Donald M. Hunten
Donald Mount Hunten
March 1, 1925 - December 14, 2010
Statement from the Lunar and Planetary Laboratory, University of Arizona
December 21, 2010
Reposted from http://www.lpl.arizona.edu/spotlight.php?ID=76
On December 14, 2010, LPL lost Don Hunten after a long illness. During his
last days, Don was tended with loving care by our colleague and his wife and
colleague, Ann Sprague.
Don's scientific career began with the study of physics at McGill University,
where he obtained a doctorate in 1950. While a faculty member at the University
of Saskatchewan his research concentrated on the study of aurorae. By 1963
however the space age was starting in earnest. At the invitation of Joe
Chamberlain, Don moved to Kitt Peak National Observatory in Tucson (now NOAO)
to join the newly formed space research group and his main interests switched
to the study of planetary atmospheres. Thus, Don joined the first group of
pioneers in the scientific exploration of the solar system and he was to be a
leading figure in this community for nearly half a century.
The accomplishments of these pioneers were remarkable, including the first
characterizations of the atmospheres in our solar system along with development
of the basic understanding of the structure and chemistry of these atmospheres
and the experimental and theoretical tools used to study them. Many of the
ideas developed during that time are still with us today and Don's
contributions were central to their development. A signature achievement
during this phase of Don's career was an understanding of how odd hydrogen
chemistry stabilized the atmosphere of Mars against destruction by
photodissociation. Don moved to the Lunar and Planetary Laboratory of the
University of Arizona in 1974 and his involvement in planetary research
continued unabated. He also taught numerous students and post doctoral
associates. Don retired in 2001, but remained active until recently. He
received many honors during his career, including induction into the National
Academy of Sciences, the Kuiper Prize of the Division of Planetary Sciences of
the American Astronomical Society, and a Regents' Professorship at the
University of Arizona.
One of Don's most far reaching achievements concerned the role of diffusion in atmospheric escape processes. "Hunten's Principle," as this is sometimes known, described how the escape rate was limited by diffusion of the escaping species through the background atmosphere. The theory was beautiful in its clarity and showed how the escape rate was independent of many complicating factors, chemistry, vertical mixing, etc. and led to a simple and accurate formula. Typically for Don, the theory was formulated in response to an observation, the detection of molecular hydrogen in Titan's atmosphere, when it was expected to have a very low abundance because of rapid escape. The theory was developed in a series of papers in 1972-1974 including an application to the escape of hydrogen from the terrestrial atmosphere---one of the best examples of how studying other planets leads to a better understanding of our own.
Don was a major influence on the unmanned space program with involvement in the planning and execution of numerous NASA planetary missions including Pioneer Venus, Voyager, Galileo and Cassini. In fact, Don was the godfather of so many mission that some of us took to calling him "The Don." I'm not sure that he knew, but I don't think that he would have minded. In addition to his direct involvement on the experiment teams, Don help conceive these missions, argued for their funding, sat on (and often chaired) their planning committees, helped to define the scientific goals, and provided wise guidance during their execution. The scientific legacy is enormous.
Don was a scientist of extraordinary breadth. His expertise ranged across the planetary sciences from chemistry to remote sensing to thermal processes to studies of atmospheric evolution and he used a variety of tools including telescopic observations (often with instruments that he designed and built himself), spacecraft observations, and theoretical investigations. With a penetrating intellect and an encyclopedic memory, Don would get to the heart of a problem with a speed and precision that sometimes left the rest of us feeling rather embarrassed and dull-witted. A talented tinkerer, Don could build a harpsichord in his garage, or repair your PC with the needle-nosed pliers and soldering iron that he kept in his office, all the while with gentle classical music playing in the background. He wrote nearly as many papers on electronics as he did on atmospheric evolution. Content for most of his career to work out results analytically, or employ code-savvy younger scientists for calculations, Don waited until he was nearly 80 years old to learn fortran programming, because, I suspect, he finally had the time. May we all maintain such intellectual ambition.
Throughout his career, Don went out his way to support and encourage younger scientists. He was extremely generous with his time, advice, and insight. As a result, Don leaves behind legions of students and collaborators that he profoundly influenced. These intellectual disciples can be found in every planetary science research center on the globe. Don's textbook, co-authored with Joe Chamberlain, "Theory of Planetary Atmospheres," was the bible for many of us. This pales though, in comparison to personal interactions, through which Don could more directly impart his common sense approach to planetary science. Those of us that were fortunate enough to be exposed to this wisdom received an extraordinary gift and will miss him greatly. His spirit lives on in the work that we do.
Distributed by Athena Coustenis, Division for Planetary Sciences, American
Donald Mount Hunten passed away on the 14th of December, 2010.
He was born in Montreal, before his family moved to London, Ontario where
Don attended the Western Ontario University In 1946 he enrolled in the Ph.D.
program at McGill University, back in Montreal, where he obtained his PhD in
1950. He later became assistant professor at the University of Saskatchewan.
After Joe Chamberlain moved to Kitt Peak National Observatory in Tucson to
form a space research group, he invited Don to join it and so Don moved to
Tucson. In 1974 he became professor at the Lunar and Planetary Lab.
In 1982 he was inducted into the National Academy of Sciences and he
eventually became a Regents Professor at LPL, UA.
Borrowing from a citation by T. Owen at the 1998 John Adam Fleming Medal of
the American Geophysical Union honoring Don:
"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. In the early 1960s, he contributed to the deflation of the Martian
atmosphere by demonstrating the weak points in earlier attempts to derive the
red planet's surface pressure. Don was the godfather of the Pioneer Venus
mission and a key scientist in its highly successful implementation and the
analysis of the results.
One of his greatest achievements was the development of the theory of
diffusion-limited escape and the subsequent analysis of escape of hydrogen
from the planets. 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."
Don Hunten also worked on the analysis of data from the Galileo Probe into
Jupiter's atmosphere and investigated the tenuous, gaseous envelopes around
Mercury and the Moon. He has been an inspiration and a mentor for many of the
currently confirmed planetologists.
An Autobiographical Comment
Don Hunten, November 12, 2010:
I was born in Montreal, where I spent my first three years, and we then moved
to London, Ontario where my father had obtained a chemistry professorship.
Before long he designed and built a cottage at Rondeau on Lake Erie where we
spent many happy summers. I became a choirboy and from the age of 6 took
piano lessons. After I finished high school I attended my father’s university,
Western Ontario. I took a program in chemistry and physics because I was
interested in both subjects, but the third-year organic chemistry lab convinced
me to become a physicist. These were war years, and we spent three hours every
weekday in the University Air Squadron, then in the last year the Canadian
Officers Training Corps. In my senior year the war was over and we could spend
full time on our studies. I was not becoming a good pianist and switched to
clarinet and many years later switched again to the bassoon. I then (1946)
enrolled in the Ph.D. program at McGill University, back in Montreal, where
I saw a lot of my Auntie Dolly. Graduate students normally were also employed
as "demonstrators", lab assistants, and it was in the Electricity and Magnetism
lab that I met Ann Rubenstein. When I later met her family I learned that
those students called me "flannel feet" (a radio character) on account of my
rubber-soled shoes. Ann took a shine to me, and I enjoyed many dinners and
bridge games at her parents' house and cottage on beautiful Lake Memphremagog
to the southeast on the Vermont border. Shortly before I obtained my PhD in
1950, we were married, Ann took a job with the Red Cross blood transfusion
service, and we took residence in a one-bedroom apartment
I wanted a university job in Canada, and the only one I found was as a
post-doc at the University of Saskatchewan. We bought an old car and drove to
Saskatoon. I started lecturing along with my auroral research, and soon
became an assistant professor. Ann had always been interested in fossils, so
after her chemistry degree from McGiill she started taking geology courses.
She did not get another degree because women were not allowed to take the
field trip. She also gave birth to Keith and Mark in 1962 and 1964.
My initial job was supported by a huge (for those days) contract from the
U.S. Air Force. The contract monitor was Joe Chamberlain, and this led to
our first acquaintance.
Later he joined the Yerkes Observatory of the University of Chicago, which had
another USAF contract for auroral research, and we collaborated. In 1963 he
moved to Kitt Peak National Observatory in Tucson to form a space research
group and invited me to join it. I took a 3-year leave of absence from the
University, and got so involved with NASA that I decided to stay in Tucson.
By 1964 most of our group, including Joe, had left. I noticed that the Lunar
and Planetary Lab next door was getting very good, and I asked for, and
received, a professorship. At about this time I was urged by several
colleagues to take a temporary job at NASA Headquarters in Washington and
I spent six months there. In 1982 I was inducted into the National Academy of
Sciences and I eventually became a Regents Professor at LPL, UA.
One of my students was Ann Louise Sprague, and after she obtained her PhD she
moved to a NASA center for a year. She then requested a post-doc job back in
Tucson and we engaged in an extensive telescope-observing program. We fell in
love. I left Ann Hunten who divorced me. Ann Sprague and I were then married.
We bought a house in the Starr Pass area of Tucson, which we sold in 2010 so
that we could move to the retirement community of Quail Creek. Two years
previously I had a stroke that paralyzed my left side. After much effort,
physical therapy, and loving encouragement I considerably recovered; able to
walk with a walker but with a left arm and hand still weak.
Addendum by Ann Sprague, December 15, 2010:
Don suffered another devastating stroke on 23 Nov 2010. He painfully left
his family, friends, Science, and this Earth at 3:45 a.m. the fourteenth of
A Personal Remembrance by Mark V. Sykes, December 18, 2010:
We have lost another major figure in our profession with the passing of
Don Hunten. I was Don's first student to graduate from LPL back in the 80s and
I shall miss him very much. In addition to being a noted and admirable
scientist, Don was a fine musician, playing early music on wind instruments
with the University's Collegium Musicum. He even built a harpsichord. Don was
unstintingly generous of his time and resources to graduate students when I
was in the department. He would often use his own grant money to pay for the
travel of other faculty's students to the DPS (and I am not talking about 1 or
2, but 5 or 7!). He was broadly knowledgeable and as my advisor put up with (and
financially supported) my own forays into subject areas outside his own
discipline of planetary atmospheres. He was patient, but would not stand
any bloviating. He was a favorite target of
imitation by students and others in the field - and I fondly remember doing his
voice in a cart covered with his blue sweater in the grad student skit
"Hunten's Brain" (a huge cauliflower, set within a fog of carbon dioxide, with
wires coming out, one into his Pioneer Venus coffee cup,
and surrounded by walnuts representing the brains of former graduate students).
Don continued to be scientifically productive through strokes, publishing
single-author papers in Nature and Icarus until just a couple of years ago.
His body finally failed, but his mind never did.