After months of trials to hone their technique, a team of Stanford students has set a world record for the longest high-altitude flight with a latex balloon.
The achievement by the Stanford Student Space Initiative (SSI), a student-led campus group that focuses on space and aerospace research, shows small teams with low budgets how to perform serious high-altitude atmospheric research.
High-altitude balloons — those that fly 15 to 35 kilometers above Earth’s surface — are one way that researchers can deploy scientific instruments for aerial missions such as gathering atmospheric data, observing the sky or testing space systems.
The record-setting flight, eighth in a series of efforts that began months earlier, was launched on June 15 outside Modesto, California. The flew for 70 hours and 10 minutes, crossing into and out of Canadian airspace, and eventually landed off the Atlantic coast of the United States. The Stanford flight beat the previous world record of 57 hours and 2 minutes, as recorded by the Amateur Radio High Altitude Ballooning organization.
The helium-filled latex balloon had a gas venting valve and ballast dispenser, allowing it to adjust altitude autonomously or via remote control. Costing under $1,000, the so-called ValBal balloon provides an affordable approach to aerial research.
“Our system presents a high-altitude platform for consumers who want to fly in the upper atmosphere and control systems at a relatively low price,” said Aria Tedjarati (Class of 2017), a rising senior in electrical engineering who is the ValBal project manager and software lead.
Assistant professor of aeronautics and astronautics Marco Pavone, faculty advisor for the SSI balloon team, provided advice and safety oversight, but the 30 students were responsible for design, building and mission control. Among other things, students had to continuously monitor the balloons’ behavior and coordinate with the Federal Aviation Administration (FAA) to ensure that the balloons didn’t interfere with airplane flight paths.
“One of the essential skills in engineering is to be able to interface with other people and other skill sets,” Pavone said. “For me, this represents a tremendous learning and teaching experience.”
Although latex balloons are inexpensive, they deteriorate under ultraviolet light in the atmosphere, giving even successful missions a limited lifespan. The record-setting flight of June 15 followed five prior ValBal vehicles and seven prior flights, where the previous longest duration was 23 hours to Canada.
“It’s really fulfilling to see all of this time that we put into it actually pay off and make a payload that can go up into the sky and fly for longer than anything anybody else can make – or at least with comparable cost,” said Kai Marshland (Class of 2019), who worked on the mission control software.
Not long after their record-setting flight, the SSI balloon team launched a new ValBal into the night sky (see video) on July 12. This version incorporated more readable software. Assembling it took about a day, instead of weeks. Less about endurance than making future missions more practical, this flight lasted 47 hours and 47 minutes before the balloon landed in New Mexico.
Andrey Sushko, a seasoned SSI member who graduated this June with bachelor’s degrees in physics and mathematics, was the balloon’s chief designer and said it had been a “very good opportunity” to work on student-led, hands-on group projects.
“We’re working based on our own knowledge: what people bring in and what people learn,” said Sushko, also known as the “balloon technical overlord.” “So it’s really the best environment to learn from other people how to get something done.”
Tedjarati, who will soon begin a co-terminal master’s degree in electrical engineering, valued his SSI projects. “The fact that I could [work on a project] myself with a group that allows me to take my own initiative is just something that I think is really amazing,” he said.
SSI’s balloon team plans to start flying scientific payloads on future flights and will continue to design electronics that are more modular and flexible. Students say they are currently seeking research ideas and collaborators. “The conditions at certain altitudes emulate conditions on certain places on the surface of Mars,” said Brandon Vabre (Class of 2019), a rising sophomore in mechanical engineering who joined SSI his freshman year. Vabre urged “anyone else that can make use of the atmospheric conditions up there to come to us.”
In addition to the balloon project, SSI’s 120 members include teams focused on rockets, satellites, space policy, operations and biology in space.