MESSENGER to Enter Mercury's Orbit to Answer Questions about the Planet
Mercury mission coincides with journey of New Horizons as it crosses the orbit of Uranus
by Catherine McNiff
On August 3, 2004, the MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) spacecraft achieved successful liftoff, commencing an eight-year mission "to unravel the mysteries of planet Mercury." Along the way, its team of scientists is witnessing flybys of Earth, Venus, and Mercury before the craft settles into an Earth-year-long orbit of the "innermost" planet, beginning on March 18, 2011. During the orbit, the spacecraft will travel 22.7 million miles in a highly elliptical shape that will bring it as close as 125 miles to Mercury and will range as far as 9,400 miles away from it. The all-composite spacecraft is the first of its kind and is powered by two solar panels, with energy stored in a nickel-hydrogen battery. MESSENGER's payload consists of seven scientific instruments whose sole purpose is producing data to answer six important questions about Mercury:
By answering these questions, NASA scientists hope to better understand not only Mercury, but also the origins of our own planet.
The Pluto-seeking New Horizons spacecraft shares MESSENGER's date with destiny. March 18, 2011, will mark the moment that the "ambassador to the planetary frontier" crosses the orbit of Uranus on its way to the edge of our solar system. An unmanned spacecraft equipped with an array of scientific instruments will be on board to gather information to answer four nagging questions about Pluto:
According to the New Horizons mission plan, inception date 2006, the probe has left Mars, Jupiter, and Saturn in its planetary dust. Next the craft will cross the orbit of Neptune in Aug. 2014, and will enter the Pluto system with a dramatic flight past the icy planet and its moons in July 2015.
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