quality science must be an integral part of the exploration. The optimal strategy for accomplishing the associated science over the next several decades cannot be developed yet because of the uncertain prospects for advances in robotic systems and artificial intelligence. Major improvements in the human-machine interface of the type needed for the scientific activities discussed below require a focused program dedicated to the challenge of extending human capabilities in hostile environments by developing remote control techniques. A Moon/Mars program cannot rely totally on the development of robotics for terrestrial use. Robotic systems developed, for example, to replace a human welder on an assembly line will not be adequate to function as an extension of humans engaged in field work or maintaining complex instruments on the Moon or Mars. Special features not currently found in industrial robots, such as high-resolution stereoscopic vision and multispectral imaging, would most likely be required to conduct robotically assisted geological field work.11, 12 Coincident with the development of suitable robotics, one must address their effective use. For example, what and how much information should be transmitted to the human operator, and how large a time delay in the human-machine control loop can be tolerated? The extent to which a human exploration program is able to drive the development of more capable robotic systems over the next several decades, coupled with improved spacesuits (and development of mobile pressurized environments with teleoperations capability enabling humans to perform field work without the encumbrances of a spacesuit), will contribute to determining the optimal mix of humans and machines. Developments in robotics for use in hostile terrestrial environments (deep-sea exploration and activities in “hot” nuclear environments are examples already cited above) will be of great value. The biomedical research enabled by human exploration will also demand certain technological developments. Prime among these is the need to develop sophisticated, compact diagnostic equipment (some with telemetering capability) to perform essential studies on the responses of the crew and other living organisms to prolonged exposure to the environment of the spacecraft. Such equipment might also serve an important health and safety role in the event of accident or illness in the crew.

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Scientific Opportunities in the Human Exploration of Space The call for technology development could appear obvious and gratuitous; it might be expected that such would occur as a normal consequence of a well-structured plan for both scientific and human exploration. That has not, generally, happened. Study after study, several specifically dealing with the issue,13, 14 has urged greatly increased (by a factor of three) funding and more focused technology development by NASA and a more effective methodology for using existing and future funding. That not much progress has been made can be attributed to a combination of many factors, not all of which are under NASA's control: bureaucratic inertia, organizational conflicts, persistence of irrelevant technologies, low priority relative to near-term flight programs, inadequate justification of the need, lack of an appropriate requirement for an approved program, and political fear of enabling future programs. This combination of somewhat disconnected reasons begs for top-level, determined attention inside and outside of NASA. Without such attention, the committee is pessimistic that the United States will enjoy in the future the leadership in human and robotic space exploration that it has demonstrated in the past. REFERENCES 1. See, for example, Paul J. Fox and Craig E. Dorman, “Alvin and Deep Ocean Research” (letter), Science, 261, July 2, 1993. 2. Space Studies Board, Scientific Prerequisites for the Human Exploration of Space, National Academy Press, Washington, D.C., 1993, page 9. 3. Space Studies Board, 1990 Update to Strategy for the Exploration of the Inner Planets, National Academy Press, Washington, D.C., 1990, pages 18-19. 4. Space Studies Board, 1990 Update to Strategy for the Exploration of the Inner Planets, National Academy Press, Washington, D.C., 1990, pages 21-24. 5. Space Studies Board, Biological Contamination of Mars: Issues and Recommendations, National Academy Press, Washington, D.C., 1992. 6. Space Studies Board, International Cooperation for Mars Exploration and Sample Return, National Academy Press, Washington, D.C., 1990, pages 1, 3, and 25. 7. Synthesis Group, America at the Threshold, Report of the Synthesis Group on America's Space Exploration Initiative, U.S. Government Printing Office, Washington, D.C., 1991, page A-9. 8. NASA, Beyond the Earth's Boundaries: Human Exploration of the Solar System in the 21st Century . NASA, Washington, D.C., 1988, page 32. 9. Synthesis Group, America at the Threshold, Report of the Synthesis Group on America's Space Exploration Initiative, U.S. Government Printing Office, Washington, D.C., 1991, page A-37. 10. NASA, Science Exploration Opportunities for Manned Missions to the Moon, Mars, Phobos, and an Asteroid, NASA Office of Exploration Doc. No. Z-1.3-001 (also JPL Publication 89-29), NASA, Washington, D.C., 1989. 11. G. Jeffrey Taylor and Paul D. Spudis, “A Teleoperated Robotic Field Geologist,” Engineering, Construction, and Operations in Space II: Proceedings of Space '90, American Society of Civil Engineers, New York, 1990.

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Scientific Opportunities in the Human Exploration of Space 12. Paul D. Spudis and G. Jeffrey Taylor, “The Roles of Humans and Robots as Field Geologists on the Moon,” Lunar Bases and Space Activities of the 21st Century, 2nd Symposium, LPI Contribution 652, Lunar and Planetary Institute, Houston, Texas, 1990. 13. Aeronautics and Space Engineering Board, Committee on Advanced Space Technology, , Space Technology to Meet Future Needs, National Academy Press, Washington, D.C., 1987. 14. Space Studies Board, Aeronautics and Space Engineering Board, Committee on Space Science Technology Planning,, Improving NASA's Technology for Space Science, National Academy Press, Washington, D.C., 1993.