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Framing Camera

NSSDCA ID: 2007-043A-01

Mission Name: Dawn
Principal Investigator:Dr. Horst Uwe Keller

Description

The Dawn mission will carry two identical framing cameras. The cameras are involved in many of the scientific objectives of the mission. The primary science goal for the cameras is to return data mapping the surfaces which will help in characterizing the geologic history and evolution of the asteroids. The images will be used to characterize the size and shape, surface morphology, surface texture and regolith features. Multispectral images will help determine the geologic makeup of the asteroids.

The framing camera consists of a camera head and associated electronics. The camera head is cylindrical and is capped by a stray light baffle which shades the pupil from reflections from the spacecraft and a recloseable cover to protect the optics. Each camera uses f:1/8 radiation hardened refractive optics with a focal length of 150 mm to focus the incoming light through a filter wheel onto a 1024 x 1024 frame transfer CCD. The field of view is 5.5 x 5.5 degrees with a resolution of 9.3 m/pixel at a distance of 100 km. The filter wheel has 8 positions, a clear filter from 450 - 950 nm and seven filters centered at 430, 540, 650, 750, 830, 920, and 980 nm. All seven filters have a FWHM of 40 nm except the 980 nm filter which has a FWHM of 80 nm. The sensitivity of each filter is sufficient to give a signal to noise ratio of 100 for exposures of 100 ms to 1 s of the asteroid surfaces. Each camera head has a mass of 2.5 kg and uses 1.8 W. The camera readout rate is 1.6 s for a 1024 x 1024 frame, with a minimum exposure time of 1 ms. Each camera has independent readout electronics with data processing units that compress the images in lossless or lossy formats. Each framing camera system has a mass of roughly 5 kg and consumes about 12 W.

Alternate Names

  • Dawn/FramingCamera

Facts in Brief

Mass: 10 kg
Power (avg): 24 W

Funding Agency

  • Deutsche Forschunganstalt fuer Luft- und Raumfahrt (DLR, nee DFVLR) (Germany)

Discipline

  • Planetary Science: Small Bodies

Additional Information

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

 

Personnel

NameRoleOriginal AffiliationE-mail
Dr. Horst Uwe KellerPrincipal InvestigatorMax-Planck-Institut fur Aeronomiekeller@linmpi.mpg.de
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