Report of the Workshop on Biology-based Technology to Enhance Human Well-being and Function in Extended Space Exploration (1998)

Biological systems are regenerative, energy and size efficient, and adaptable to changing environments. As humans venture further into space and spend longer periods of time there, these attributes may provide the basis for technologies that can sustain life in deep space and on other planets.

This concept was explored at the Workshop on Biology-based Technology to Enhance the Human Presence in Extended Space Exploration, held on October 21-22, 1997, by the Space Studies Board (SSB) of the National Research Council at the Center for Advanced Space Studies in Houston, Texas. The objective was to identify areas in biology-based technology research that appear to hold special promise for carrying biological science into technology directly applicable to space exploration.

Workshop participants sought to identify how biological concepts and principles might contribute to enabling technologies for long-duration missions involving the actual presence of humans (as opposed to robots only) at exploration sites on other planets, such as Mars (see Chapter 1). In the 2010 to 2020 time frame and beyond, NASA proposes to carry out international human missions to planetary bodies such as Mars (a mission of at least 600 days) with no crew rotation or resupply available. Such a mission is beyond today's technical capabilities. Advances are needed in a variety of technical areas to reduce risk, equipment weight, power requirements, and costs as well as to increase reliability.

The workshop's two discussion sessions focused on biology-based research areas with a potential for (1) enhancing human well-being in space exploration and (2) enhancing human presence and function in space exploration. Because the workshop was intended as an initial effort and not a detailed scientific investigation, participants dealt with the discussion topics in a somewhat conceptual manner and did not attempt to assess their merits.

Based on discussions in the two sessions and on their quantitative judgments, participants identified six topics that seem promising enough in the near term to warrant further examination in follow-on workshops: closed-loop aquaculture systems as a model for advanced life support (ALS) water processing and waste management systems; biosensors for detecting pollutants and pathogens in air and water; biomaterials for spacecraft and habitats; space suit design incorporating biological concepts; use of magnetoencephalography to monitor astronauts ' cognitive states; and synergistic human-robot systems. Also identified in each session were

additional areas in which R&D advances by NASA or others may benefit the space program either in the near-term or over the longer term.

The concepts discussed in sessions 1 and 2 are described in Chapter 2 and Chapter 3, respectively. Chapter 4 touches briefly on workshop participants' observations regarding points for considerations in any follow-on activities—including the importance of defining specific technical requirements for long-duration human exploration of space and the usefulness of tracking developments in fields other than aeronautics and space science that may contribute to the application of biology-based systems and principles in Human Exploration and Development of Space (HEDS) Enterprise missions.

Session 1 participants sought to identify biological concepts and principles that might be further explored to address needs related to regenerative advanced life (ALS) support systems, spacecraft and habitats, and the health of humans and useful biological organisms. A central theme was the value of reducing, reusing, recycling, and recovering materials so as to reduce size, mass, and power requirements (and thus cost) as well as increase reliability for long-term human exploration of space. Session 1 participants identified three topics that seem promising for exploration in follow-on workshops, as well as two research areas that might offer NASA short-term payoffs and two that might offer longer-term payoffs.

Closed-loop Aquaculture Systems as a Model for ALS Water Processing and Waste Management Systems. Provision of clean water is a basic requirement for extended space exploration missions. A workshop on current technologies in the maturing field of closed-loop aquaculture and innovative fermentation processes used in waste treatment might assist in the development of highly efficient closed-loop regenerative ALS systems for extended space missions.

Biosensors for Detecting Pollutants and Pathogens in Air and Water. To maintain human health and comfort as well as functioning plant and microbial populations, rapid and reliable detection and monitoring systems are needed to ensure that air and water in spacecraft and in habitats do not contain disease-causing pathogens or discomfort-causing levels of pollutants. Potential applications of biosensors could be explored in a workshop that would also have to define the research required to identify which microorganisms and pollutants should be detected on spacecraft and habitats and to establish sensitivity requirements relevant to NASA's needs. The use of biosensors in the skin of planetary habitats that could alert the crew to radiation levels

and/or level of radiation-induced damage could also be addressed as part of this follow-on workshop.

Biomaterials for Spacecraft and Habitats. Biomaterials and biologically inspired materials might incorporate capabilities ranging from self-diagnosis and self-repair of certain system components to protection of astronauts and other biological organisms from the effects of radiation. Furthermore, such materials could also help make missions to other planets possible by virtue of their being lightweight and renewable, offering opportunities to reduce transportation cost and mass. These and other potential attributes as well as trade-offs in labor, space, and energy should be examined in a focused workshop before specific biomaterials are used in space applications.

Cultivation of Algae as Food. Algae and cyanobacteria are used as nutritional supplements on Earth and might be cultivated for that purpose on spacecraft, as well as for waste treatment, CO₂ recycling, and O₂ generation. In addition to identifying edible species that could be grown in the space environment, it may also be worth exploring the genetic engineering of algae and/or cyanobacteria to enhance their value and palatability as food, or the development of suitable food processing methods to either remove or degrade undesirable components (such as nucleic acids). Because cyanobacteria are more easily cultured and genetically engineered than eukaryotic algae or higher plants, they may hold greater promise in the short run for use in air recycling, wastewater treatment, and food production. The significant base of information on algae and cyanobacteria needs to be reexamined to identify their potential for use in such applications.

Development of Plants with Enhanced Disease Resistance. The types of diseases likely to occur in space horticulture must be identified so that plants resistant to specific diseases can be developed. Research is also needed to enable identification and management of the relevant disease-causing organisms.

Enzymatic Catalysts for Housekeeping. Humidity control is probably key to preventing overgrowth of microorganisms, which can also become resistant to the biocides used to wipe down bulkheads. When cleaning is necessary, enzymes (e.g., proteases, lipases) can be used as alternatives to chemical cleaning agents, an approach that has emerged for industrial cleaning applications. Enzymes, which are naturally occurring proteins, can be designed to target the compounds that enable microorganisms to adhere to surfaces. Furthermore, enzymes are highly suitable for spaceflight because they are lightweight, biodegradable, and have a long shelf life. However, some enzymes may cause allergies. Research is needed to examine the feasibility of using enzymes for housekeeping in spacecraft and planetary habitats, and to evaluate risks of exposing crew members to these potentially potent allergens.

Genetic Engineering of Plants. Plants, a fundamental biological system, will be essential to human well-being in long-duration space exploration. Plants can be used not only as food but also as sources of useful materials and chemicals and for the recycling of carbon dioxide and other inorganic and organic wastes. To meet defined requirements for spaceflight, plants might be engineered, for example, to produce miniature roots or leaves, grow under low-light conditions, exhibit increased resistance to disease or radiation, and produce structural materials such as biodegradable plastics or specific nutrients needed by humans.

Radiation Protection and Monitoring. Certain plants and microorganisms have effective DNA-repair mechanisms that confer some measure of radiation resistance or tolerance. Research aimed at understanding such mechanisms might provide a basis for transferring these capabilities to plants and organisms cultivated on spacecraft. It may also be possible to design a biological dosimeter for radiation monitoring through the use of specific microorganisms or designed DNA integrated into biochips for monitoring purposes. The applicability of advanced biological dosimeters for space exploration could be addressed as part of the workshop on biosensors suggested above.

Session 2 participants sought to identify biological concepts and principles that might enhance human function in four areas: perception, manipulation and locomotion, cognition, and systems and computation. The group discussions reflected a number of themes, including similarities between deep space and the deep ocean that suggest a potential for transferring diving technologies and concepts to the space program; the merits of biological concepts as models for processes that are inherently simple and evolutionary, as opposed to complex and excessively mechanical; and the need to strike an appropriate balance between the tasks assigned to machines versus those assigned to humans. The group identified three topics that seem promising enough in the short term to be addressed at follow-on workshops.

Space Suit Design Incorporating Biological Concepts. As part of the effort to design lightweight space suits suitable for use on Mars, biological concepts and principles could be applied to enhance astronauts' comfort and function. A future workshop could explore, for example, the application of biomechanical concepts such as 40-degree-angle wrist settings to provide maximum dexterity and grip, biomolecular materials modeled on strong yet dexterous sharkskin, technologies such as actuators and microelectrical mechanical systems (MEMS) that could assist with movement or self-repair, external sensors that produce haptic and other sensory feedback to the astronaut, and galvanic stimulation to provide cues about spatial orientation in microgravity.

Use of Magnetoencephalography to Monitor Astronauts' Cognitive States. Physiological monitoring of brain waves could provide confidential biofeedback on astronauts' cognitive states for the purpose of enhancing functional effectiveness and promoting relaxation. Magnetoencephalography, which is based on the use of superconducting quantum interference devices (SQUIDs) to detect very small magnetic fields, offers a number of advantages, including rapid response and ease of use. A SQUID cryogenic cap or helmet for recording brain waves may be particularly appropriate in the space environment, where temperatures are theoretically cold enough to make the SQUIDs superconducting. A future workshop could explore the benefits and feasibility of designing such a system.

Synergistic Human-Robot Systems. A future workshop could explore the design of synergistic human-robot systems that would meet needs for system reliability and configurability, effective human-machine collaboration, improved situational awareness, and optimal decision making. Three biology-based concepts seem particularly promising: (1) collaborative multirobot systems modeled on the task sharing of the insect kingdom. Advantages include rapid adaptation to the loss of individual robots, robust communication among all robotic or biological elements, system reconfigurability, and the capability to deploy specialized individuals. (2) Robotics systems that exhibit emergent system behavior mediated by emotion and anxiety, as well as a learning process augmented by emotion. Such systems would “think” more like humans, whose decision-making and problem-solving abilities are improved by access to their emotions. (3) Interfaces that enable human comprehension of system data without information overload, and the communication of human affect and intentions to robots.

Artificial Vision Systems. Technologies being actively investigated in many sectors offer the possibility of enhancing human vision and providing new modalities, such as over-the-horizon sight. However, existing devices tend to be bulky, primitive, and, in most cases, far less sensitive, precise, or adaptive than their biological counterparts. The state of the art needs to be improved. Of particular interest is using very large-scale integration (VLSI) and MEMS technology to integrate sensing, processing, and possibly display elements into small, lightweight, low-power units. Biological principles and biology-inspired designs could provide critical guidance in such efforts. For instance, visual computational sensors or artificial retinas that provide spatio-temporal processing at the place of sensing could enable task-oriented, rapidly adaptable processing of visual information.

Exercise Based on Biological Concepts. As an alternative or supplement to the treadmill currently used for exercise during spaceflight, it might be useful to explore an exercise concept that mimics the activities of an embryo during its time in the womb. A “bungee suit” with elastic properties might be designed that would enable gymnastics regimens that could maintain or restore an astronaut's physical state.

Adaptation to Different Gravitational States. Astronauts' adaptation to microgravity and subsequent readaptation to Earth's gravity might be accelerated by understanding and manipulating the fragile transition between the two states. Evidence from everyday life and biomedical research—including a rapid increase in understanding of the central nervous system and its plasticity—points to an inherent biological capability for dual adaptation. A combination of pharmacological intervention and appropriate training and exercise might effectively prepare astronauts for adaptation to alternating gravitational states.

Software for Emotion-Mediated Learning. In humans, emotional states mediate decision making and learning. Software for robotics systems could be designed to exhibit emergent system behavior mediated by emotion and anxiety, and a learning process augmented by emotion. Such systems might meet needs for software reliability and configurability, effective human-machine collaboration, improved situational awareness, and optimal decision making.

“Principal Investigator (PI) in a Box.” Given the complexity and new challenges associated with long-term human exploration of space, astronauts might benefit from having instant access to a database of the accumulated experience of previous astronauts. The database could support dynamic mission planning and execution strategies and improved problem solving and could be self-organizing to respond to immediate needs. Biology-based concepts could also be applied to the presentation of data. For example, algorithms based on the survival instinct might present data on the most-life-threatening situation first.