Live From Mars was active July 1996-December 1997.

Meet: Philip Christensen

Principal Investigator,Thermal Emission Spectrometer
Arizona State University, Phoenix

My Journals

Who I Am

I am a professor at Arizona State University where I work as a planetary geologist. I teach courses on the solar system, the geology of Mars, and the use of satellite images and data to study planetary surfaces (also known as remote sensing). My main research interests center on understanding the early history, evolution and current conditions on the martian surface.

My Career Journey

I have been fascinated by the planet Mars since I was a kid. I once talked my mom into letting me stay home from school in the sixth grade to watch the first images of Mars coming back from the Mariner 4 spacecraft that were being shown live on TV. Growing up in Los Angeles I got an opportunity to go to the Jet Propulsion Laboratory and see firsthand one of the Surveyor spacecraft that eventually landed on the Moon. I followed the Apollo missions to the Moon in high school and continued to watch the early spacecraft missions to Mars. As a college student at UCLA, it never occurred to me that I could actually get a job studying Mars but, as a senior, I got a job in a research lab cutting and filing Mariner 9 images of Mars. Working on this project suddenly made me aware that it might be possible to study Mars as a career, and I eventually enrolled in graduate school at UCLA. In my graduate work I used data from the Viking orbiters and landers to study martian climate change, the sedimentary cycle (erosion, transportation and deposition), aeolian (wind) processes, and volcanic processes.

What I Do

The excitement of being directly involved with a NASA planetary mission inspired me to continue to participate in the exploration of Mars. My work over the past decade has focused on building an instrument, called the Thermal Emission Spectrometer, or TES, which will fly on the Mars Global Surveyor (MGS) spacecraft. This instrument was built by the Santa Barbara Research Center in California, and I figure I've made over 125 trips to Santa Barbara in the past 10 years. TES will map the martian surface from orbit to determine the composition of the minerals present there. A major objective of the TES experiment will be the search for minerals and rocks that provide evidence for ancient water-rich environments on Mars, which may hold clues to the possible existence of past life on Mars. The recent announcement of the possibility of ancient life on Mars has made this search even more important. The TES experiment will also provide a better understanding of the composition of volcanic rocks, weathered soils (dirt), ices, the fascinating deposits in the polar regions, and atmospheric clouds and winds.

The TES we have built for the MGS is actually the second TES we've built. The first was on the Mars Observer spacecraft, which failed just three days before it was to go into orbit around Mars in 1993. That failure made me, and all of the students, scientists, programmers, and data processors who worked on Mars Observer, very aware of how complex and risky sending spacecraft to other planets can be. Fortunately, it made all of us even more determined to make the project work and to carry on the exploration of Mars.


I live in Tempe, Arizona with my wife, Candi and two kids, Kevan, age 8 and Alexandra, age 7. One positive note on the failure of Mars Observer - my kids were very young when that mission was launched and really weren't aware of what was going on. They will be going to Cape Canaveral again with us in November, and it gives me a tremendous amount of satisfaction to be able to share with them what we're doing; this time they can really appreciate where the MGS is headed and what it will accomplish.