Published: April 5, 2024

Zach Ulibarri posing with instruments

Congratulations to Dr. Zach Ulibarri, who was named a 2024 51 Pegasi b Fellow by the Heising-Simons Foundation. The 51 Pegasi b Fellowship provides postdoctoral scientists with the opportunity to conduct theoretical, observational, and experimental research in planetary astronomy.

Dr. Ulibarri earned his PhD in physics from CU Boulder in Spring 2022. As part of his graduate work, he performed experiments at the Colorado Dust Accelerator, which contributed to the development of the Surface Dust Analyzer (SUDA) instrument,  set to launch on NASA’s Europa Clipper in October 2024.

“Most people don't really think about dust, but it’s incredibly important in space,” Ulibarri said. “You can use it to sample the chemistry of planetary objects without landing. You can fly by and scoop up those dust grains without the expense and difficulty of landing on the object.”

Dr. Ulibarri’s experiments determined the speed limit for the breakup of complex organic molecules undergoing hypervelocity impacts, which instruments such as SUDA rely on as they attempt to detect such molecules from orbit.

“Let’s say you’re trying to fly by a planetary object, and it has some sign of life on it,” he said. “If the spacecraft smacks into this thing at five kilometers a second, does it break up that organic biomolecule and destroy the information you’re trying to get? That’s what I studied, and the answer is around seven kilometers a second.”

Zach is now a Postdoctoral Researcher in mechanical and aerospace engineering at Cornell University, where he is working on adapting an instrument called the electrospray ionization mass spectrometer (ESI-MS) for use in space. This instrument currently studies biomolecules on Earth, but during his new fellowship, Dr. Ulibarri hopes to adapt its functionality to work outside of Earth’s parameters, so that delicate extraterrestrial biomolecules can be studied in orbit or on lander spacecraft.

“Electrospray ionization mass spectrometers are fantastically useful instruments and they’re very good at studying organic biomolecules,” he said. “The trouble is they’re massive cubes as tall as I am. They weigh a ton, maybe two. They cost a couple hundred thousand dollars and they’re incredibly complex. The challenge is to put one of these on a spacecraft and have it survive launch and get all the way to a planetary object without breaking.”

Established in 2017, the Heising-Simons Foundation 51 Pegasi b Fellowship is named for the first exoplanet discovered orbiting a Sun-like star. In the growing field of planetary astronomy, scientists study objects both within and beyond our solar system, bridging planetary science and astronomy. From improving our understanding of planetary system formation and evolution, to advancing new technologies for detecting other worlds, 51 Pegasi b Fellows make a unique contribution to the field.

In addition to monetary support of up to $430,000, 51 Pegasi b Fellows will receive networking and mentorship opportunities to help advance their work in this crucial field of astrophysical science.

The Heising-Simons Foundation is a family foundation based in Los Altos and San Francisco, California. The Foundation works with its many partners to advance sustainable solutions in climate and clean energy, enable groundbreaking research in science, enhance the education of our youngest learners, and support human rights for all people. Learn more at