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Katherine K. Martin
Media Relations Office

June 4, 2007
RELEASE : 07-014
NASA Tests Metabolic Sensors In Undersea Mission
Cleveland--A team of scientists at NASA's Glenn Research Center developed and tested an innovative device that measures the key quantities necessary to evaluate crew physical fitness levels during long-duration missions.

The Portable Unit for Metabolic Analysis (PUMA) was shipped to the Florida Keys National Marine Sanctuary and tested by the crew of NASA's Extreme Environment Mission Operations 12 Project (NEEMO 12) in the underwater Aquarius habitat. Between May 7 and 18, Aquarius, 60 feet below the surface, was home to six aquanauts who tested various space medicine concepts, robotic telesurgery and moon-walking techniques. Aquarius is owned by the National Oceanic and Atmospheric Administration and operated by the University of North Carolina at Wilmington.

Twice during the mission, the NEEMO crew wore PUMA for twenty minutes to determine resting metabolic rate. This was PUMA's first use in an environment different from Earth's standard atmosphere. Pressure in Aquarius was 2.5 times higher than is experienced at sea level and that difference may cause changes in human metabolic performance.

"Being able to operate PUMA in an extreme environment was a great opportunity," said Daniel Dietrich, principal investigator for PUMA. "PUMA technology could be extremely valuable for exploration missions, where it will be measuring the metabolic functions of astronauts while working in low gravity environments."

NASA monitors the physical fitness of astronauts during long missions, where the absence of gravity can potentially weaken muscles and impact the crew's physical well-being. PUMA's portability makes it an excellent candidate for use in microgravity, or in other settings with space constraints. The device goes beyond the capability of hardware currently available onboard the International Space Station, because it is battery operated and self-contained, featuring an electronics box that fits into a small, wearable pack. PUMA also expands the functions of hardware currently used to quantify astronauts' metabolic functions. A more detailed and accurate picture of the astronauts' physical fitness can be obtained by measuring the pressure, temperature, flow rate, carbon dioxide and oxygen partial pressure of the inhaled-exhaled breath stream, than by measuring the heart rate alone.

Dietrich adds, "In addition to use in the space environment, PUMA's technology is being considered for use right here on Earth in determining the caloric requirements of daily living activities to develop nutrition and weight loss programs; to assess the nutritional needs of critical care patients; to determine the impact of certain foods on metabolic rate; and to quantify the field training of athletes to design effective training programs."

Work on PUMA was made possible through funding provided by the John Glenn Biomedical Engineering Consortium. This work is part of the NASA's Human Research Program, which is dedicated to providing human health countermeasures, knowledge, technologies and tools to enable safe, reliable and productive human space exploration.

For more information about PUMA, visit:

For more information on the NEEMO mission, visit:


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