How Mars Odyssey Works

By: Kevin Bonsor
mars odyssey pic
The Mars Odyssey spacecraft journeyed for more than six months before placing itself in orbit around the red planet in October, 2001.
AFP/Getty Images

The book and movie, "2001: A Space Odyssey," famously predicted that humans would have made great strides in exploring our solar system by the beginning of the 21st century. By 2001, Mars would have long been achieved, and we would already be flying manned missions to Jupiter. Of course, manned missions to Mars remain a very long-range goal, and Jupiter can only be reached in movies.

Mars Odyssey Image Gallery



­However, NASA honored the impact that Arthur C. Clarke's book and Stanley Kubrick's movie have had by naming its 2001 mission 2001: Mars Odyssey. The Mars Odyssey spacecraft journeyed for more than six months before placing itself in orbit around the red planet in October, 2001. Its main objective was to scour the planet's surface to find out what the planet is made of and if there is any water or ice to be found there. There's still debate about whether water exists or ever existed on Mars. This is an important question, because if water does exist, it means that Mars might harbor life. It would also be very useful to astronauts who may one day go to Mars.

Mars continues to fascinate us, and NASA continues to move forward in its goal of sending a manned mission there within this century. In this article, we will look at this crucial step toward putting a person on Mars. You will learn how the Mars Odyssey spacecraft gets to Mars and how it examines and determines the elemental composition of the planet.




The Spacecraft

A look at the various components of the Mars Odyssey Orbiter
Photo courtesy NASA

Is there or is there not water on Mars? There have been reports that have backed up both sides of the debate. Here are just a few of the articles written on the subject:

This type of interplanetary probe is amazing in how it retrieves data and relays that information millions of miles back to Earth.


The Mars Odyssey Orbiter is equipped with three scientific instruments that it uses to explore the Martian surface and atmosphere. Let's take a look at each of these:

  • Gamma-ray spectrometer (GRS) - This device measures just how much hydrogen exists in the upper 3 feet of the planet's soil. The amount of hydrogen found gives scientists some evidence about the existence of water on Mars. (more information on the GRS)
  • Thermal emissions imaging system (THEMIS) - This instrument identifies rock and mineral types on the planet's surface and searches for traces of hydrothermal activity. Information gathered from THEMIS helps determine safe landing sites for future missions. (more information on the THEMIS)
  • Martian radiation environment experiment (MARIE) - Scientists are curious about the amount of radiation humans will be exposed to during a possible manned mission. MARIE gathers data about radiation on the planet. (more information on the MARIE instrument)



Mission to Mars

Photo courtesy NASA

On April 7, 2001, the Mars Odyssey Orbiter took off from Cape Canaveral, FL, onboard a Boeing Delta 7925 rocket. It traveled for approximately six months before positioning itself into an initial elliptical capture orbit. After a propulsive maneuver into a 25-hour capture orbit, aerocapture was used over the course of 76 days to achieve the two-hour science orbit. Aerocapture involves using the Mars atmosphere to slow down and attain orbit.

The orbiter's final operational altitude is about 250 miles (400 km) above Mars in a sun-synchronous polar orbit. In the following two years, the orbiter maps the planet's surface and takes measurements about radiation and elemental composition.


The Mars orbiter is just one in a series of orbiters, rovers and surveyors that NASA plans to launch toward Mars in an effort to learn as much as possible about the planet before sending a human mission there. In the next decade, the U.S. space agency will launch at least one Mars exploration spacecraft in every odd numbered year.

For more information on Mars Odyssey and related topics, check out the links on the next page.