Deep Impact

Mission Profile

Deep Impact was a NASA Discovery-class mission launched on 12 January 2005 aboard a Delta II 7925 to deliberately collide an 370 kg copper impactor with Comet Tempel 1 to excavate subsurface material for spectroscopic analysis from the mother spacecraft and from Earth-based telescopes. On 4 July 2005 the impactor struck Tempel 1 at 10.2 km/s, creating an impact flash and plume of material that was observed by the flyby spacecraft, Hubble, Spitzer, Chandra, and hundreds of ground-based observatories. The excavated material revealed abundant water ice, carbon-bearing compounds, and silicates in the comet's interior, confirming that comets are far more active and chemically complex internally than surface observations had suggested. After its primary mission, Deep Impact was redirected to fly past comet Hartley 2 in November 2010 under the EPOXI extended mission.