A balloon with ‘ears’
Hot air ascent tests equipment that listens for ‘infrasound’
Three hours. That’s how long the unmanned, solar-powered hot air balloon “Jon Magnus” was airborne after climbing to 21,000 feet — far short of the 100,000 feet necessary to beat the current altitude record for that type of balloon.
Nevertheless, it was still pretty impressive for a craft created by an Albuquerque geophysicist, who makes balloons for a hobby, for less than $100.
The balloon launched from Albuquerque’s Balloon Fiesta Park about 7:30 a.m. Wednesday and landed between Clines Corners and Santa Rosa. An onboard satellite tracker indicates that it stopped moving around 10:40 a.m., said Daniel Bowman, who constructed the balloon.
The four-story-tall balloon envelope was put together from thin plastic and coated on the inside with “biochar,” a black carbon material
made from plant waste. The black material absorbs heat from the sun, causing the balloon to continue filling with hot air as it rises through the atmosphere, Bowman said.
The balloon, made from commonly available materials, was assembled at the Anderson-Abruzzo Albuquerque International Balloon Museum.
Under ideal conditions, the balloon might have remained aloft until the sun began setting, causing the air in the envelope to cool and the balloon to descend.
“I think it might have been too turbulent, so my best guess is that we had a rupture and the balloon came down slowly,” Bowman said.
What’s more important, however, was how well an acoustic listening device called the Raspberry Boom was working, which was the focus of the ballooning effort — although setting a new altitude record would have been nice, too, said Bowman.
“All the equipment is safe and accounted for and we’ll be looking to see how well the Boom performed and what (sounds) it may have picked up.”
The Raspberry Boom is designed to listen to “infrasound,” sounds carried by pressure changes in the atmosphere but are below the range of human hearing, explained Mike Hotchkiss, marketing manager of Raspberry Shake, which makes and sells the Boom.
Raspberry Shake, a company based in Panama, builds sophisticated, but affordable citizen science Earth monitoring equipment. These sounds, or frequencies, can travel for thousands of miles, and can come from a wide variety of sources: Lightning, tornadoes, volcanic eruptions, explosions, meteors, rocket launches, the Aurora Borealis, nuclear tests, wind farms, sonic booms, waterfalls, wind colliding into mountains, avalanches, landslides, fireworks, even some animal calls.
“Each of those sounds has a different vibration and registers as a different signature on the software,” making it possible to tell the different sounds apart, Hotchkiss said.
Mass production of the Raspberry Boom, expected to sell for $600 or less, will be made possible via an ongoing Kickstarter campaign.
A Kickstarter campaign that ended 18 months ago raised enough money for the company to mass produce the Raspberry Shake Earth Motion Seismograph. The personal home-use seismograph is capable of measuring a wide range of ground movements triggered by rumbling traffic, fracking, quarry explosions, local tremors and larger earthquakes halfway around the world, said company director Branden Christenson.
The device, which sells for about $375, has thus far been purchased by about 600 people around the world. The seismographs are linked together, creating a worldwide online network that continuously sends data and updates an interactive map that can be retrieved via a phone app, Christenson said.
The intention with the Raspberry Boom device is to also link those together in a worldwide network.
“We are creating the largest citizen-powered network in the world,” said Hotchkiss. “We’ve already had interest from various geological institutes, and it’s likely that governments will want access to it also — though we’re not sure how we feel about that.”