“Out of This World” Space Stethoscope Valuable on Earth, Too

Space is serene, because no air means no sound. But inside the average spacecraft, with its whirring fans, humming computers and buzzing instruments, is about as raucous as a party filled with laughing, talking people.

“Imagine trying to get a clear stethoscope signal in an environment like that, where the ambient noise contaminates the faint heart signal. That is the problem we set out to solve,” said Elyse Edwards, a senior from Issaquah, Wash., who teamed up on the project with fellow seniors Noah Dennis of New York City, and Shin Shin Cheng of Sibu, Sarawak, Malaysia.

The students worked under the guidance of James West, a Johns Hopkins research professor in electrical and computer engineering and co-inventor of the electret microphone technology developed for telephones and used today in almost 90 percent of the more than 2 billion microphones produced each year.

Together, they developed a stethoscope that uses both electronic and mechanical strategies to help the device’s internal microphone pick up sounds that are clear and discernable – even in the noisy spacecraft and even when the device is not placed perfectly correctly on the astronaut’s body.

“Considering that during long space missions, there is a pretty good chance an actual doctor won’t be on board, we thought it was important that the stethoscope did its job well, even when an amateur was the one using it,” Dennis said.

The project was developed during a two-semester mechanical engineering senior design course offered by the university’s Whiting School of Engineering. Teams of three or four undergraduates are each given a small budget to design and build a prototype requested by a sponsoring business or organization. This year’s results were unveiled recently at a showcase conducted shortly before the students were scheduled to graduate.

The device also includes many other performance-enhancing improvements, including low power consumption, rechargeable batteries, mechanical exclusion of ambient noise and a suction cup, so that it sticks firmly onto the patient’s chest, Cheng says.

Though developed for NASA’s use in outer space, this improved stethoscope could also be put to use here on Earth in combat situations, where ambient noise is abundant, and in developing countries where medical care conditions are a bit more primitive.

West also plans to use the device to record infants’ heart and lung sounds in developing countries as part of a project that will attempt to develop a stethoscope that knows how to identify the typical wheezing and crackling breath sounds associated with common diseases. This would allow on-site medics to help make preliminary automated diagnoses.