Imaging Technique of the Imaging Technique of the DISR Camera on the Huygens DISR Camera on the Huygens

LanderLander

J.R. KrammJ.R. Kramm11, H.U. Keller, H.U. Keller11, R. Bredthauer, R. Bredthauer22 and M. and M. TomaskoTomasko33

1 1 Max-Planck-Institut für SonnensystemforschungMax-Planck-Institut für Sonnensystemforschung

Katlenburg-Lindau, GermanyKatlenburg-Lindau, Germany

2 2 Semiconductor Technology Associates, Inc.Semiconductor Technology Associates, Inc.San Juan Capistrano, CASan Juan Capistrano, CA

3 3 Lunear and Planetary Laboratory,Lunear and Planetary Laboratory,University of Arizona, Tucson, AZUniversity of Arizona, Tucson, AZ

MPS, June 20, 2005

Descent Imager/ Spectral Radiometer Descent Imager/ Spectral Radiometer (DISR)(DISR)

Instrument Consortium Instrument Consortium

Scientific ObjectivesScientific Objectives

• Medium and high-resolutions Imaging of the surface of TitanMedium and high-resolutions Imaging of the surface of Titan• Imaging of clouds and haze at TitanImaging of clouds and haze at Titan• Spectral investigations, 350 – 1700 nmSpectral investigations, 350 – 1700 nm• Solar Aureole, 500 and 935 nm, horiz. and vertical polarizationSolar Aureole, 500 and 935 nm, horiz. and vertical polarization

Instrument responsibility:Instrument responsibility:Manufacturing contractor:Manufacturing contractor:CCD Imager & electronics:CCD Imager & electronics:

CCD contractor:CCD contractor:H/W compression:H/W compression:Infrared detector:Infrared detector:

LPL, Tucson, AZLPL, Tucson, AZLockheed Martin, Denver, COLockheed Martin, Denver, COMax-Planck-Institut, GermanyMax-Planck-Institut, GermanyLoral, Newport Beach, CALoral, Newport Beach, CAUniv. Braunschweig, GermanyUniv. Braunschweig, GermanyObservatoire de Paris, FranceObservatoire de Paris, France

DISR Instrument DISR Instrument CharacteristicsCharacteristics

14 optical apertures total14 optical apertures total 9 optical apertures to 1 CCD detector9 optical apertures to 1 CCD detector 1.1 Watt for the CCD, 512 x 256 pixels1.1 Watt for the CCD, 512 x 256 pixels Date rate:Date rate:8 kbit/s, ~ 1 bit per pixel8 kbit/s, ~ 1 bit per pixel 6 years for design, production and calibr.6 years for design, production and calibr. 7.5 years travel time to Titan, 1997-20057.5 years travel time to Titan, 1997-2005 150 min total operation time envisaged150 min total operation time envisaged

220 min operation completed220 min operation completed 600 Images acquired + Spectra etc.600 Images acquired + Spectra etc.

DISR InstrumentDISR Instrumenton the Huygens Probeon the Huygens Probe

The Loral Max-Planck CCD The Loral Max-Planck CCD

ApproachApproach

• Dedicated buried channel design for DISR / Max-PlanckDedicated buried channel design for DISR / Max-Planck• Front side illuminated Frame Transfer CCDFront side illuminated Frame Transfer CCD• 2 phase MPP clocking2 phase MPP clocking• Image and Memory sections 256 rows, 512 (+8 dark) columnsImage and Memory sections 256 rows, 512 (+8 dark) columns• Gated lateral anti-blooming, also electronic shutterGated lateral anti-blooming, also electronic shutter• 23 23 μμ pixel pitch pixel pitch (17 (17μμ x 23 x 23μμ active area) active area)• Pixel capacity 150,000 Pixel capacity 150,000 e‾e‾ (100,000 e‾ used)(100,000 e‾ used)• QE up to 50 %,QE up to 50 %, CTE = .999 999 CTE = .999 999• Line transfer 2 Line transfer 2 μμs/lines/line low image smear on shift low image smear on shift• Single stage output amplifier,Single stage output amplifier, 5- 8 5- 8 electronselectrons @ 70 kHz

• OP16 JFET preamp on Sensor Head Board - (MPS)OP16 JFET preamp on Sensor Head Board - (MPS)• Electronics Assembly holds CDS, clock drivers and 12 bit ADCElectronics Assembly holds CDS, clock drivers and 12 bit ADC• CCD shielded by 4 mm tungsten to prevent < 62 MeV protonsCCD shielded by 4 mm tungsten to prevent < 62 MeV protons

• DISR CCD was also used for Imager for Mars Pathfinder (IMP)DISR CCD was also used for Imager for Mars Pathfinder (IMP)and 2x for Mars Polar Lander (Stereo and Robotic Arm Camera)and 2x for Mars Polar Lander (Stereo and Robotic Arm Camera)

DISR CCD LayoutDISR CCD Layout

The DISR Optical System with CCDThe DISR Optical System with CCD

DISR Camera HeadDISR Camera Head

DISR Bias FramesDISR Bias Frames

Imager Bias Frames, 0 ms exposure, 260 K, andMRI Column Amplitude from 1994, 2000, 2005

Dark charge increase approx. 60x upon protonirradiation from a plutonium heater 10 cm apartfrom the Sensor Head (1997-2005).

CCDCCD Operation Temperature Operation Temperature Profile Profile

and Dark Charge Temperature and Dark Charge Temperature ScaleScale

DISR In-flight Flat Field MatricesDISR In-flight Flat Field Matrices

In-flight Irradiation EffectsIn-flight Irradiation Effects

In-flight proton irradiation from a nuclearheater located close to the CCD (~10 cm)

Resulting effects:

• Perfect thermal balance established• Dark charge increase about 60x with minor effects

(low temperature, short exposure times, 7 to 50 ms)• CTE degradation