NASA's Messenger Readies For Close Encounter With Mercury
NASA Messenger Spacecraft to Mercury. Credit: NASA/Johns Hopkins
University Applied Physics Laboratory/Carnegie Institution of
Washington
NASA's Messenger will make its first visit to Mercury planet after
almost 33 years. It will pass by the planet very soon and revisit
permanently in 2011. Its core mission is to take high-resolution
images of the entire planet.
The Messenger spacecraft was designed and built at Johns Hopkins
University Applied Physics Laboratory in Laurel, Md. The name
"Messenger" is an acronym for MErcury Surface, Space ENvironment,
GEochemistry, and Ranging. It was launched from Earth on Aug. 3, 2004.
Most of its flight is controlled by gravity from planets Earth, Venus,
Mercury and the Sun, so it has to take a circuitous path to Mercury.
It has completed five orbits of the Sun, has orbited Earth once and
Venus twice -- all this just to ensure it reaches Mercury on Jan. 14,
2008. Messenger will pass by Mercury again in October 2008 and
September 2009 before it will settle into orbit with Mercury in 2011.
The encounter on Jan. 14 will be the first visit to Mercury since
Mariner 10's last mission to Mercury, when it flew by the planet in
1974 and made its last approach on March 16, 1975. The image shown
below is Mariner 10's first image of Mercury in 1974.
Mariner was able to capture only half of the planet, so Messenger's
main mission will be to take images of the entire planet's surface and
beam them back to earth.
The cameras on board Messenger were tested successfully; the images
below were taken on Aug. 2, 2005 via its Dual Imaging System's
wide-angle camera. The image to the left is what we will see with the
naked eye, and in the image on the right uses near infrared colors to
capture elements not seen by the human eye.
The images from Messenger will help astronomers immensely. It will
probably allow for a better understanding of history from features
seen on the planet.
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