urn:esa:psa:context:instrument:rl.civa 1.0 1.16.0.0 Product_Context 2021-06-15 1.0 Migrated from PDS3 catalog file. urn:esa:psa:context:instrument_host:spacecraft.rl instrument_to_instrument_host 10.1007/s11214-006-9135-5 Bibring, J.P et al., CIVA, Space Sci. Rev., 128(1-4), 397-412, Feb. 2007. Reference to the instrument paper. CIVA - Cometary Infrared and Visible Analyzer Imager Camera Imaging Spectrometer Infrared Spectrometer not applicable not applicable Instrument Overview =================== Integrated set of imaging instruments, designed to characterize the 360 degrees panorama (CIVA-P) as seen from the Rosetta Lander Philae, and to study surface and subsurface samples (CIVA-M). CIVA-P is a panoramic stereo camera, while CIVA-M is an optical microscope coupled to a near infrared microscopic hyperspectral imager Scientific Objectives ===================== stereoscopic imaging of the site surrounding the Lander (CIVA-P), and by optical imaging and infrared spectral imaging of surface and subsurface samples of the cometary nucleus, at a microscopic scale (CIVA-M) Calibration =========== Following calibration functions are applied to the CIVA-P images, at IAS level: Non-linearity correction The TH7888A detector presents a strong deviation from linearity when the signal is higher than ~ 80% of the saturation level. This saturation level depends on the camera, on the gain setting and on the temperature of the detector. A linearity correction transformation which includes the subtraction of the offest has therefore been applied to level 1 CIVA images which reach levels close to saturation (CIVA 1, CIVA 2, CIVA 3 and CIVA4). The linearity files providing the actual DN level from the measured DN level (1024 floating point values) are civa1scale.txt, civa2scale.txt, civa3scale.txt, civa4scale.txt. The offset was evaluated as 18.4 DN, 19 DN, 13 DN and 20.9 DN for these four cameras. Cameras CIVA 5, CIVA 6 and CIVA 7 have low DN values, hence the corrected values correspond to the subtraction of an offset of 17.8 DN, 20.5 DN and 14.5 DN for CIVA 5, CIVA 6 and CIVA 7 respectively. Regions of images from the CIVA 1, CIVA 2, CIVA 3 and CIVA 4 cameras are saturated. This situation is indicated in the image file by a value of the recovered DN equal to the maximum floating value of the transformation table provided in 'civaNscale.txt' (N=1 to 4). Operational Considerations ========================== CIVA-P will be operated to take one stereo image of the Orbiter jus after release of Philae, to be used as calibration for the on-comet images. Then, immediately after touch-down, a full panorama of the landing site, with a partial stereoscopic coverage, will be taken by CIVA-P, and immediately transmitted to the Earth for quick look data reduction. This first panorama will be key to assess the landing conditions, and to declare secure the planned Philae sequence of operations. Follow-ons partial or global panoramas could be acquired either to monitor changes with solar illumination and/or cometary activity, to increase the stereoscopic coverage, and to image after their deployment Philae systems and sensors. CIVA-M will be turned on after all samplings (surface and subsurface) by SD2. It will consist in sequences of calibration (by imaging an oven with a calibration target), imaging of ovens prior to be filled, and after being filled by SD2 with cometary samples. CIVA-M/V will image each oven in three colors, while CIVA-M/I will acquire a complete 3D (x,y,lambda) image cube of them. After compression and storage in the IME mass memory, the data will be transferred to CDMS for downlink. Electronics =========== This Imaging Main Electronics (IME) is a facility, developed under the co-responsibility of IWP/DLR and IAS, for both ROLIS and CIVA: they share a common I/F with the Lander, for both the power subsystem and the Central Data Management System (CDMS). Thus the IME includes the CIVA-Central Electronics (CIVA-CE), mainly based on a dedicated CDPU (Command and Data Processing Unit); it is equipped with a 16 Mbytes mass memory. The CIVA-CDPU (Command and Data Processing Unit), developed by IAS, has the following functions: on/off power control; camera program uploading; camera heads check out; command reception (from ROLIS-DPU) and management; CIVA payload sequencing; status monitoring; image acquisition; integration time optimization; image compression (using wavelet based software); error encoding and data formatting. It consists of a TEMIC TSC21020 processor, 2 Kword PROMs for boot sequence, 512 Kbyte EEPROM for application program and parameters storage, 128 KWord Fast SRAM for application program, 128 KWord Fast SRAM for application data and 6 Mbyte SRAM for 2 images data (1024x1024 pixels) storage/processing. The CDPU electronics is integrated into a 3D-packaged cube which is implemented into the IME. The CIVA-CE includes two more electrical boards: one is dedicated to the IR detector, and the second to the CIVA peripherics. Location ======== CIVA-P is constituted of 7 identical miniaturized cameras, implemented as 5 single cameras and one stereoscopic pair of two co-aligned ones, thus filling the 360 deg. panoramic field of view by six contiguous and overlapping FOV of 70 deg. each, 60 deg. apart one from the next. CIVA-M is constituted of a visible microscope, CIVA-M/V and a near infrared hyperspectral imager CIVA-M/I. CIVA-M/V and CIVA-M/I are mounted on the Philae base-plate (balcony), close to the drill and sample distribution system (SD2). They will image and analyse the samples (from a distance of 13.0 mm) whenever they will be deposited within containers (Mid Temperature Ovens), mounted on a rotating carousel, and closed by a sapphire window transparent in both the Visible and the near IR. Operational Modes ================= CIVA can be basically operated in 4 modes: - Software upload. - Pannoramic imaging - Visible Microscopic imaging - Hyperspectral Microscopic imaging Subsystems ========== The sub-systems are described in Bibring et al, 2007. Measured Parameters =================== Stereoscopic imaging of the site surrounding the Lander (CIVA-P), and optical imaging and infrared spectral imaging of surface and subsurface samples of the cometary nucleus, at a microscopic scale (CIVA-M). CIVA will analyse cometary material from micron size particles to meter size features: 7 micrometres to a few mm with the microscope, 1 mm to meters with the panoramic cameras.