Donald M. Hunten

1998 John Adam Fleming Medal Winner

Lunar and Planetary Laboratory, University of Arizona

Donald M. Hunten was awarded the John Adam Fleming Medal at the AGU Spring Meeting Honors Ceremony, which was held on May 27, 1998, in Boston, Massachusetts. The John Adam Fleming Medal recognizes original research and technical leadership in geomagnetism, atmospheric electricity, aeronomy, and related sciences.


“Professor Donald M. Hunten is a model for all of us engaged in the study of planetary atmospheres. He is first of all a superb scientist, one of the finest aeronomers our planet has produced. He is that rare combination of instrumentalist, observer, theorist, and responsible representative of his field that makes a “compleat” scientist.

“Don’s contributions are evident everywhere in the record of terrestrial and planetary aeronomy. In the 1950s, he was preeminent among those who developed the ground-based instruments that obtained the spectra required for an understanding of the excitation of Earth’s airglow and aurora, and he also developed the theories that explained the data. Together with W. Fastie and L. Wallace and his student L. Broadfoot, Don was among the first to instrument and fly the sounding rockets that acquired in situ observations of the same phenomena in the visible and ultraviolet.

“From the Earth and sounding rockets, he easily made the jump to other planets, telescopes, and spacecraft. In the early 1960s, he and J. Chamberlain contributed to the deflation of the Martian atmosphere by demonstrating the weak points in earlier attempts to derive the red planet’s surface pressure, thereby helping to save NASA the embarrassment of a proposed Martian lander whose parachute might never have opened! With R. Goody and N. Spencer, Don was the godfather of the Pioneer Venus mission and a key scientist in its highly successful implementation and the analysis of the results.

“Probably his single greatest achievement was the beautiful development of the theory of diffusion-limited escape and the subsequent analysis of escape of hydrogen from the planets. In the course of that work, he and D. Strobel and T. Donahue used combined flow and gas phase chemistry models to explain how odd hydrogen chemistry works in the Earth’s middle atmosphere and how it is related to hydrogen escape. A similar kind of analysis, this time in parallel with M. McElroy and T. Donahue, explained the perplexing mystery of the stability of the CO2 atmosphere on Mars.

“Turning to the outer solar system, Don developed a model for the atmosphere of Titan prior to the Voyager 1 encounter in 1980 that was so good it became the standard after the data came in confirming it. With his extraordinary intuition and insight, he had correctly surmised that Titan must have a massive, molecular nitrogen atmosphere, well before there was any detection of N or N2 on this intriguing satellite. In the following decade, Don used his excellent grasp of physics together with his extensive experience in deep space missions to play a critical role in the design of the Cassini-Huygens mission, now safely on its way to Saturn and Titan.

“Presently, he is analyzing data from the Galileo Probe into Jupiter’s atmosphere and investigating the tenuous, gaseous envelopes around Mercury and the Moon, showing no signs of slowing down in his endless quest for scientific results of the highest quality.

“No review of Don’s accomplishments in his chosen field would be complete without mention of his stimulation of others through teaching and wide-ranging scientific collaborations that have stressed the interdisciplinary nature of research on planetary atmospheres. He has also been extremely helpful to the scientific community, serving on endless advisory committees including the Space Science Board. He chaired others, such as COMPLEX, served a term as President of the AAS Division for Planetary Sciences, and even did a stint at NASA Headquarters. In all of these activities, as in his scientific work, Don has always maintained the highest standards and demanded them of others.

“We are delighted he is receiving the 1998 John Adam Fleming Medal of the American Geophysical Union. He is that rare recipient who brings honor to an award.

—TOBIAS OWEN, University of Hawaii


“Thank you very much, Toby, for those kind words. I was fortunate to be born at just the right time to benefit from the huge expansion of universities and of research opportunities, which began just as I received my Ph.D. at McGill University at Stuart Foster’s Radiation Lab in 1950. I was offered a postdoc at the University of Saskatchewan, where Balfour Currie had just received a huge grant from the U.S. Air Force Cambridge Research Center (AFCRC). The broad terms included work on the aurora and upper atmosphere, and I proceeded to build instruments and learn about this new field. One of the principal tools was the 1939 book by John Adam Fleming, Terrestrial Magnetism and Electricity. Although the space age was in its infancy, the work described in that book was from the age of ships, geomagnetic observatories, and ionosondes. To get more up-to-date, I devoured the papers and review chapters of David Bates, some of them written with Marcel Nicolet. Important collaborators from across the border was Joe Chamberlain, who, for a couple of years, was our AFCRC contract monitor and then joined Yerkes Observatory, and Tom Donahue; all three of us shared an interest in sodium airglow.

“In 1962, Joe invited me to join the Space Division at the newly organized Kitt Peak National Observatory in Tucson, and after arranging a leave of absence I moved there a year later. We had a sounding-rocket program and lots of telescopes, but what influenced me most was the scientific staff that Joe had assembled, especially Joe himself and Michael McElroy, who had been a student of David Bates and Alex Dalgarno. A frequent visitor was Richard Goody. Working with them and others such as Lloyd Wallace and Michael Belton, I learned the beginnings of the new field of planetary atmospheres and how to act like a theorist. I became more and more involved with NASA planetary missions, first with analysis of data from the Mars and Venus Mariners and then through the wonderful ultraviolet spectrometers flown by Lyle Broadfoot on Mariner 10 and the Voyagers. Richard Goody involved me in his successful campaign to make Pioneer Venus a reality, and a natural follow-on was the early work defining Galileo and Cassini-Huygens.

“In 1977, I moved across the street to the Lunar and Planetary Laboratory (LPL), a flourishing institution founded by Gerard Kuiper and built to eminence by Chuck Sonett. Once again, this gave me the opportunity to work with graduate students–always one of my greatest pleasures. I will mention only a few names: Gordon Shepherd, Howard Rundle, and Lyle Broadfoot at Saskatoon, and Nick Schneider, Mark Sykes, Bashar Rizk, and Ann Sprague at LPL. I have learned from everyone I have mentioned, and working with them has always been one of life’s greatest pleasures.

—DONALD M. HUNTEN, Lunar and Planetary Laboratory, University of Arizona