Pairing drones with weather balloons creates a robust data collection system

Sandia National Laboratories unmanned aerial system expert Dave Novick examines an octocopter prior to the first joint balloon-UAS test in May. Photo credit: Randy Montoya

Drones are reaching new heights and distant lands, according to researchers at Sandia National Laboratories. Together for the first time, a tethered balloon and an unmanned aerial system (UAS) were able to determine Arctic atmospheric temperatures with better location control than previous attempts.

Not only is this a win for climate scientists, who will better be able to collect precise weather data and create climate models, but being able to effectively operate drones in the arctic opens up new opportunities for national security options.

According to Jon Salton, a Sandia robotics manager, integrating the specialized operational and sensing needs required for Arctic research will transfer to a variety of national security needs.

Tethered balloons or weather balloons require helium and extensive set-up prep, which is why using a drone can be more effective and launch in more remote locations.

Most airports already collect atmospheric temperature profiles twice a day but switching to UASs with distributed temperature sensors would be better because they would be reusable and could fly more frequently, said Sandia atmospheric scientist Dari Dexheimer, who has been flying tethered balloons out of Sandia’s dedicated Arctic airspace on Oliktok Point, AK.

These 13-foot-tall balloons carry distributed temperature sensors to collect Arctic atmospheric temperature profiles. The test earlier this month was the first time Sandia has flown an octocopter in the sky above Oliktok Point.

“The UAS and the balloon really complement each other in that the UAS has a smaller flight time, but it’s much more spatially diverse. The tethered balloon can stay up for a long time, giving you a lot of data, but it’s not easily mobile,” said Dexheimer.

Pairing the two together has been beneficial as the balloon is blown by the wind, to the limits of the tether, and the drone can be directed to precise GPS coordinates.

Earlier this summer, the team tested the joint UAS-balloon setup at Sandia. They encountered some technical challenges that they were able to overcome including figuring out how to best secure and reel out the four-football-field long distributed temperature sensor cable while making sure it doesn’t get tangled in the UAS’s rotors.

They were also required to solve the logistics of operating a balloon and drone together at the same time. They successfully tethered the balloon downwind and the UAS stayed at least 100 feet away from it to avoid bumping into each other or tangling cables.

In addition to the temperature sensor, the tethered balloon carries special supercooled liquid water sensors to better understand mixed-phase clouds. The sensors are vibrating wires upon which supercooled liquid water can freeze. As the ice builds up, the vibration slows, and this tells researchers how much supercooled liquid water is present in that part of the cloud.

The researchers hope to add these supercooled liquid water sensors to a fixed-wing UAS and fly into the clouds.

“Our ability to run UASs as well as tethered balloon operations in the Arctic, and our ability to combine those measurements and computer modeling in innovative ways, allows us to really put the Oliktok facility to use for the national security and science communities,” said Lori Parrott, manager of atmospheric sciences at Sandia.