Caltech Mourns the Passing of Carl Grillmair (1959–2026)

Carl Grillmair, an astronomer at Caltech's IPAC science and data center for astronomy and planetary science, passed away suddenly on February 16, 2026. He was 67 years old.

Grillmair's science interests spanned many topics, such as exoplanets and stellar streams, which are remnants from ancient collisions between our Milky Way and other galaxies. He discovered dozens of these streams, with many named by him. In 2007, in one of his most impactful findings, he was lead author on a publication that "captured for the first time enough light from planets outside our solar system, known as exoplanets, to identify molecules in their atmospheres," according to a press release about the work.

Grillmair was born in 1959 in Calgary, Alberta, Canada, to parents Leo and Elfi Grillmair. He had two younger siblings, Elizabeth (Liesl), born in 1960, and Walter, born in 1961, who passed away in 1981. Interested in astronomy since his youth, he received an undergraduate degree in astrophysics from the University of Calgary in 1983, followed by a master's degree from the University of Victoria in 1986, and a PhD from the Australian National University in 1993.

In 1997, Grillmair joined IPAC, initially serving as a member of NASA's Spitzer Space Telescope Infrared Spectrograph (IRS) and Infrared Array Camera (IRAC) instrument support teams, and as deputy lead of the IRS team.

"He was part of IPAC's bedrock for many years, and his passing impacts all of us across IPAC," says Tom Greene, IPAC's executive director and a research professor of astronomy.

"It was always a pleasure to experience Carl's creativity in doing science. His methods on exoplanets and galactic structure studies were truly detective work, allowing him to infer events that took place many billions of years ago," says Sergio Fajardo-Acosta, a fellow astronomer at IPAC.

Over the course of nearly 30 years at IPAC, Grillmair worked on numerous projects, including as a quality assurance scientist and pipeline operator at the NEOWISE Science Data Center—NEOWISE was a NASA mission that used a space telescope to hunt for asteroids and comets in our solar system, including those that could impact Earth. He also served as the instrument characterization specialist for NASA's upcoming Near-Earth Object Surveyor (NEO Surveyor) mission.

Recently, he began a project to test new instrumentation at Caltech's Palomar Observatory to monitor for meteor impacts on the Moon's surface during an upcoming lunar eclipse. "It is a really exciting project, and I know he was looking forward to seeing what we could learn about the near-space environment from that," says Joe Masiero, NEO Surveyor lead scientist at IPAC, where he was Grillmair's colleague and collaborator.

Grillmair was the recipient of the 2011 NASA Exceptional Scientific Achievement Medal and numerous NASA Group Achievement Awards, and he was named to the MacLean's magazine honor roll in 2006 as one of "Thirty-Nine Canadians Who Make the World a Better Place to Live."

Over his research career, Grillmair was awarded more than 400 hours of Hubble and Spitzer Space Telescope time as a principal investigator (PI) and more than 2,700 hours as a co-PI, and published 147 peer-reviewed papers, with three in preparation at the time of his passing.

In his personal life, Grillmair was an avid pilot, flying small aircraft and gliders that he owned and maintained at his home; he would cheerfully accept requests to fly with him. Friends and associates recall that he loved the outdoors, driving tractors, and doing repairs and other construction work on his house, where he also kept a small observatory with several telescopes.

Fajardo-Acosta has dedicated IPAC's weekly series of science talks known as The Next Seven Minutes to Grillmair's memory, citing his unending love of science and his passion to enrich the life of IPAC.

He is survived by his wife, Louise.