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Comet Nucleus Tour

Phase: Past

Launch Date: July 03, 2002

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CONTOUR's goals were to improve our knowledge of key characteristics of comet nuclei and to assess their diversity, by making close approaches to at least two comets. CONTOUR was launched on July 3, 2002 July. When CONTOUR was to have fired its onboard motor to depart from Earth orbit on August 15, contact with the spacecraft was lost. Telescopic surveys were used to locate three objects near the spacecraft's predicted position assuming the firing had been partially successful. Alternate but less likely causes include catastrophic failure of the solid rocket motor, collision with space debris, or loss of dynamic control of the spacecraft.

CONTOUR was to perform imaging of the comet nuclei at resolutions of 4m, as well as perform spectral mapping of the nuclei at resolutions of 100-200 m. These observations were to be linked with imaging, spectroscopic, and thermal data obtained from Earth-based or Earth-orbital telescopes, as the encounters occur at times ideal for remote sensing observations from Earth. In addition, detailed compositional data on both gas and dust in the near-nucleus environment will be performed.

Comets are the most pristine, primitive bodies in the solar system, and it is expected that they retain more evidence of the processes that took place when the solar system formed than do subsequently-evolved larger bodies. The complex organic molecules present in comet nuclei may have been the original source of organics on Earth from which life formed, and examination of comet nuclei would yield information on how these molecules were produced.

The Neutral Gas and Ion Mass Spectrometer (NGIMS) was to measure the abundance and isotope ratios for many neutral and ion species in the coma of each comet during the flyby. These measurements together with data from the dust experiment will contribute to the understanding of the chemical composition of the nucleus itself and allow differences between the comets to be studied.

CONTOUR was scheduled for fly-bys of Comet Encke, Comet Schwassmann-Wachmann-3 and Comet d'Arrest.