A group of computer engineering students finished a yearlong project on May 30 after launching a high-altitude balloon from Moses Lake, Washington.
Pumped up with 250 cubic feet of helium and carrying two scientific payloads, the latex balloon traveled an estimated 80,000 feet into the air — ascending briefly into the stratosphere — before eventually bursting and landing about 60 miles east of the launch site.
All along the way, the students and supporting faculty members managed to track the balloon’s position in semi-real-time, thanks to an on-board electronic device designed and built by fourth-year students Jason Dempsey, Jimi Huard, Tyler McGrew, and recent graduate Johnny Sim.
Using a radio tracking system known as Automatic Packet Reporting System (APRS), the payload device was able to broadcast its global positioning data via built-in antennae to a series of ham radio towers on the ground.
“The large advantage to APRS is that it gets repeated throughout the ham radio network,” Dempsey said. “So it’s like this big mesh network where there are radio stations that are constantly repeating out all these transmitted signals to everywhere else. And they eventually get put on the Internet. So you can track it in pseudo-real-time — kind of like a ‘Where is my package now?’ thing on the Internet.”
As the balloon traveled eastward, students used a free web site (www.openaprs.net) to plot the payload’s journey onto a Google map. Driving primarily east on Interstate 90 from their starting location at Grant County International Airport in Moses Lake, a payload recovery team tracked the device’s last broadcast to a dirt field about 12 miles northeast of the town of Ritzville.
“It just went surprisingly well,” Huard said. “We drove to the end of this road. The road ended at a farm. Then we walked straight for about a mile. And the last reported location — it was maybe 100 feet from there.”
Prior to the Saturday launch, the students had tested their device extensively both in and outside the lab. In addition to driving with the APRS system around Redmond, the team conducted a series of test and tethered balloon launches using earlier prototypes.
The students also conducted temperature chamber testing at the University of Washington, ensuring that the final device would be able to continue functioning in the sub-freezing temperatures of the upper atmosphere — at altitudes far above those of commercial jetliners.
The balloon also carried a second payload device for measuring and broadcasting data relating to the ambient light level. That device was designed by first-year student Keith Tompkins.
One of three faculty advisors on the project, Jeremy Thomas, Ph.D., said the Saturday launch gave students a useful opportunity to test one of their engineering projects in an authentic environment — part of a process sometimes referred to as life-cycle testing.
“We want to get more of that into the curriculum,” Thomas said. “It doesn’t always have to be a balloon, but some kind of end point where you have to really demonstrate that [your project is] going to work outside the lab, which is actually really hard to do.”
You can watch a video of the balloon launch and recovery, including footage recorded by an external camera attached to the main payload package.
Balloon Launch and Recovery Video (9 min.)
Aerial Footage Video (4 min.)
Christopher Theriault and Lukas P. Van Ginneken, Ph.D., also served as faculty advisors on the project.