Mars work by UC Berkeley’s George Pimentel recognized with national historic landmark

George Pimentel teaching at UC Berkeley where he was on the chemistry faculty for four decades. Photo: UC Berkeley

On a recent Monday afternoon at UC Berkeley, cheers and hollers from a graduation ceremony could be heard on the east side of campus. A quieter, but no less significant, ceremony was taking place simultaneously on a plaza next to Pimentel Hall, the distinctive red circular lecture hall inside of which a revolving stage allows multiple professors to teach, clean up, and set up chemistry demonstrations at the same time.

The hall is named after George Pimentel, a chemistry professor who was on the faculty at Cal for four decades. It is largely thanks to Pimentel, along with Kenneth Herr, who worked in his lab, that we know as much as we do today about Mars and its make-up, including the fact that there was once water on its surface. In the late 1960s the pair designed and built the Mars Infrared Spectrometer (IRS), two of which were carried aboard NASA spacecraft Mariner 6 and 7 which set off in 1969 to examine the red planet.

On May 15, the importance of Pimentel’s work was recognized as the Mars IRS was officially designated an American Chemical Society National Historic Chemical Landmark. The honor was bestowed 50 years after the first model of the instrument was assembled at the College of Chemistry; it was the result of a suggestion from local ACS member Attila Pavlath, who sought the help of George Pimentel’s widow, Jeanne, as well as former College of Chemistry Dean Richard Mathies and others.

Dedication ceremony at UC Berkeley on May 15, 2017 — Jeanne Pimentel (left) and Susan Arbuckle, who was George Pimentel’s secretary when he was working on the Mars Infrared Spectrometer which led to the American Chemical Society National Historic Chemical Landmark designation. Photo: Tracey Taylor

George Pimentel died in 1989 at the age of 67, but Jeanne — who met the scientist six months after the NASA mission and says he was still “aglow with Mars” — has stayed connected to the chemistry department and last week expressed her appreciation for the honor.


“This is a perfect place to put the landmark, because it ties together the two aspects of science that George was passionate about, research and teaching,” she told Berkeleyside. “The IRS landmark recognizes his research, and this building, Pimentel Hall, reflects his dedication to teaching — he taught freshman chemistry here right up to the year he died.”

ACS established the landmark program in 1992 and has recognized achievements such as the creation of Bakelite, the world’s first synthetic plastic; the discovery and development of penicillin; and the work of historical figures such as Joseph Priestley, George Washington Carver and Rachel Carson. There are fewer than 100 landmarks, and this is the second one awarded to UC Berkeley — the other came in 1997 and was for Gilman Hall, specifically Room 307, where Glenn T. Seaborg and his coworkers identified plutonium as a new element on Feb. 23, 1941.

George Pimentel (right) and Ken Herr with the Mars Infrared Spectrometer that they designed and built with a team in the College of Chemistry and the Space Sciences Lab at UC Berkeley. Photo: UC Berkeley

There was an element of the renegade scientist to Pimentel and his team who were responsible for developing the first instruments — and remain among the few — to fly on a NASA mission that were built at a university rather than at NASA facilities or aerospace companies. The young chemists loved their work and loved having fun, and they clashed with what they saw as the stuffy formality and excessive bureaucracy of NASA’s Jet Propulsion Laboratory in Pasadena with which they were partnering.

“The crew from Berkeley did not get on with the Jet Propulsion Lab,” confirmed Jeanne Pimentel at the dedication ceremony, which was attended by Berkeley Mayor Jesse Arreguín, himself a Cal alum. “But they had imagination and creativity and they got the job done and they had courage in taking risks to get the finest instrument made.”

Speaking at last week’s dedication ceremony, Paul Forney, one of the scientists on the Pimentel team recalled pulling all-nighters working on the project, and the fun the crew had when they travelled to Cape Canaveral to see the launch of the twin Mariner spaceships. Although they had been told to stay several miles away from the launch pad, the gang crept to a spot just 500 yards away. They then watched as scores of armadillos and lizards ran past them just as the rockets blasted off.


And George Pimentel’s daughter, Jan Coonrod, herself a science teacher, spoke about her father’s fondness for levity and how he built a cardboard rocket of the Mariner and set it up in the family’s backyard.

A bronze plaque designating the Mars Infrared Spectrometer as an ACS National Historic Chemical Landmark was unveiled at the May 15 ceremony, and a version of the Mars IRS is on view inside Pimentel Hall. It is accompanied by a display of historical materials and photographs tracing the efforts of the Pimentel team to create and launch the spectrometer.

Dedication ceremony at Pimentel Hall on the UC Berkeley campus on May 15, 2017. Photo: Tracey Taylor
Dedication ceremony at Pimentel Hall on the UC Berkeley campus on May 15, 2017. Photo: Tracey Taylor
A bronze plaque designating the Mars IRS as an ACS National Historic Chemical Landmark is unveiled outside Pimentel Hall on the UC Berkeley campus on May 15, 2017. Photo: Tracey Taylor
A bronze plaque designating the Mars IRS as an ACS National Historic Chemical Landmark is unveiled outside Pimentel Hall on the UC Berkeley campus on May 15, 2017. Photo: Tracey Taylor