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