February/March, 1993, Volume 2, No. 1
Thermal Emission Spectrometer ProjectMars Observer Space Flight Facility Department of Geology, Arizona State University Box 871404, Tempe, Arizona 85287-1404, U.S.A.
It became crucial to determine the temperature of Mars, to see if it was warm enough to keep water from simply freezing. The temperature of a planet can be measured through a telescope using an instrument called a thermal infrared radiometer. Thermal infrared energy, which has wavelengths about 10 to 100 time longer than visible light, is more familiar to us as "heat." A thermal infrared radiometer can determine the temperature of something without actually touching it.
In the 1920's, William W. Coblentz, a scientist from the U.S. Bureau of Standards, came to Arizona to measure the temperature of Mars using the telescopes of Lowell Observatory. Two decades earlier, Coblentz distinguished himself as a pioneer in the field of thermal infrared spectroscopy. The measurement of thermal infrared energy emitted or reflected from a substance over a range of wavelengths provides a "fingerprint" unique to each material. Coblentz was the first to look at the thermal infrared spectra of a variety of rocks and minerals.
Coblentz and his colleague Carl O. Lampland were among the first to point thermal infrared radiometers at Mars. With an average temperature below 0 degrees C (32 degrees F), they found that Mars is a chilly planet, although sometimes in summer the temperatures can rise above freezing. If Mars is sometimes warm enough to melt water, it was argued, then conditions might also be right for life to exist on the Red Planet. These temperature measurements, however, did not account for a fact learned later by astronomers-- that the atmosphere of Mars is too thin to allow liquid water to survive on the surface without rapidly freezing or evaporating.
The Mars Observer Thermal Emission Spectrometer (TES), soon to orbit Mars, combines both aspects of Coblentz's pioneering thermal infrared studies. The TES is a high-tech device that can determine both the temperature and mineral composition of the martian surface. Like Coblentz, the TES science team will conduct their studies of Mars from a facility in Arizona-- this time on the ASU campus in Tempe. Determination of martian surface temperatures is useful for modeling the climate, observing the seasonal growth and retreat of the polar caps, and determining the particle size of loose sediments. TES will also help monitor the amount of dust, water, and carbon dioxide ice suspended in the atmosphere.
Titan III rocket carrying Mars Observer lifts off from the Kennedy Space Center, Florida, at 10:05 a.m. Arizona time on September 25, 1992. The spacecraft will reach Mars on August 24, 1993.
"From here the launch was spectacular!" Philip R. Christensen, TES Principal Investigator and ASU Professor of Geology, telephoned from Florida, "the excitement from the ground was incredibly high as it took off."
A few TES personnel stayed in Tempe to celebrate the Mars Observer launch with ASU students, faculty, and staff. Nearly 100 people attended the ASU event. Visitors watched one of three televisions tuned to the NASA Select channel while snacking on miniature Mars (TM) candy bars. The Mars Observer launch took place at 10:05 a.m. Arizona time.
Martian volcano Olympus Mons is taller than any mountain on Earth. It is about 6 times higher and 50 times wider than the San Francisco Peaks volcano near Flagstaff, Arizona. Figure prepared by S. Meszaros of Phoenix. Available as NASA #83-H-246 from the National Space Science Data Center, Code 933, Goddard Space Flight Center, Greenbelt, MD 20771.
Periodically during the cruise to Mars, NASA turns on the Mars Observer instruments to assess their status and check their calibrations. The TES was first turned on November 18, 1992, for a total of 65 seconds. The data from TES were received with cheers by the TES team members and visiting reporters at the ASU Mars Observer Space Flight Facility. TES was seen to be in excellent health. A second turn-on, lasting more than two hours, took place of February 12, 1993. Now, the TES team eagerly awaits August, when Mars Observer will become the first U.S. spacecraft to reach the fourth planet since 1976.
While the TES team is busy with the mission and scientific analyses of
TES data, efforts are underway to explain the project to the public.
The Mars Observer Space Flight Facility is designed with visitors in
mind. Pictures and displays outline the Mars Observer and
TES mission. Educational videos and
Select TV are shown on a
monitor in the lobby. Eventually, new images of Mars from the
Observer Camera will also be displayed. Huge windows in the
Facility allow visitors to see the TES team at work, either analyzing
TES data or testing computer commands on the full-scale TES engineering
Groups of school children frequently come to the facility-- visits can be arranged through the ASU Visitor Center, (602) 965-0100, or the Mars Observer Space Flight Facility, (602) 965-1790. The TES group is also beginning a series of Educators' Workshops, the first was held on February 20, 1993, and attended by more than 130 (K-12) teachers.
NOTE ADDED 27 Jan. 1994: The ASU Visitor Center no longer handles tours. Please call (602) 965-1790 if you have questions about visiting the facility.
[A comprehensive review of everything we know about Mars. H.H. Kieffer is a TES scientist.]
[b] Name the Russian Mars Rover (to land in 1997), open to kids born between 1/1/80 and 12/21/84 (deadline: 10/1/93).
Text by: K. S. Edgett
Assistance with original text:T.E. Montoya
Reviewed by:TES staff
Original Text: February 1993 This On-line version: January 27, 1994