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Deep Impact
Deep Impact (EPOXI) Mission to Earth's Moon Deep Impact (EPOXI) Mission to Earth Deep Impact (EPOXI) Mission to Beyond Our Solar System Deep Impact (EPOXI) Mission to Comets

Goals: Deep Impact's primary mission was to probe beneath the surface of a comet. The spacecraft delivered a special impactor into the path of Tempel 1 to reveal never before seen materials and provide clues about the internal composition and structure of a comet.

Accomplishments: After almost nine years in space that included an unprecedented 4th of July impact and subsequent flyby of a comet, an additional comet flyby, and the return of approximately 500,000 images of celestial objects, NASA's Deep Impact mission ended in September 2013.

Deep Impact, history's most traveled deep-space comet hunter, provided many significant results for the science community. Here are the mission team's top five:

  1. First determination that a comet's surface layer (few to 10 meters or so) is very porous (greater than 75 percent empty space)
  2. First direct evidence showing chemical diversity of outgassing associated with different parts of the cometary nucleus
  3. Discovered that hyperactive comets (5-10 percent of all comets) are driven by carbon dioxide and that the observed excess water is from icy grains in the coma. The processes of hyperactive comets are very different from those in normal comets.
  4. Observations led to re-thinking where in the solar system comets formed. Contrary to all thinking, for the last half century, the Jupiter family comets must have formed closer to the sun than did the Oort cloud comets.
  5. Enabled the subsequent exciting results from the Stardust NExT mission that changes theories on how comets evolve.
   

Banner says visit the Deep Impact Legacy Site
Key Dates
12 Jan 2005:  Launch
4 Jul 2005:  Comet Tempel 1 Impact
4 Nov 2010:  Comet Hartley 2 Encounter
8 Aug 2013:  Communication with Spacecraft Lost
Status: Successful
Fast Facts
Deep Impact Facts Deep Impact was the first mission to eject material from a comet's surface.

It is a coincidence that Deep Impact shares its name with a 1998 science fiction disaster film about a comet.

Author Arthur C. Clarke suggested the idea of impacting a comet in his novel 2001: A Space Odyssey

Deep Impact's small probe was the first manmade object to collide with a comet (right).

EPOXI has double meaning. EPO stands for EPOCh the Extrasolar Planet Observation and Characterization phase of mission. XI is short for the spacecraft's extended investigation of comets.

EPOXI is an entirely new mission for a spacecraft already in orbit around our sun.
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Last Updated: 9 Apr 2014