There are many misconceptions about comets: that they zoom through the sky or constantly are on collision course with Earth. Not as many as the beginning of the last century when astronomers reported traces of cyanide gas in the tail of Halley's Comet, and the panic when THE EARTH PASSED THROUGH THE TAIL! Oh, the horror! ; ) Students who attended last night's Live Chat received an up-close and personal tour of comets from astronomical researcher Dr. Lori Feaga from the University of Maryland.
64 OLC members were on hand for Dr. Feaga's presentation on the Epoxi mission. Epoxi is a Mission of Opportunity, using a 'recycled' spacecraft. Originally launched as 'Deep Impact', the probe was sent to explore comet Temple 1 by taking high resolution images and launching an impactor to smash into the surface of the comet to throw up a debris cloud that could be observed spectroscopically. After the mission, the Epoxi team came up with a plan to divert the probe's course to a second, smaller comet, Hartley 2. This was the first time that two comets would be observed up close by the same suite of instruments. That gives researchers some great comparative data to answer many questions about comets, their origins and behaviors.
Epoxi's close encounter with Hartley 2 occurred on November 4, 2010. While the comet was under direct observation from September 5th through November 25th, it was only able to resolve the nucleus of the comet for a period of three hours. Traveling at a speed of 12.3 km/sec, Epoxi came within 700km of the nucleus, providing spectacular images of the surface, outgassing, and a 'snow field' surrounding it. Most of the outgassing observed was from the sublimation of water and carbon dioxide ices.
Next week: The Stennis Space Center, NASA's premier site for the testing of advanced rocket engines. Watch for the announcement in Monday's eINSPIRE communication and then sign up on the Discussion Board. We'll see you then!
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