urn:nasa:pds:context:instrument:lidar.hay 1.0 1.7.0.0 Product_Context 2016-10-01 1.0 extracted metadata from PDS3 catalog and modified to comply with PDS4 Information Model urn:nasa:pds:context:instrument_host:spacecraft.hay::1.0 instrument_to_instrument_host Abe, S., T. Mukai, N. Hirata, O.S. Barnouin-Jha, A.F. Cheng, H. Demura, R.W. Gaskell, T. Hashimoto, K. Hiraoka, T. Honda, T. Kubota, M. Matsuoka, T. Mizuno, R. Nakamura, D.J. Scheeres, and M. Yoshikawa, Mass and Local Topography Measurements of Itokawa by Hayabusa, Science, 312, 1344-1347, 2006. reference.ABEETAL2006B Mukai, T., H. Araki, T. Mizuno, N. Hatanaka, A.M. Nakamura, A. Kamei, H. Nakayama and A. Cheng, Detection of mass, shape and surface roughness of target asteroid of MUSES-C by LIDAR, Adv. Space Res., 29, 1231-1235, 2002. reference.MUKAIETAL2002 Mukai, T., A.M. Nakamura and T. Sakai, Asteroidal surface studies by laboratory light scattering and LIDAR on HAYABUSA, Adv. Space Res., 38, 138-141, 2006. reference.MUKAIETAL2006 Mukai, T., S. Abe, N. Hirata, R. Nakamura, O.S. Barnouin-Jha, and 11 others, An overview of the LIDAR observations of asteroid 25143 Itokawa. Advances in Space Research 40, 187-192, 2007. reference.MUKAIETAL2007 LIGHT DETECTION AND RANGING INSTRUMENT Altimeter not applicable not applicable Instrument Overview =================== The principal components of LIDAR are a diode-pumped, Nd:YAG laser transmitter that emits 1.064 micrometer wavelength laser pulses, a 0.126 m diameter telescope, a silicon avalanche photodiode detector, and a time interval unit with 14 nsec resolution. During the long Home Position phase (~7km from Itokawa) of the misson, LIDAR provides measurements of the topography of Itokawa within approximately 12x4.9 m footprints. The center-to-center along-track footprint spacing is highly variable throughout the mission. Range measurements, with an effective resolution of 50 cm, are converted to profiles of asteroid radius and topographic height after correction for orbit and pointing errors. Shot locations are determined to within 10 m in the along-track and across-track directions. The current radial inaccuracies of the LIDAR data do not permit the generation of global grids of the surface of Itokawa. Additional refinements are still required. LIDAR was designed, built and tested at the Institute of Space and Astronautical Science (ISAS) in Sagamihara, Japan part of the Japan Aerospace Exploration Agency. LIDAR Science Objectives ======================= The primary LIDAR objective was to determine the distance between the HAYABUSA spacecraft and Itokawa to ensure a safe touch and go sampling of the asteroid. The LIDAR was key for obtain a reliable shape model of the surface of the asteroid, required for establishing its volume and mass. In addition, it was found suitable for addressing problems in geology and geophysics [see ABEETAL2006,MUKAIETAL2007]. Instrument Specifications ========================= The following table summarizes LIDAR characteristics. Parameter Value Unit ---------------------------------------------------------------- Physical Characteristics Volume 0.0137 m^3 Mass 3.56 kg Power (TOTAL) 22.00 W Laser Transmitter Laser type Q-switched, diode-pumped Nd:YAG* Wavelength 1.064 micrometer Laser energy 10 mJ pulse^-1 Laser power consumption 17 W Pulse width 14 ns (FWHM**) Pulse repetition rate 1 sec^-1 Beam divergence 1.7x0.7 mrad Altimeter Receiver Telescope type Cassegrain Mirror composition SiC Telescope diameter 0.126 m Detector type Silicon avalanche photodiode (Si APD) Receiver Electronics Receiver type Filtered peak trigger Time resolution 3.0 nsec Range resolution 0.5 m Range accuracy (@50km) 10.0 m Measurements Footprint size (@ 7 km) 12.0x4.9 m * Nd:YAG is neodymium-doped yttrium aluminum garnet. ** FWHM is full width at half maximum. ---------------------------------------------------------------- Operational Considerations ========================== The LIDAR instrument measures the round-trip time of flight of infrared laser pulses transmitted from the HAYABUSA spacecraft to the surface of Itokawa. The instrument operates in a single autonomous mode, in which it produces ranging measurements. Surface topography estimates can be derived from these data, given appropriate corrections for the position and attitude of the spacecraft. LIDAR's transmitter is a Q-switched, Nd:YAG laser oscillator. The Q-switch controls the emission of the laser, and Nd:YAG refers to the composition of the material that is optically excited to produce laser action: Neodymium-doped Yttrium Aluminum Garnet. The laser emits a 14-ns-wide (full width at half the maximum pulse amplitude, FWHM) pulses at 1.064 micrometers. The pulse repetition rate is 1 Hz, and the pulse energy was 10 mJ durign the entire peroid of operation. The laser consumed 17 W when operating, and it functioned without flaws for the entire 3 month period of the encounter with Itokawa. For additional information on the HAYABUSA LIDAR and its usage see MUKAIETAL2002 and MUKAIETAL2006. For a summary of some of the results obtained with the LIDAR see ABEETAL2006. References ========== Abe, S., T. Mukai, N. Hirata, O.S. Barnouin-Jha, A.F. Cheng, H. Demura, R.W. Gaskell, T. Hashimoto, K. Hiraoka, T. Honda, T. Kubota, M. Matsuoka, T. Mizuno, R. Nakamura, D.J. Scheeres, and M. Yoshikawa, Mass and Local Topography Measurements of Itokawa by Hayabusa, Science, 312, 1344-1347, 2006. [ABEETAL2006B] Mukai, T., H. Araki, T. Mizuno, N. Hatanaka, A.M. Nakamura, A. Kamei, H. Nakayama and A. Cheng, Detection of mass, shape and surface roughness of target asteroid of MUSES-C by LIDAR, Adv. Space Res., 29,1231-1235, 2002.[MUKAIETAL2002] Mukai, T., A.M. Nakamura and T. Sakai, Asteroidal surface studies by laboratory light scattering and LIDAR on Hayabusa, Adv. Space Res., 38, 138-141, 2006. [MUKAIETAL2006] Mukai, T., S. Abe, N. Hirata, R. Nakamura, O.S. Barnouin-Jha, and 11 others, An overview of the LIDAR observations of asteroid 25143 Itokawa. Advances in Space Research 40, 187-192, 2007. [MUKAIETAL2007]