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John Bluck                                                                                          June 15, 2004

NASA Ames Research Center, Moffett Field, Calif.

Phone: 650/604-5026 or 604-9000


Rosanne Spector

Stanford University Medical Center, Stanford, Calif.

Phone: 650/725-5374

Release: 04-56AR      


A lightweight, portable device developed by NASA scientists is enabling physicians to monitor the health and safety of explorers in remote locations on Earth. It may eventually be used in space to monitor astronauts during space travel.

The wireless LifeGuard system watched over the vital signs of several expedition members who sampled soils and water from the world's highest alpine lake, nearly 20,000 feet up the Licancabur volcano, on the border between Chile and Bolivia, late last year.

"Having the team wearing these LifeGuard systems added an element of safety in this extreme environment," said expedition leader Nathalie Cabrol of NASA's Ames Research Center in California's Silicon Valley. The system allows real-time monitoring of vital parameters such as heart rate, blood pressure, electrocardiogram (EKG), breathing rate and temperature. It also can measure human movements in three dimensions.

The LifeGuard units sent real-time vital signs from subjects at the volcano to scientists at NASA Ames by satellite. This demonstrated the monitor's potential to work in an extreme environment. The test demonstrated the enhanced ability for doctors to practice telemedicine over long distances on Earth or potentially in space.

"More recently, we did experiments aboard NASA's KC-135 aircraft that flies big, rollercoaster-like maneuvers to create short periods of weightlessness," said Dr. Gregory Kovacs of Stanford University, Stanford, Calif.

"During the KC-135 flights, we explored the body's vital signs' response to changing gravitational forces, and we transmitted the wireless data from the subject to another location in the plane. The experiments were quite successful," Kovacs added.

"The data logger part of the system that collects data from body sensors is about the size of your palm and weighs about 166 grams (six ounces)," said Carsten Mundt, an engineer who is developing LifeGuard at NASA Ames. "The sensors we use are quite easy to apply and comfortable to wear," Mundt said.

The LifeGuard's button sensors stick to the skin to take EKG and breathing rate. The device uses an arm cuff to measure blood pressure. The data logger connects to a sensor clipped or wrapped on an index finger to measure oxygen in the blood and pulse rate. The system's sensors connect to the LifeGuard by wires. LifeGuard's data logger has a transmitter that radios collected data to a base station computer. The data logger has sensors that measure astronaut movements in three dimensions.

"LifeGuard also could be used by physicians on Earth, since the system could be put on a patient very quickly and transmit vital signs during transfer to the hospital," Mundt said. "When the patient comes in, the doctor would already know the patient's status," Mundt added.

 "The system can be worn by firefighters and hazardous material workers to monitor their health during activities," Mundt said. "It could even be worn by patients at home," he added. Home uses could include diagnosing sleep disorders, heart disease or unsteady gait in the elderly.

The NASA team working on the LifeGuard system has been developing physiological monitors for the past decade. The Astrobionics team at NASA began work on LifeGuard in October 2002, and is collaborating with the National Center for Space Biological Technologies at Stanford University. The research is in support of the NASA Office of Exploration Systems and the Vision for Space Exploration. For more information about LifeGuard on the Internet, visit:

For information about NASA and agency programs on the Internet, visit:

Publication size images related to LifeGuard are on the World Wide Web at:



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