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Impactor targeting Sensor (ITS)

NSSDCA ID: 2005-001D-01

Mission Name: Deep Impact Impactor (DII) Vehicle
Principal Investigator:Dr. Michael F. A'Hearn


Impactor Targeting Sensor (ITS) is designed to navigate the Deep Impact Impactor (DII) to the comet. The ITS is the primary targeting camera on DII, mounted inside the impactor with its boresight aligned with the velocity vector. It looks through a rectangular hole cut out of the copper cratering mass in the front of the DII. The ITS is a duplicate of the Medium Resolution Imager on the Deep Impact flyby bus but does not have a filter wheel. The ITS consists of a telescope and Charged-Couple Device (CCD) camera. The telescope is of Cassegrain design, f/17.5 with a 12 cm diameter aperture and a 2.1 m focal length. It houses light baffles and zerodur glass primary and secondary mirrors. The camera uses a 1024 x 1024 split frame transfer CCD. The field of view is 10 milliradians (0.587 degrees, or 10 microradians/pixel) allowing a surface resolution of 0.2 meters at 20 km. Full frame readout time is 1.8 seconds, faster readout of centered sub-frames is also possible. The last image taken, about 30 seconds before impact, had a resolution of about 3 meters per pixel. This image was degraded, indicating abrasion of the lens due to dust impacts, as was expected when the Impactor got close to the nucleus. The images were transmitted to the flyby bus and re-transmitted to Earth.

Alternate Names

  • Deep Impact Impactor Targeting Sensor - Visible CCD
  • DeepImpactImpactor/ITS
  • ITS
  • urn:nasa:pds:context:instrument:dii.its

Funding Agency

  • NASA-Office of Space Science Applications (United States)


  • Planetary Science: Small Bodies

Additional Information

Questions and comments about this experiment can be directed to: Dr. David R. Williams



NameRoleOriginal AffiliationE-mail
Dr. Michael F. A'HearnPrincipal InvestigatorUniversity of Maryland

Selected References

  • Hampton, D. L., et al., An Overview of the Instrument Suite for the Deep Impact Mission, Space Sci. Rev., 117, No. 1-2, 43-93, Mar. 2005.
  • Wellnitz, D. D., et al., The location of the impact point of the Deep Impact Impactor on Comet 9P/Tempel 1, Icarus, 222, No. 2, 487-491, doi:10.1016/j.icarus.2012.08.003, Feb. 2013.
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