This summer, a team of University of Chicago undergraduates is preparing to launch a custom-built atmospheric particle collection instrument aboard a NASA high-altitude balloon.
Unlike standard weather balloons, this specialized balloon will take the students’ instrument, PASCAL, to the mid-stratosphere, targeting a region of the upper atmosphere so rarely sampled that the last comparable mission took place more than 35 years ago.
PASCAL, or Particle Acquisition from Stratospheric Conditions for Analysis in Laboratory, is a mission designed, tested, and operated entirely by undergraduates in the UChicago Space Program. Led by third-year undergraduate Mason McCormack, who identified the scientific gap, the team of 13 undergraduates secured faculty support and won a NASA grant within 3 months.
Conceived in October 2025 and set to launch in late August 2026, PASCAL will collect and characterize atmospheric particles at an altitude of 37 kilometers (122,000 feet), well above where commercial or even research aircraft can reach.
Their instrument will fly aboard NASA’s High Altitude Student Platform (HASP) on a large zero-pressure balloon that carries multiple student experiments on a single flight from NASA’s Columbia Scientific Balloon Facility in Fort Sumner, New Mexico.
While most high-altitude balloon experiments rise to a maximum height of roughly 30 kilometers for only a few hours, HASP reaches 7 kilometers higher, into the near-space conditions of the mid-stratosphere, and sustains that altitude for around 13 hours. This extended float is possible because the NASA science balloon holds 40 million cubic feet of helium, so vast that a football stadium could fit inside of it when inflated.
“This is an altitude that most missions can’t reach and not for nearly as long,” said McCormack. “So, getting our payload on this platform is an incredible opportunity.”
At 37 kilometers, the upper atmosphere (i.e., the mid-stratosphere) contains a mix of particles whose origins are largely unknown but are theorized to range from the natural to the human-made: dust shed by asteroids, debris from spacecraft burning up on reentry, rocket fuel trapped in the atmosphere, sulfate aerosols from volcanic eruptions, and soot from wildfires. Understanding the size, composition, and distribution of these particles matters for climate science and atmospheric modeling, but the data is scarce.
“Right now, there’s a very poor understanding of these particles because there just aren’t that many missions that go to this height and hardware fails easily in the extreme conditions,” McCormack said. “There are all these particles that are important for our understanding of the chemistry and physics of the stratosphere and how it’s changing, but we don’t really understand their population or distribution.”
PASCAL weighs roughly 14.5 kilograms and is built around two cascade impactors called Mini-MOUDIs, which sort incoming air into size fractions and deposit particles onto collection stages. One impactor actively samples air throughout the float, when the balloon is at its highest altitude. A second serves as passive control against contamination. A secondary instrument, the Portable Optical Particle Spectrometer (POPS), on loan from the National Oceanic and Atmospheric Administration (NOAA), monitors particle size distributions during ascent and descent.
After sample recovery in mid-September, the team will analyze collected particles using highly specialized lab equipment at UChicago and the Field Museum. Scanning electron microscopy and energy dispersive X-ray spectroscopy will characterize size, particle numbers, shape, and elemental composition, while thermal desorption mass spectrometry will investigate the presence of chemical compounds that evaporate easily (e.g., methane, benzene).
A key goal for the PASCAL team is to compare how useful each method is, helping establish best practices for future missions. The data from the analysis will help to inform atmospheric models of the stratosphere and will be available for immediate use in chemical reaction experiments that simulate atmospheric interactions at NASA’s Jet Propulsion Laboratory.
The team is designing PASCAL to be low-cost, lightweight, and open-source so that other universities and research groups can replicate or build on it, creating a long-term database to monitor changes in the mid-stratosphere.
“It was challenging to understand what’s really going on in this region of the atmosphere,” McCormack said. “Having a platform for other universities to use would be very valuable towards increasing humanity’s understanding of the mid-stratosphere.”
PASCAL receives financial support from the University of Chicago’s Climate Systems Engineering initiative (CSEi), and that support has been essential to getting the mission off the ground in a short timeline.
“We are incredibly grateful for the support of our faculty mentor Professor Elisabeth Moyer, as well as Professor David Keith and CSEi. This project is possible because of the trust that they have put in us,” said McCormack.
Building on this support, the team aims to have PASCAL serve as the foundation of a long term high-altitude balloon program.
“This is the first time that a UChicago undergrad team can conduct and fly an experiment on this scale,” McCormack said. “We want to establish a program so that over time, every year, we have a team of undergrads that are doing experiments on NASA science balloons and developing technical skills.”
Integration and testing at NASA’s Columbia Scientific Balloon Facility in Palestine, Texas, is scheduled for late July, ahead of the September 2nd launch from Fort Sumner, New Mexico.
“I’m excited about having something we’ve worked with, something we’ve touched, going that high and doing impactful science,” added team member Danielle Riekse. “I can’t wait for launch. It’s going to be awesome.”
PASCAL is the work of a 13-person undergraduate team spanning astrophysics, physics, molecular engineering, computer science, and economics. The project is advised by Elisabeth Moyer (Associate Professor, Geophysical Sciences), with additional faculty collaboration from Philipp Heck (Professor, Geophysical Sciences), David Keith (Professor, Geophysical Sciences and Founding Faculty Director, CSEi), Mingyi Wang (Assistant Professor, Geophysical Sciences), Steve Meyer (Professor Emeritus in Astronomy, Astrophysics, and Physics), and Dan Cziczo (incoming Professor, Geophysical Sciences).
The full 13-person PASCAL project team includes: Mason McCormack, Lawrence Li, Natalie Orrantia, Danielle Riekse, Ashley Ashiku, Seth Knights, Daniel Boscu, Vyshakh Thejaswi, Robert Pitu, Catherine Todd, Graydon Schulze-Kalt, Matthew Tsui, and Mohammad Hassan.
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