Mars Express reaches new orbit around Red Planet

Posted: December 30, 2003

The European Space Agency's Mars Express spacecraft performed a major maneuver today, changing its initial "capture" orbit achieved on Chirstmas morning to a new orbit needed for the probe's scientific investigations of the Red Planet.

The main engine of Mars Express fired for four minutes to turn the spacecraft into the new direction while flying 188,000 kilometers away from the planet.

An illustration shows today's orbit-changing maneuver for Mars Express. Credit: ESA
The craft had been in a highly-elliptical equatorial orbit since the Mars Orbit Insertion burn last week; it is now in an orbit around the planet's poles. Refinements will occur on January 4 to bring the new orbit tighter around Mars.

The polar orbit is required for Mars Express planned science mission, covering virtually the entire planet from its new perch. Later in January, controllers will activate the orbiter's onboard science instruments to scan the atmosphere, the Martian surface and parts of the subsurface structure.

According to ESA: "The MARSIS radar will be able to scan as far as four kilometers below the surface, looking for underground water or ice. The High Resolution Stereo Camera will take high-precision pictures of the planet and will begin a comprehensive 3D cartography of Mars. Also, several spectrometers will try to unveil the mysteries of Martian mineralogy and the atmosphere, as well as influences from the solar wind or seasonal changes."

Mars Express is expected to operate for an entire Martian year -- 687 Earth days.

Today's orbit change is critical to ongoing efforts to find the silent Beagle 2 lander.

"These key maneuvers will allow us to get even closer to Mars. They will not only allow us more frequent 'overflights' of the Beagle 2 landing area, but also ensure the beginning of the orbiter's science mission. As Mars Express is the planned main communication partner of the Beagle 2, the chances of obtaining a signal strongly increase with these maneuvers after January 4," said Michael McKay, Mars Express flight director.

Mars Express is expected to fly directly above the Beagle 2 landing site at an altitude of 315 kilometers on January 7 at 1213 GMT (7:13 a.m. EST), ESA says.

"The reduced distance, the ideal angle of overflight and originally foreseen communication interfaces between the 'mother' and 'baby' will increase the probability of catching signals from the ground," ESA says.

Beagle was previously pre-programmed to conduct planned communications attempts with Mars Express on January 6, 12, 13 and 17, officials explained yesterday. The sequence of attempts assumes Beagle has still failed to communicate with the orbiting Mars Odyssey spacecraft by the time Mars Express arrives.