Online From Jupiter 97
Dr. Glenn S. Orton
Roles for Galileo Mission:
When I was seven, my parents gave me a book called "Children's Wonder Book of Knowledge" with a neat little chapter on "Dogs" which gave a picture and a short description on each page of a breed of dogs. This was followed by similar chapters on "Cats", "Birds", "Horses" and "Insects". At the back of the book, there was a curious chapter which didn't quite fit this mold; it was called "Stars", and I fell in love with it, memorizing pages of its words and pictures. The most fascinating of the pictures - paintings, really, since this was years before spacecraft like Pioneer and Voyager - were of planets. These were the pages where I spent most of my time. More books, more years, and at least two backyard telescopes later, I found myself hoping that I could do work in planetary astronomy professionally. My high school junior and senior year science fair projects were on Jupiter, a planet on which I would spend considerable attention later in life.
I went to college at Brown University in Providence, Rhode Island, where I studied physics. I did a senior honors thesis in the Geology Department, where I worked on models of recently discovered lunar mass concentrations. One of my professors suggested that I apply to a new planetary science program at Caltech. To my amazement, I got in.
Brown was only 15 miles over the Massachusetts border from where I had grown up, a small exurban bedroom community of Swansea. I had been born in 1948 not much further away in the mill city of Fall River, pretty much known only for the Lizzie Borden "perfect murder" case. Going to Caltech was a big leap in a complicated year--1970. My Selective Service draft lottery number was 23; this was a very low number out of a possible high of 365, and it meant that (a) I could wait to be drafted, with the distinct possibility of being shipped to Vietnam in the height of the U.S. military involvement there, (b) I could seek out the officer corps in the Navy, Coast Guard or Air Force, where the possibilities of surface combat were a little more remote, and there might be some reasonable educational opportunities, or (c) I could minimize the time I spent away from studies and try to find a reserve unit of some kind close to Caltech, even though it meant that I'd be committed for 6 years.
After being accepted in the Coast Guard and Air Force, and finding that there was a single California Army National Guard unit vaguely close to Caltech, I opted for (c) and (after shaving!) became a member of the California National Guard. I spent one weekend a month and two weeks in the summer at Ft. Irwin (in the middle of the upper Mojave Desert) and later Camp Roberts (near San Luis Obispo, a new miles inland from the California coast).
That first summer in Pasadena, I started working on issues involving radio waves propagating (travelling) through the solar corona (the outermost layer of the Sun's atmosphere). Then came the call to a few months of active duty training for the National Guard provided by the U.S. Army - in Fort Knox, of all places! When I interviewed for the Burbank Guard unit, I asked what sort of positions were available, they asked whether I could touch type, and - not being a complete fool - I answered "Sure!". Actually I typed about 50 words per *hour*, but in a couple of weeks that became 50 words per minute. There's nothing like raw motivation!
When I got the call to active duty training, I discovered that I was listed as a Supply Clerk specialist. This position, of course, required NO typing skills of any kind (although I'm not at all sorry that I can touch type now - it's extremely handy in this age of computer terminals). Later, I was promoted to the position of the unit Armorer, having - of course - absolutely NO non-military experience with firearms of any sort (nor desiring any).
All this was a mild diversion in my graduate student career, which had an interesting first year. There were 5 people in the Planetary Science first-year graduate student corps in 1970-1971, including me. I left for Ft. Knox on military leave of absence before they all arrived. By the time I returned in January of 1971, greeted by no less than the San Fernando earthquake a couple of weeks afterward. I had discovered that there were only 3 people left in the program - two had dropped out already! Another student left at the end of the school year with a Master's degree, leaving only me and one other student. This other fellow had taken the whole summer off before starting to prepare the 4 small pieces of research which were judged as our qualifying exams (which you must pass to be allowed to continue in the program). I had worked on my major piece of research since January, on the other hand, and I found it hard to believe that the other student would have a chance. Apparently the faculty on his qualifying exam agreed, and I found that I was the only person remaining.
Rumor was that if the faculty was happy with you, you only needed to describe your first research topic (the only one which you had invariably spent most of your time). Maybe your second one would come up if they wanted to be convinced of your qualifications over a broader field of work. Conventional wisdom had it that you found yourself describing your third and fourth topics, you were in great trouble.
On the fateful afternoon, I found myself after a short break in a two-hour session being invited to return and describe my third and fourth topics. My first two topics were about 1) putting limits on the atmosphere and surface conditions of Venus using a combination of passive radio and active radar data, and 2) analyzing thermal infrared data on Venus to show how it depended on location relative to the Sun - it was, strangely enough, hotter on the *midnight* side of the planet.
My third topic was one in which I had spent some time preparing basic models of the interior of Mars, limited by measurements of the planet. Unlike the first three projects, my fourth was a hardware-oriented project completed just in time for the exam in which I created a "cradle" which could tilt a piece of glass, heated by a kitchen hotplate, over a wide range of angles beneath an infrared detector. The idea behind this project was to check that measuring the emission from the glass surface (a rough model for a planetary surface ) in two different ways gave roughly equal answers. It did. This fact made me think that this whole topic had merely been a clever way for the faculty to discover how klutzy I was in the machine shop! After two more hours and some waiting, I had discovered that I never was in much trouble. With only me left, they were just genuinely interested in the last two topics. It was about this time that one of my committee members said that he had just taken some infrared observations at Palomar Observatory on the 200-inch telescope (metric was slow to come to these historical facilities, and only recently among astronomers ranking world-wide telescopes would become more common to refer to it as the Palomar 5-meter telescope). He and a collaborator had investigated an emission feature in Jupiter. This feature could be either emission from the deep atmosphere, or emission by hot methane gas in a hot Jovian stratosphere, something no one had predicted. Looking at Jupiter in light with a wavelength near 7.8 microns from the center to the edge of the visible disk of Jupiter (the limb), and discovered that it was brighter there - indicating that the hot stratosphere interpretation was correct. Near 8.5 microns wavelength, away from the methane spectral feature, this "limb brightening" effect went away.
So, it was suggested that I use a little more Palomar time and attempt to use the data to do a real model of the temperature structure of Jupiter's atmosphere. I ended up going to a Workshop on Jupiter's atmosphere, where I met people who were doing similar work in preparation for the newly announced Mariner Jupiter Saturn mission which would later be renamed Voyager. I found that I'd have to learn to model much of Jupiter's spectrum in many regions before I'd be fully successful at constructing a model that would be considered complete by anyone else in the field.
About that time, the Pioneer 10 results came in for the Infrared Radiometer (IRR) whose investigative team included Drs. Guido Muench and Gerry (sounds like 'Gary') Neugebauer of Caltech's Division of Physics, Math and Astronomy, and one of Dr. Munch's former graduate students, Dr. Larry Trafton who was now at the University of Texas, Austin. The Pioneer infrared investigators' models for the thermal emission were supposed to show the total thermal output for all wavelengths of light and also give the relative amounts of molecular hydrogen and helium, the fundamental two constituents of Jupiter's atmosphere. The models failed to fit the data, however; they were too dark near the limb of Jupiter. I applied my models which included a hot stratosphere and things began to look a little better.
Finally, back when it wasn't clear whether we would have a clear night at Palomar for our observing, my thesis committee suggested that I do work at the Mt. Wilson 60-inch telescope to measure the visible spectrum of different features on Jupiter, such as the dramatic dark and light "bands" on Jupiter called belts and zones. This rounded out my graduate research on Jupiter.
After finishing graduate school, I went to JPL and continued working on studying Jupiter, concentrating on the planet's infrared emission. I added data from the Pioneer 11 spacecraft, and also some observing from the Kuiper Airborne Observatory, an airborne telescope carried by a C141 transport aircraft. These measurements included both Jupiter and Venus and allowed us to look at more wavelengths than was possible using the Pioneer spacecraft infrared experiment.
While at JPL, I consulted with another postdoc, Dr. Linda Brown, a molecular spectroscopist working on better models of atmospheric gases - mostly methane (CH4) which is very important for Jupiter. These meetings become more personal and we married in late 1978. When I tell people that we met over methane, I suppose they have a mental image of us sitting on a cow! In 1986 and 1988 we adopted two infants from Korea who became (several visits to the Federal building for visa and citizenship, and court visits for the formal adoption procedure later) our children: Gregg Segi ("world-wide strong spirit") Brown Orton and Sarah Suyun ("extraordinarily pretty as a lotus") Brown Orton. This means that in our immediate family, no one who is biologically related to anyone else. People ask what Linda and I talk about at home, few realize that almost all our conversations center on various aspects of on-the-job-training in early childhood education!
There were other opportunities to work on future spacecraft that could collect infrared data. One of these was the Mariner Jupiter Uranus mission opportunity. A colleague and I wrote up a proposal, along with many other people. After receiving all these proposals, NASA promptly abandoned the mission concept - the lesson was not wasted on me, although I wasn't quite sure what it was.
We put in another proposal for an infrared instrument for the Jupiter Orbiter/Probe mission, and I also applied for a position on a team being formed for the mission's proposed infrared spectrometer - a spare from the Voyager mission. As a real longshot, I wrote a proposal to be an Interdisciplinary Scientist (IDS), a new category in which investigations could be proposed using data from several different experiments. I thought that it would be a good idea to try to relate the Probe and Orbiter experiment results: that is, to use the Probe data as a means of providing "ground truth" for the remote sensing Orbiter experiments. Likewise, the Orbiter data could be used to extend the Probe results and generalize them for the planet as a whole. To my amazement, while the hardware experiment was not accepted, my proposal as a knowledgeable "graybeard" was. Then another group-- the investigation team for the Photopolarimeter-Radiometer (PPR), a hybrid instrument investigating the reflection and polarization properties of Jupiter's clouds and its total energy input and output- - asked whether I would work on their experiment as well doing some design work. I said 'yes', not realizing that the entire mission (later to be named "Galileo") experience would be a very long one, indeed.
What's up now? I was just promoted to Senior Research Scientist (it's a jolt to be called senior ANYTHING!), and I've come off a year of giving monthly talks on the Shoemaker-Levy 9 comet collision with Jupiter and "what I saw." Currently, I'm working to support almost monthly observations of Jupiter in the infrared from the NASA IRTF. I'm also working hard to get some analysis programs which have gotten bogged down up and out the door in time for the Galileo encounter starting December 7, 1995. It's always been clear, at least since Galileo's antenna did not open properly, that we need ground-based observations of Jupiter, partly to supply the global and regional context that the spacecraft cannot support on its now very limited communications link. Maybe more importantly, it will be necessary to target specific features of interest to the Orbiter investigation using ground-based global images. Plus, I'm looking forward to being involved with the Cassini mission to Jupiter, which is due to arrive at Saturn in the next century (I'm trying to stay healthy and fit!)