NASA’s 2001 Mars Odyssey spacecraft turned its
multipurpose camera homeward last week and took its first
picture — a shot of a faint crescent Earth — as the
spacecraft heads off toward its destination, the planet Mars.

The image was taken as part of the calibration process
for the thermal emission imaging system, the camera system
that is one of three science instrument packages on the
spacecraft. The imaging system will study the Martian surface
in both visible and infrared light and will help determine
what minerals are present. It also will map landscapes on Mars
at resolutions comparable to that of NASA’s Landsat Earth
observing satellite.

“The spacecraft team did a fantastic job to image the
Earth. These images are spectacular, especially given how far
away we were. They have given us the first-ever thermal-
infrared view of Earth and the moon from interplanetary
space,” said Dr. Philip Christensen, principal investigator
for the spacecraft’s thermal emission imaging system at
Arizona State University, Tempe.

The visible light image shows the night side of the
crescent Earth looking toward the South Pole. Taken at the
same time, the infrared image measures temperature, showing
its “night-vision” capability to observe Earth even in the

“The instrument measured a low surface temperature of
minus 50 degrees Celsius (minus 58 degrees Fahrenheit) for
Antarctica in winter, and a high of 9 degrees Celsius (48.2
degrees Fahrenheit) at night in Australia,” Christensen said.
“These temperatures agree remarkably well with observed
temperatures of minus 63 degrees Celsius at Vostok Station in
Antarctica, and 10 degrees Celsius in Australia. Thus we
demonstrated that the instrument can accurately measure
temperatures, even from a distance of more than 3 million
kilometers (2 million miles).”

These observations of Antarctica provide an excellent
test for how the imaging system will perform at Mars, where
afternoon temperatures are comparable to those in the winter
night at Earth’s South Pole. The Antarctic continent, which
was uncharted less than 100 years ago, was the last landmass
observed by Odyssey as it left Earth on its way to Mars.

The images were taken on April 19 and are available at


The Odyssey spacecraft continues to be in excellent
health with all its systems working normally.

“Not only was this a successful calibration of the
instrument, it demonstrated that we can accurately point the
spacecraft, and it put the team members through their paces,”
said David A. Spencer, the Odyssey mission manager at NASA’s
Jet Propulsion Laboratory (JPL), Pasadena, Calif.

Today at 5 a.m. Pacific time, Odyssey was 4,639,830
kilometers (2,883,050 miles) from Earth and traveling at a
speed of 3.3 kilometers per second (7,474 miles per hour)
relative to the Earth.

More information about the Mars Exploration Program can
be found at

The Mars Odyssey mission is managed by JPL for NASA’s
Office of Space Science, Washington, D.C. JPL is a division of
the California Institute of Technology, Pasadena. The Odyssey
spacecraft was built by Lockheed Martin Astronautics, Denver.
The thermal emission imaging system was built by Raytheon
Santa Barbara Remote Sensing, Santa Barbara, Calif, and is
operated by Arizona State University.