SAN MARINO, Calif. – NASA has cast a web of sensors over portions of the Huntington Botanical Gardens in the first field trial of a wireless network of instruments that could be used in the search for life on other planets.
For now, the sensor web’s dozen individual pods are stuck – literally – in the world of plants, not planets.
NASA scientists plopped the pods, each packaged in a plastic sandwich container, in different greenhouses here on May 18.

The Jet Propulsion Lab's Kevin Delin holds one of the sensor pods deployed at the Huntington Gardens.
Since then, the far-flung sensors have collected synchronized data on moisture, temperature, sunlight, humidity and oxygen levels every five minutes. The solar-powered stations then regularly shuttle the data among themselves, eventually "hopping" it back to a mother, or primary, pod connected to a laptop computer.
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"The instrument isn’t the individual pod, it’s the whole collection of them," said Kevin Delin, leader of the sensor web project at NASA’s Jet Propulsion Laboratory (JPL).
Networks on Mars?
Eventually, NASA hopes to pepper Mars with networks based on similar platforms, perhaps armed with sensors to sniff out minute amounts of methane produced by subsurface microbial life. Other networks could be stretched across Jupiter’s moon Europa, where they could chart the movement of the ice floes paving the icy satellite.

A closeup of the sensor pods deployed at the Huntington Gardens.
"The sensor web allows you to make measurements on a large scale, like in remote sensing, but with the sensitivity of in situ instruments," Delin said.
The idea of making simultaneous scientific observations on a distributed basis is a popular one within NASA. The agency’s failed twin Deep Space 2 microprobes, lost with the Mars Polar Lander last December, were a first stab at deploying the concept on the Red Planet.
"It’s a way of surveying a very large area very cheaply," Delin said.
Rotor-like wings
NASA has no immediate plans to send another such network to Mars or Europa. But if and when it does, it may deploy the constituent elements from orbit. Tiny versions of the pods, no larger than a gumball, could use rotor-like wings to flutter to the ground like maple seeds.
Or a rover could scatter the pods as it made its way across the surface of Mars, creating a path of electronic "breadcrumbs" that it could zap data along. Even if the rover were out of range, the data could hopscotch back to a lander for relay to Earth.
On Earth, the pods could be used as smart fire detectors, or to measure changes in the microclimates of complex gardens like the Huntington, located just south of Pasadena, California. The Huntington includes gardens that mimic the climes of everything from bone-dry deserts to lush tropics.

With advances in electronics, the pods shrink to gumball size.
James Folsom, director of the gardens at the Huntington, formally known as the Huntington Library, Art Collections and Botanical Gardens, called the sensor web a valuable addition to the world of ecology.
"They are going to add to our arsenal of quantifying devices to understand the world around us," Folsom said.
Tracking thermal changes
The field trial is not the first time JPL and the Huntington have collaborated.
Last summer, JPL loaned an infrared camera to the gardens so it could track any thermal changes in a blooming Amorphophallus titanum flower. The camera showed that the giant Sumatran plant – often known as the "corpse flower" for its rotting meat-like stench – heated up before blooming.
On Thursday, Huntington nursery manager Theresa Trunnelle showed off two rare corpse flower seedlings – complete with their own high-tech NASA sensor pod to measure soil temperature.