Concepção artística mostra a Deep Impact e a Impactor ao fundo
Inspirando-se no filme americano Impacto Profundo, a NASA chamou de Deep Impact a esta sonda espacial. O objetivo da missão não tripulada norte-americana Deep Impact, ou Impacto Profundo, da NASA, sob os cuidados do Laboratório de Jato-propulsão - JPL, foi o de lançar um impactador contra o cometa 9P/Tempel 1 ou simplesmente Tempel 1 que circula entre as órbitas de Marte e Júpiter, observar a explosão e a partir dela analisar os componentes químicos e físicos internos do cometa.
A sonda Deep Impact foi lançada em 12 de janeiro de 2005 pelo foguete Delta II (modelo 2925), do Cabo Canaveral, Estados Unidos. O impacto da sonda com o cometa ocorreu em 4 de julho de 2005.
O cometa escolhido pertence a uma classe de cometas que são comuns do sistema solar e o impacto não deverá causar uma significativa mudança na trajetória do cometa.
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The spacecraft
consists of two main sections, the 370-kg (815-lb) copper-core "Smart
Impactor" that impacted the comet, and the "Flyby" section, which imaged
the comet from a safe distance during the encounter with Tempel 1.
The Flyby spacecraft is about 3.2 meters (10.5 ft) long, 1.7 meters (5.6 ft) wide and 2.3 meters (7.5 ft) high. It includes two solar panels, a debris shield, and several science instruments for imaging, infrared spectroscopy,
and optical navigation to its destination near the comet. The
spacecraft also carried two cameras, the High Resolution Imager (HRI),
and the Medium Resolution Imager (MRI). The HRI is an imaging device
that combines a visible-light camera with a filter wheel, and an imaging
infrared spectrometer
called the "Spectral Imaging Module" or SIM that operates on a spectral
band from 1.05 to 4.8 micrometres. It has been optimized for observing
the comet's nucleus. The MRI is the backup device, and was used
primarily for navigation during the final 10-day approach. It also has a
filter wheel, with a slightly different set of filters.
The Impactor section of the spacecraft contains an instrument that is
optically identical to the MRI, called the Impactor Targeting Sensor
(ITS), but without the filter wheel. Its dual purpose was to sense the
Impactor's trajectory, which could then be adjusted up to four times
between release and impact, and to image the comet from close range. As
the Impactor neared the comet's surface, this camera took
high-resolution pictures of the nucleus (as good as 0.2 metre [7.9 in]
per pixel)
that were transmitted in real-time to the Flyby spacecraft before it
and the Impactor were destroyed. The final image taken by the impactor
was snapped only 3.7 seconds before impact.
The impactor's payload, dubbed the "Cratering Mass", was 100% copper
(impactor 49% copper by mass) to reduce debris interfering with
scientific measurements of the impact. Since copper was not expected to
be found on a comet, scientists could eliminate copper from the
spectrometer reading. Instead of using explosives, it was also cheaper to use copper as the payload.
The name of the mission is shared with the 1998 Deep Impact
film, in which a comet strikes the Earth. This is coincidental,
however, as the scientists behind the mission and the creators of the
film devised the name independently of each other at around the same
time.
Filme do High Resolution Imager (HRI) na sonda Deep Impact do impacto
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