High-altitude scientific balloon and PUEO now soaring over Antarctica

A NASA scientific balloon carrying a next-generation space science instrument was successfully launched over Antarctica, continuing a legacy of discovery that began at University of Hawaiʻi at Mānoa.

The mission — known as Payload for Ultrahigh Energy Observations, or PUEO — lifted off Dec. 20, 2025, from NASA’s launch facility near McMurdo Station. The balloon reached an altitude of about 120,000 feet and is now drifting high above the Antarctic ice while collecting data.

You can track the balloon in real time online.

Payload for Ultrahigh Energy Observations is designed to study neutrinos — tiny particles that travel through space at extremely high energies.

When these particles strike the thick Antarctic ice, they create brief radio signals. The balloon-mounted instrument listens from its vantage point far above the surface for those signals, using the ice below as a natural detector.

Scientists hope to learn more about powerful events in the universe, such as black hole formation and collisions between dense stars, by tracking these signals.

The mission also includes two additional balloons that send test signals to help researchers confirm the instrument is working properly.

Payload for Ultrahigh Energy Observations is expected to remain airborne for several weeks, circling the continent as it gathers information.

“This mission shows how ideas that start in Hawaiʻi can grow through years of collaboration and dedication into discoveries that help answer some of the biggest questions about our universe,” said University of Hawaiʻi at Mānoa Department of Physics and Astronomy professor Peter Gorham in a release detailing the new research. “It reflects the creativity and persistence of our students, researchers and engineers, and it points to a future where [University of Hawaiʻi] research continues to play a meaningful role in advancing science worldwide.”

Payload for Ultrahigh Energy Observations builds on earlier work led by University of Hawaiʻi researchers through the Antarctic Impulsive Transient Antenna.

The earlier project completed four balloon flights between 2006 and 2016, helping open a new way of studying high-energy particles using radio signals detected over Antarctica. It also recorded unusual particle events scientists are still working to understand.

Payload for Ultrahigh Energy Observations aims to expand on those discoveries and clarify unanswered questions from the earlier missions through improved sensitivity and updated technology.

This is the second high-altitude scientific balloon launched from Antarctica this season with major University of Hawaiʻi involvement.

A separate scientific balloon carried the General AntiParticle Spectrometer experiment into the sky Dec. 15, 2025, to search for rare cosmic antimatter linked to dark matter.

The missions together highlight the university’s growing role in NASA-led balloon research, using Antarctica’s unique environment to study some of the most basic questions about the universe.

Payload for Ultrahigh Energy Observations is led by University of Chicago professor Abigail Vieregg.