Mercury to send message to Earth

William Atkins
Sunday, 27 September 2009 19:02

Science - Space

Astronomers on Earth are about to learn a whole lot more about the planet Mercury as NASA’s MESSENGER spacecraft passes less than 229 kilometers (142 miles) above the planet’s surface on September 29, 2009.


The September 29 encounter with Mercury will slow down MESSENGER, which is short for “Mercury Surface, Space Environment, Geochemistry and Ranging”, so that is will be able to be captured by Mercury’s gravitational field when it passes close in 2011.

A series of gravity-assist maneuvers will be performed to reduce the spacecraft’s speed.

The September 23, 2009 NASA article “MESSENGER Spacecraft Prepares for Final Pass by Mercury” quotes Dr. Sean Solomon, the principal investigator for the mission.

Associated with the Carnegie Institution in Washington, Dr. Solomon stated, “This flyby is our final planetary gravity assist, so it is important for the entire encounter to be executed as planned. As enticing as these flybys have been for discovering some of Mercury's secrets, they are the hors d'oeuvres to the mission's main course -- observing Mercury from orbit for an entire year." [NASA]

Launched on August 3, 2004, the MESSENGER spacecraft will be studying the environment and physical characteristics of Mercury from its orbit above the planet’s surface.



[MESSENGER image: "First look at side of Mercury not seen by Mariner 10," January 14, 2008, NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington]

The images taken by the spacecraft during its September 29th flyby, the third Mercury flyby of the mission, are important so that some of the un-photographed portions of Mercury can finally be imaged.

About 10% of the planet has never been imaged by spacecraft flying in the vicinity of Mercury.

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