Mars View - from the Mars Global Surveyor

In November 1996, NASA and the Jet Propulsion Laboratory began America's return to Mars after a 20-year absence by launching the Mars Global Surveyor (MGS) spacecraft. This mission will usher in a new and exciting era of scientific missions to study the red planet.

Over the course of a full Martian year, Surveyor will return an unprecedented amount of data regarding Mars' surface features, atmosphere, and magnetic properties. Scientists will use the data gathered from this mission both to learn about the Earth by comparing it to Mars, and to build a comprehensive data set to aid in planning future missions.

Mars and Earth shared similar conditions billions of years ago, but appear much different today. A comparison of Mars and Earth will allow scientists to understand Earth's history and possibly its future.

NASA Changes Its Mars Approach
"A wildly expensive robotic spacecraft hurtling toward Mars is on its way to freezing itself to death. Project leaders were optimistic as they made their final preparations for the Mars Polar Lander's touchdown at the Red Planet's south pole, scheduled for noon PST Friday..."

Web sites offering information on Mars and the Polar Lander mission:

_ JPL's home page has links to the latest Mars projects as well as probes sent to other planets over the last 20 years. www.jpl.nasa.gov

_ The University of California, Los Angeles, where the primary science team is based, offers a site focusing on experiments aboard the Mars Volatiles and Climate Surveyor payload: www.marspolarlander.com.

_ The Planetary Society will mirror JPL's site and offer its own content in conjunction with its PlanetFest '99 gathering at the Pasadena Center: www.planetary.org

_ The Mars Society, which advocates human exploration of the Red Planet, will mirror JPL and offer its own content: www.marssociety.org

Position of Earth and Mars

The First MGS Solar Conjunction

Mars Global Surveyor spacecraft is through the first solar conjunction period which began on April 30, 1998 and ended on May 26, 1998. The solar conjunction period marked the end of the first Science Phasing Orbit (SPO-1).

During solar conjunction, the Sun gets in between the Earth and the MGS spacecraft, severely limiting communications. In the above picture, MGS is on the verge of entering the solar conjunction period. What Happens When the Sun is Between Earth and Mars During the interval around solar conjunction the Sun obscures the line of sight between Earth and Mars, making it virtually impossible to receive radio signals from the spacecraft. The Sun is a strong source of electromagnetic activity, and it wreaks havoc with the spacecraft's radio signal, essentially reducing the spacecraft's data rate to Earth to zero for the period centered around conjunction. Mission planners and telemetry engineers define this problem area as occurring when the Sun-Earth-MGS angle is less than 7 degrees; a relatively "quiet" Sun can mean that data can be successfully returned at angles as small as 3-5 degrees. Image Refreshes Once Every Minute   Latest Images from Mars View the most recent pictures of the Martian surface.   Data courtesy of  'The Mars Global Surveyor Radio Science Team'

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