Spiderbots Dropped into Super Volcano cauldron: Mount St Helens

(Image: USGS/Dan Dzurisin)
A helicopter drops off an earlier version of a spiderbot in the crater of Mount St Helens in 2006

A squadron of 'spiderbots' inside Mount St Helens is the first network of volcano sensors that can automatically communicate with each other and with satellites, rather than sending data to a base station first.

Since the system can route data around any sensors that break and can simply be dropped into volcanoes, it is more robust and easier to deploy than current sensor systems, which must be carefully set up by hand.

Similar networked robots could one day be used to study geological activity elsewhere in the solar system, say scientists from NASA's Jet Propulsion Laboratory, which helped develop and monitor the robots.


Fifteen spiderbots, so-named because of the three spindly arms protruding from their suitcase-sized steel bodies, were lowered from a helicopter to spots inside the crater and around the rim of Mount St Helens, an active volcano in the US state of Washington, in July.

Each has a seismometer for detecting earthquakes, an infrared sensor to detect heat from volcanic explosions, a sensor to detect ash clouds, and a global positioning system to sense the ground bulging and pinpoint the exact location of seismic activity.


Once in place, the bots reached out to each other to form what is known as a mesh network. "It's similar to the internet," says Steve Chien, the principal scientist for autonomous systems at JPL. "You just lay them out, and they figure out the best way to route the data."

Self-healing
Other robotic volcano-monitoring systems exist, most notably around Mount Erebus in Antarctica. But they require permanent sensors to be buried in the ground or drilled into rock, which can take days of dangerous human labour.


The spiderbots are flexible and inexpensive enough that they can be set down almost anywhere. "You can imagine just dropping these out of a helicopter, and they'll just land like spikes in the ground and do their thing," Chien says.

The spider web's unique networking capabilities also give it a distinct advantage over other monitoring systems. The network is self-healing – if one node dies, the others automatically route data around it.


The scientists added this innovation after several early models were boiled, crushed or knocked over in the volcano's 2004 eruption. They also made the hardware more resilient. "These are much more rugged," says Rick LaHusen of the US Geological Survey. "They can take an impact and keep on working."