NASA technology sensed the heartbeats of four people trapped in rubble days after a huge 7.8-magnitude earthquake struck Nepal on April 25, saving the lives of the four men.

The new prototype technology — called FINDER (short for Finding Individuals for Disaster and Emergency Response) — uses microwave-radar technology to find people trapped under debris by sensing and locating their heartbeats. Two suitcase-sized FINDER prototypes developed by NASA and the Department of Homeland Security’s (DHS) Science and Technology Directorate were brought to Nepal to help with rescue efforts on April 29.

"The true test of any technology is how well it works in a real-life operational setting," DHS under secretary for science and technology Reginald Brothers said in a statement. "Of course, no one wants disasters to occur, but tools like this are designed to help when our worst nightmares do happen. I am proud that we were able to provide the tools to help rescue these four men."

NASA's damage proxy map is used to help relief workers assess which areas need aid in Nepal. Image: NASA/JPL-Caltech/ASI/Google Earth

The men were trapped for days under debris in the village of Chautara, according to the press release. The FINDER devices detected the heartbeats of two men trapped beneath about 10 feet of rubble in one location, and another two survivors of the earthquake trapped in another. Rescue workers were then able to go in and pull the people out of the collapsed buildings.

Microwave radar technology can actually help users tell the difference between a human heartbeat and the heartbeats of other living things, the DHS has said. One big benefit to FINDER is that people trapped in rubble don’t need to be conscious in order to be saved, because the technology finds beating hearts.

According to NASA, the device has detected people buried under up to 30 feet of rubble, hidden behind 20 feet of solid concrete, and from a distance of 100 feet across an open space. The technology can peg the location of trapped individuals to within about five feet of their location, depending on the type of rubble they are trapped in, NASA says.

Developed with private industry partners, the device is moving into a commercial enterprise phase, and will soon be available for purchase by rescue agencies and organizations around the world.

Areas affected by the earthquake have become something of a test-bed for emerging technologies in the wake of this disaster.

The company Skycatch is using its drones to map aid efforts in Nepal. Their drones are able to provide high-resolution imagery that can be used to photograph areas to learn more about the damage caused by the earthquake. Other groups are also flying drones to help relief efforts in the hard-hit areas of the country.

The company DigitalGlobe open-sourced its satellite imagery of Nepal to users, asking them to help map damage caused by the earthquake.

FINDER isn’t NASA’s only contribution to the relief effort. The space agency is also using satellite data collected by probes to put together maps of potentially vulnerable areas and places that were most damaged from the quake.