Balloons will surf wind currents to track wildfires [MIT Tech Review]

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This August, strange balloons will drift high above Colorado. These airy aircraft, launched from the back of a pickup truck, will be equipped with sensors that can measure heat on the ground, pinpointing new wildfire outbreaks from above. 

The company behind the balloons, called Urban Sky, also plans to use them to  understand conditions on the ground before fires start. Approximately 237,500 acres burn in Colorado annually, according to 2011–2020 data from the Rocky Mountain Area Coordination Center. The hope is that this new high-altitude tool might allow humans to manage—or at least understand—those blazes better.

“Wildfire is a natural part of ecosystems,” says Michael Falkowski, manager of the wildland fire programs at NASA. But climate change has proved to be an accelerant, rendering fires bigger, more intense, and more frequent. At the same time, more people are living closer to wild spaces, and the US’s history of fire suppression, which has crowded forests and left old and dead vegetation sitting around, is fanning the flames. 

To deal with modern fires, Falkowski says, researchers and fire agencies have to gather data before those fires start and after they’re done smoldering, not just as they’re burning. That makes it possible to understand the risks ahead of time and try to mitigate them, track ongoing blazes, and understand the threats fires pose to communities and the environment.

Before a fire takes hold, researchers can map vegetation and estimate how wet or dry it is. During a fire, they can map where and how hot the activity is. When it’s all over, they can assess the severity of the burn and track air quality.

COURTESY URBAN SKY

Still, the most acute phase is obviously the one when the fire is actually burning. In the heat of that moment, it can be hard to get a handle on when and where, exactly, the fire is taking hold. Satellites do some of that work, surveying large areas all at once. But the primary governmental satellites produce pictures with pixels around 300 meters across, and they can’t always get a super timely look at a given spot, since their view is limited by their orbit. 

Airplanes and helicopters can map a fire’s extent in more detail, but they’re expensive to operate and dangerous to fly. They have to coordinate with other aircraft and have smaller views, being closer to the ground. They’re also a limited resource. 

Urban Sky aims to combine the advantages of satellites and aircraft by using relatively inexpensive high-altitude balloons that can fly above the fray—out of the way of airspace restrictions, other aircraft, and the fire itself. The system doesn’t put a human pilot at risk and has an infrared sensor system called HotSpot that provides a sharp, real-time picture, with pixels 3.5 meters across. “We targeted that resolution with the goal of being able to see a single burning tree,” says Jared Leidich, chief technology officer at Urban Sky. “And so that would show up essentially as one pixel—one hot pixel.” The company has some competition: Others, like Aerostar and LUX Aerobot, also make balloons that can monitor wildfires.

The Urban Sky team has launched balloons in previous tests, but in August, the technology will monitor potential fires for an actual (unspecified) customer. Sending the balloon-lofted HotSpot up will be a surprisingly simple affair, thanks to the balloon’s relatively small size: While the company makes several sizes, the original is about as big as a van at launch, inflating to the size of a small garage once it’s aloft and surrounded by lower-pressure air. The Urban Sky team uses weather software to calculate where to launch a balloon so that it will drift over the fire at the right elevation. Then the team packs one up, along with compressed helium or hydrogen gas, and drives a truck out to that location. The balloon is hooked onto a mast jutting from the vehicle, filled up with the lighter-than-air molecules, and released. The whole process takes about 10 minutes. 

Once the balloon hits its cruising altitude, the HotSpot sensor turns on. Through satellite communication networks, an onboard processor sends real-time information about actual hot spots back to people on the ground. 

The balloons can hover over a fire for about 18 hours, using the whims of the atmosphere to stay in place. They fly near the top of the troposphere and the bottom of the next atmospheric layer: the stratosphere. “Those often have winds going in different directions,” explains Leidich. To move back and forth, the balloon simply has to go up or down. 

Urban Sky’s unnamed customer for its August deployment takes data on wind patterns and fuels (also known as trees, bushes, and grass) to try to understand the spots where fires are most likely to start and spread. It is interested in integrating Urban Sky’s on-the-ground (read: in-the-air) data on where fires actually do break out. “They want to add an extra step to the process where they actually scan the areas that are high risk,” says Leidich.

During the campaign, if officials identify or suspect a fire, Urban Sky can send out the truck. “We put a balloon up over the area to scan the area and say, ‘Yes, there is a fire. Here it is,’” says Leidich. 

COURTESY URBAN SKY

If they get yeses where they should and nos where there is nothing to see, the proof of concept could lead to wider adoption of the HotSpot system, perhaps offering a simple and timely way for other regions to get a handle on their own fires.

This year, Urban Sky also has a grant through NASA’s FireSense program, which aims to find innovative ways to learn about all three fire phases (before, during, and after). At the moment, the August campaign and the NASA program are the primary customers for Hot Spot, although the company also sells regularly updated aerial images of 12 cities in the western US.

“It’s kind of an interesting technology to be able to do this active fire detection and tracking from a high-altitude platform,” Falkowski says of Urban Sky’s balloons. 

With NASA’s support, the team is hoping to redesign the system for longer flights, build in a more robust communication system, and incorporate a sensor that captures blue, green, and near-infrared light, which would make it possible to understand those plant-based “fuels” better and assign risk scores to forests accordingly. Next year the team is planning to again hover over real fires, this time for NASA.

And there will always be fires to hover over. As there always have been, Falkowski points out. “Fire is not a bad thing,” he says. “These ecosystems evolved with fire. The problem is humans are getting too close to places that just need to burn.”

Sarah Scoles is a Colorado-based science journalist and the author, most recently, of the book Countdown: The Blinding Future of Nuclear Weapons.