The spacecraft consists of a 350 kg copper impactor attached to a flybybus with a combined launch mass of 1020 kg. The spacecraft is abox-shaped honeycombed aluminum framework with a flat rectangular Whipple debris shieldmounted on one side to protect components during comet close approach. Mounted on theframework are one high- and one medium-resolution instrument, each of which consists of animaging camera and an infrared spectrometer which will be used to observe this ejected iceand dust, much of which will be exposed to space for the first time in over 4 billionyears. The medium resolution camera has a field of view (FOV) of 0.587 degrees and aresolution of 7 m/pixel at 700 km distance and is used for navigation and context images.The high resolution camera has a FOV of 0.118 degrees and a resolution of 1.4 m/pixel at700 km. The infrared spectrometers cover the range from 1.05 to 4.8 micrometers with FOVof 0.29 degrees (hi-res) and 1.45 degrees (lo-res). The total flyby bus instrument payloadhas a mass of 90 kg.
The Deep Impact
The flyby spacecraft measures approximately 3.2 m x 1.7 m x 2.3 m, is three-axisstabilized and uses a hydrazine propulsion system. Communications with the ground from theflyby bus are via X-band (8.000 MHz) through a 1 meter diameter parabolic dish antennamounted on a 2-axis gimbal and via S-band between the impactor and flyby spacecraft. Themaximum data rate will be 400 kbps. Power of 620 W at the encounter is provided by a 7.5square meter solar array and stored in a small NiH2 battery.
The projectile is made of copper so it is easily identifiable in the spectra afterthe projectile is largely vaporized and mixed in with the comet ejecta on impact. Theimpactor is equipped with an Impactor Targeting Sensor, an imager which provides knowledgefor autonomous control and targeting, and a cold-gas attitude control system. The totalbudget for the mission is $240 million.
Deep Impact was launched on 12 January 2005 on a Delta-7925. After entering a heliocentric orbitthe spacecraft flew by Moon in January 2005. During this flyby the Moon was used to testthe targeting system performance without releasing the impactor. The spacecraft was about880,000 km from comet P/Tempel 1 on 3 July 2005 moving at a velocity of 10.2 km/s relativeto the comet. The projectile was released at this point and shortly after release theflyby spacecraft executed a maneuver to slow down relative to the impactor at 120 m/s. On4 July the impactor struck the sunlit side of the comet nucleus 24 hours after release. Atthe 10.2 km/s velocity, the impactor formed a crater roughly 25 meters deep and 100 meterswide, ejecting material from the interior of the nucleus into space and vaporizing theimpactor and much of the ejecta. The flyby spacecraft was approximately 10,000 km away atthe time of impact and began imaging 60 seconds before impact. At 600 seconds after impactthe spacecraft was about 4000 km from the nucleus and observations of the crater began andcontinued until closest approach to the nucleus at a distance of about 500 km. At 961seconds after impact imaging ended when the spacecraft reorients to cross the inner coma.At 1270 seconds the crossing of the inner coma was complete and the spacecraft orienteditself to look back at the comet. At 3000 seconds the spacecraft began playback of data toEarth. The comet and spacecraft were about 0.89 AU from Earth and 1.5 AU from the Sunduring the encounter. Real time return of selected impactor images and flyby images andspectra were returned to Earth during the encounter. Primary data return was to be overthe first day after encounter, with a 28 day supplemental data return period. Earth-basedobservatories also studied the impact. The spacecraft ranged over a distance of 0.93 to1.56 AU from the Sun during the mission.
Feature Papers represent the most advanced research with significant potential for high impact in the field. FeaturePapers are submitted upon individual invitation or recommendation by the scientific editors and undergo peer reviewprior to publication.
With a design developed from industrial professionals, the Deep Impact Cut360 has the comfort and dexterity perfectly balanced with heavy industrial protection needs. Ultra-flexible goatskin leather gloves have evolved with hidden cut and puncture protection layers that can stop injuries pro-actively. Flexible impact protection keeps high incidence areas of injury protected without slowing you down. Classic ranch cuff keeps hands from getting too hot on long workdays.
The Deep Impact spacecraft has completed its first steps in exploring a comet's interior by creating a crater with an impactor spacecraft, allowing the mother spacecraft to look deep inside the comet during a fly-by immediately afterwards.
New data and results on Tempel 1 and the impact will continue to be received in the next hours and days. Follow us while we continue to cover one of the world's largest astronomical observation campaigns, which includes ESA and NASA spacecraft, European observatories and many co-operating organisations around the world.
Deep Impact is the eighth mission in the Discovery Program, designed to investigate the interior of a cometary nucleus. The two-piece spacecraft was launched on 12 January 2005 and successfully encountered the comet 9P/Tempel 1 on 4 July 2005. About 24 hours before the spacecraft encountered the comet, the flyby spacecraft released the impactor spacecraft, a 1/2-ton copper projectile equipped with a visible CCD, to hit the comet's nucleus. This impact ejected material from the interior of the comet out into space and produced a crater that is believed to be at least 100-m in diameter. The flyby spacecraft and its three instruments survived the encounter with Tempel 1, and resumed operations from October 2007 to February 2011 for the EPOXI mission.
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