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The ''CO''met ''N''ucleus ''TOUR'' (CONTOUR) was a NASA Discovery-class space probe that failed shortly after its July 2002 launch. It had as its primary objective close flybys of two comet nuclei with the possibility of a flyby of a third known comet or an as-yet-undiscovered comet. The two comets scheduled to be visited were Encke and Schwassmann-Wachmann-3, and the third target was d'Arrest. It was hoped that a new comet would have been discovered in the inner Solar System between 2006 and 2008, in which case the spacecraft trajectory would have been changed if possible to rendezvous with the new comet. Scientific objectives included imaging the nuclei at resolutions of up to , performing spectral mapping of the nuclei at resolutions of up to , and obtaining detailed compositional data on gas and dust in the near-nucleus environment, with the goal of improving knowledge of the characteristics of comet nuclei. After the solid rocket motor intended to inject the spacecraft into solar orbit was ignited on August 15, 2002, contact with the probe could not be re-established. Ground-based telescopes later found three objects along the course of the satellite, leading to the speculation that it had disintegrated. Attempts to contact the probe were ended on December 20, 2002. The probe thus accomplished none of its primary scientific objectives, but did prove some spaceflight technologies, such as the APL-developed non-coherent spacecraft navigation technique, which was later used on the New Horizons spacecraft. ==Spacecraft design== The ''CONTOUR'' spacecraft had a total fueled mass of 775 kg, including 70 kg of hydrazine fuel and a Star 30BP booster with a mass of 377 kg. Power was provided by a body-mounted solar array designed for operation at distances between 0.75 and 1.5 AU from the Sun. It was three-axis stabilized for encounters and spin-stabilized during cruise mode between encounters. COUNTOUR's Command/Data-handling and Guidance/Control computers both used the Mongoose-V microprocessor. Communications were through a fixed 0.45 m diameter high-gain antenna designed to support data rates greater than 100 kbit/s at encounters. Data and images were stored on two 3.3 Gbit solid-state recorders with a capacity of 600 images. The spacecraft was equipped with four primary science instruments: the Contour Remote Imager/Spectrograph (CRISP), the Contour Aft Imager (CAI), the Dust Analyzer (CIDA), and the Neutral Gas Ion Mass Spectrometer (NGIMS). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「CONTOUR」の詳細全文を読む スポンサード リンク
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