Rising to the challenge of Senior Design with an altitude-controlled balloon


Eleanor Wyllie

Cameron and Christopher launch the Illini Voyager
Cameron and Christopher launch the Illini Voyager

On the evening of May 11, a volunteer firefighter in rural West Virginia received an unusual call out. He drove an hour to an unused service road and climbed a tree to retrieve a balloon. Not just any balloon – this marked the end of the Illini Voyager’s inaugural 16.5-hour journey and the culmination of months of work for ECE senior Cameron Jones and sophomore Christopher Xu.

The National Weather Service launches weather balloons twice a day, every day, at almost 100 sites across the US. Our forecast relies on data from these daily launches. However, most weather balloons are one-use, unable to control their altitude or direction of travel. They rise straight up and pop, only recording the data from the column of air above their launch site. The majority are never recovered after launch. 

As well as being more sustainable, a weather balloon with longer endurance and altitude control can collect interesting data, such as detecting high-energy particles over the Antarctic. Balloons with longer flight times can tell us more about space weather, including the impact of solar storms on our electronics, telecommunications or grids. 

Illini Voyager logo
Illini Voyager logo

Chris and Cameron’s Senior Design project, the “Illini Voyager,” is a 1500g latex weather balloon attached to a payload that uses an automated venting and ballast system to control its altitude. The electronics that collect data and control the system are housed in an insulated foam box to protect them from the extreme cold of the upper atmosphere. This meant the balloon system needed thermal, mechanical and electrical components, as well as firmware and software (it had a code base of 2000-3000 lines). Inspired by a similar weather balloon project by students at Stanford, they chose the project as a synthesis of their expertise: Cameron’s work on space hardware and Chris’ skills as a roboticist. However, both students discovered that there was a lot to learn.

One of their biggest challenges was testing the equipment on campus to see how well it would operate at very high altitudes and ultra-low temperatures (the lowest temperature they measured during the actual flight was -68º C or -90.4ºF). “The fun part for me was finding interesting and creative ways to test all the pieces,” Chris commented. They used an ultra-low temperature freezer at the Chemical and Life Sciences Building, a vacuum chamber, and even simulated ascents and descents using the Electrical and Computer Engineering Building: the team ran up the stairs holding the system to test how it responded to different ‘altitudes’ (the actual flight averaged over 50,000 feet).

Testing the equipment in a vacuum chamber (left) and ‘altitude’ testing in the ECE Building elevators (right)
Testing the equipment in a vacuum chamber (left) and 'altitude' testing in the ECE Building (right)

Before the flight, Chris and Cameron described their expectations as “very, very low” and “wildly varying.” If it had worked perfectly, it would have flown to the Atlantic Ocean, but they were equally expecting that it might pop immediatelly after launch. Overall, the team is happy with its initial 16.5-hour voyage.

It was a challenge building everything from scratch within the time constraints, and both students emphasized the support from their professors, classmates and community, from the Open Lab at ECE to The Grainger College of Engineering and the broader U of I campus. The ECE Facilities team were particularly supportive, helping them move a large helium tank to the Aeronomy Field Station for the launch.

Chris emphasized the collaborative nature of this project and the impact of the university environment: “I wouldn’t have been able to do this by myself. I learned so much from being surrounded by people doing similar things.” 

“Project-based learning is really important,” Cameron commented. “Taking on a project and learning everything you need to succeed in it is extremely powerful.”

As for their next steps, sophomore Chris plans to develop a realistic robotic squirrel, which he hopes to perfect by graduation. Cameron is graduating this year and starting work at the SpaceX avionics team in Boca Chica, Texas. We look forward to seeing what they both achieve next.

The inaugural flight of the Illini Voyager. Top image shows the route, graph shows altitude over time.
The inaugural flight of the Illini Voyager. Top image shows the route, graph shows altitude over time. During the flight, Cameron and Christopher were in constant contact with the FAA and local ATC centers to make sure the balloon was legal and wouldn't interfere with air traffic.