18 August 2009

Volcano “spiders”

Posted by Jessica Ball

Most of us hate the thought of an infestation, but in the case of volcano-monitoring ‘spiders’, it’s a safe way to gather information about active volcanoes. A number of recent articles have been talking about a new NASA program to drop instrument-loaded tripods on Mount St. Helens, putting monitoring equipment in areas that are dangerous for scientists to visit or just plain inaccessible. (See additional coverage on the Volcanism Blog, National Geographic News, and Geology News, and a photo of one of the new NASA instruments above.)

Many of you will remember “Spiderlegs” from the movie Dante’s Peak, which was a shining example of a waste of money – at least the way the scientists in the movie were using it. Trying to get a robot to climb over piles of shifting, jagged rocks is pretty hard, and if it keeps breaking while you’re trying to use it, it’s not worth the effort of dragging the thing to the top of a mountain. (I also suspect that NASA truly would not have appreciated Spiderlegs being kicked around – literally – during the repair process.)

As it turns out, however malfunctional their creation was on film, the moviemakers were working from reality – both NASA and the USGS have been using various ‘spider’ incarnations to monitor volcanoes for more than a decade. NASA tested two robots (Dante I and II, in 1992 and 1994, respectively) in volcanic craters which were real life versions of the Spiderlegs that showed up in the 1996 movie. Both were tethered robots which descended into volcanic craters – Mt. Erebus in Antarctica for Dante I, and Mt. Spur for Dante II (seen at left) – with varying success. According to the 1994 article on NASA’s website, the robots were a joint effort on the part of NASA, Carnegie Mellon, and the Alaska Volcano Observatory. The article also says that

“NASA’s goals with this project were to test and demonstrate robot exploration, communications and computer technologies which may be needed for future space exploration missions. Carnegie Mellon’s interests include extending the results of this demonstration to other more practical Earth-based applications, including additional volcanic exploration, mining and mine safety operations, large-scale agricultural deployment and hazardous environment operations for industrial and municipal organizations. The Alaskan Volcano Observatory’s goal is to obtain information on the chemical and temperature properties of the crater floor, and a higher resolution video survey map of the crater interior.”

The first deployment of a ‘spider’ on Mount St. Helens was in 2004 (see more images at the CVO’s website). These spiders were a nonmobile but portable bundle of instruments – GPS, seismic, etc. – that can’t be installed permanently because of the terrain or conditions. They’re relatively expendable, which more expensive instruments and scientists are not, and they function without human oversight.

The first helicopter deployment of an early spider in October 2004 (CVO Photo Archives).

A “tilt-leg” spider on the north face of the Mount St. Helens lava dome in January 2005. (CVO Photo Archives)

The early spiders only consisted of one or two instruments apiece, but new models have multiple sensors (and have spiffy software that can sort out what’s important enough to send on to scientists). According to NASA’s website,

A team of engineers, students, volcanologists and geologists put the system together. The team includes the U.S. Geological Survey’s Cascades Volcano Observatory staff, who designed and built the “spider” hardware; Washington State University in Vancouver, where the sensor network software was written; and NASA, which developed software to make the spiders able to detect events to trigger space observations by the EO-1 satellite.

All in all, exciting new stuff – and a big improvement from the poor ungainly contraption that Pierce Brosnan was trying to coax down a bouldery slope on an imaginary volcano.