Geologists call them "spiders" -- pods that are small and tough enough to reach places no man dares, like the vent on the volcano.
"Nobody really wants to go in there and dig in a new instrument. It's too much risk," said Rick LaHusen with the U.S. Geological Survey.
Each stainless steel box is a self-contained volcano laboratory that sends instant data for immediate analysis.
GPS units detect movements down to the centimeter. Lead plates pick up even tiny foot taps. And pressure gauges sense small explosions.
On Tuesday a dozen spiders were hooked to a helicopter and put in place on North America's most active volcano.
The flight into the crater was the culmination of a 2-year, $2 million partnership between the U.S. geological survey, Washington State University and NASA. The space agency isn't so much interested in the volcanoes as the spiders, including how they communicate with each other and satellites in space.
"They share a network. They automatically find a network and a route out somewhere to the observatory," LaHusen said.
By talking to each other, the spiders also determine which information is most important and which spider has priority.
"You don't have to go and reconfigure each one. You don't have to hike up the volcano and do this, or fly up the volcano and start tinkering with it," said Sharon Kader of NASA's Jet Propulsion Laboratory.
After blanketing Mount St. Helens, the next step is putting a series of $3,000 spiders on other volcanoes.
With some fine-tuning, geologists say spiders could become the cheapest, safest way to predict an eruption.