PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = " 2006-12-27 SOC:Carcich Initial version; 2008-08-25 SOC:Carcich Changed iNSTRUMENT_DESC spacing and indentation per PDS Standards Reference recommendations. " RECORD_TYPE = STREAM OBJECT = INSTRUMENT INSTRUMENT_HOST_ID = "NH" INSTRUMENT_ID = "LORRI" OBJECT = INSTRUMENT_INFORMATION INSTRUMENT_NAME = "LONG RANGE RECONNAISSANCE IMAGER" INSTRUMENT_TYPE = "IMAGER" INSTRUMENT_DESC = " ######################################################################## ######################################################################## REQUIRED READING: - Cheng et al. (2008) [CHENGETAL2008] - Conard et al. (2005) [CONARDETAL2005] ######################################################################## ######################################################################## The LORRI description was was adapted from [CONARDETAL2005], [CHENGETAL2008], and the New Horizons website. INSTRUMENT OVERVIEW =================== The LOng-Range Reconnaissance Imager (LORRI) is an instrument that was designed, fabricated, and qualified for the New Horizons mission to the outermost planet Pluto, its giant satellite Charon, and the Kuiper Belt, which is the vast belt of icy bodies extending roughly from Neptune's orbit out to 50 astronomical units (AU). New Horizons launched in January 2006 as the inaugural mission in NASA's New Frontiers program. SPECIFICATIONS -------------- NAME: LORRI (Long-Range Reconnaissance Imager) DESCRIPTION: High-resolution telescope PRINCIPAL INVESTIGATOR: Andy Cheng, APL WAVELENGTH RANGE: 350 - 850nm FIELD OF VIEW: 5.06 x 5.06 milliradians (0.29 x 0.29 degrees) ANGULAR RESOLUTION: 0.00494 milliradians, unbinned WAVELENGTH RESOLUTION: N/A PRIMARY DATA FORMAT(S): 1) 1024x1024 2-D pixel array (unbinned) 2) 256x256 2-D pixel array (4x4 binned) PRIMARY MEASURED QUANTITIES: 1) Raw data: per-pixel brightnesses as Data Numbers (DNs) 2) Calibrated data: per-pixel brightnesses as radiances DESCRIPTION ----------- LORRI is a narrow angle (field of view=0.29 deg), high resolution (instantaneous field of view = 4.94 urad), Ritchey-Chretien telescope with a 20.8 cm diameter primary mirror, a focal length of 263 cm, and a three lens field-flattening assembly. A 1024 x 1024 pixel (optically active region), back-thinned, backside-illuminated charge-coupled device (CCD) detector (model CCD 47-20 from E2V Technologies) is located at the telescope focal plane and is operated in standard frame-transfer mode. LORRI does not have any color filters; it provides panchromatic imaging over a wide bandpass that extends approximately from 350 nm to 850 nm. A unique aspect of LORRI is the extreme thermal environment, as the instrument is situated inside a near room temperature spacecraft, while pointing primarily at cold space. This environment forced the use of a silicon carbide optical system, which is designed to maintain focus over the operating temperature range without a focus adjustment mechanism. Another challenging aspect of the design is that the spacecraft is thruster-stabilized (no reaction wheels), which places stringent limits on the available exposure time and the optical throughput needed to accomplish the high-resolution observations required. LORRI was designed and fabricated by a combined effort of The Johns Hopkins University Applied Physics Laboratory (APL) and SSG Precision Optronics Incorporated (SSG). LORRI has four subassemblies in close proximity connected by electrical harnesses. These are the optical telescope assembly (OTA), the aperture cover door, the associated support electronics (ASE), and the focal plane unit (FPU). Except for the door, all are mounted inside the spacecraft on its central deck; the door is mounted to an external spacecraft panel. LORRI is electronically shuttered, with no moving parts aside from the cover door. The ASE implements all electrical interfaces between LORRI and the spacecraft except for the door control, several spacecraft thermistors, and two decontamination heaters. [CONARDETAL2005] gives a detailed description of LORRI design, manufacture and test. Scientific Objectives ===================== Hemispheric panchromatic maps of Pluto and Charon at best resolution exceeding 0.5 km/pixel. Search for atmospheric haze at a vertical resolution <5 km Long time base of observations, extending over 10 to 12 Pluto rotations Panchromatic maps of the far-side hemisphere High resolution panchromatic maps of the terminator region Panchromatic, wide phase angle coverage of Pluto, Charon, Nix, and Hydra Panchromatic stereo images of Pluto, Charon, Nix, and Hydra Orbital parameters, bulk parameters of Pluto, Charon, Nix, and Hydra Search for satellites and rings Calibration =========== See [CHENGETAL2008] Detectors ========= Frame transfer CCD. See [CHENGETAL2008] for details. Electronics =========== LORRI electronics consist of the ASE and FPU. The ASE contains three printed circuit cards. These are the low voltage power supply (LVPS), the event processor unit (EPU), and the imager input/output (IM I/O). The ASE is the primary interface between the spacecraft and the FPU, which mounts and controls the CCD. Additional information can be found in [CONARDETAL2005]. Filters ======= None. Optics ====== The LORRI OTA is a Ritchey-Chretien design, with high system throughput required because of the short allowed exposure time and low light level at Pluto. The complete LORRI OTA design was evaluated with a computer-aided design model including stray light analysis. Specular reflections and bidirectional reflectance distribution functions of the Aeroglaze Z-306 black paint, primary and secondary mirrors, field group optics and focal plane were included in the model. The primary and secondary baffle tubes were sized to minimize obscuration and suppress direct paths to the FPA's active area. The telescope magnification and obscuration were balanced, affecting the optical sensitivity and MTF, respectively. Out-of-field stray light was evaluated by generating point source transmittance curves with angular scans across the boresight in two orthogonal directions (-70 degrees to +70 degrees for each scan) to search for any obscured paths with unacceptable amplitude. See [CHENGETAL2008] for more details. Operational Modes ================= LORRI high-rate image data telemetry APID definitions C&DH binning APID side mode compression type 0x630 1 1x1 lossless 0x631 1 1x1 packetized 0x632 1 1x1 lossy 0x633 1 4x4 lossless 0x634 1 4x4 packetized 0x635 1 4x4 lossy 0x636 2 1x1 lossless 0x637 2 1x1 packetized 0x638 2 1x1 lossy 0x639 2 4x4 lossless 0x63A 2 4x4 packetized 0x63B 2 4x4 lossy Measured Parameters =================== Radiance. " END_OBJECT = INSTRUMENT_INFORMATION OBJECT = INSTRUMENT_REFERENCE_INFO REFERENCE_KEY_ID = "CHENGETAL2008" END_OBJECT = INSTRUMENT_REFERENCE_INFO OBJECT = INSTRUMENT_REFERENCE_INFO REFERENCE_KEY_ID = "MORGANETAL2005" END_OBJECT = INSTRUMENT_REFERENCE_INFO OBJECT = INSTRUMENT_REFERENCE_INFO REFERENCE_KEY_ID = "CONARDETAL2005" END_OBJECT = INSTRUMENT_REFERENCE_INFO END_OBJECT = INSTRUMENT END