Data Set Information
DATA_SET_NAME HAYABUSA NIRS CALIBRATED SPECTRA V1.0
DATA_SET_ID HAY-A-NIRS-3-NIRSCAL-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : The Hayabusa spacecraft launched on May 9, 2003, performed an Earth flyby on May 19, 2004, and reached the asteroid 25143 Itokawa in September 2005, spending September through November 2005 at the asteroid. During the mission the Hayabusa Near-Infrared Spectrometer (NIRS) returned 117,937 spectra, including over 80,000 of the asteroid Itokawa. This data set contains the calibrated spectra of Itokawa, including 111,226 spectra. For the NIRS raw spectra, see the PDS data set HAY-A-NIRS-2-NIRSRAW-V1.0. For 83,320 of the spectra, the data labels include the footprint coordinates indicating by asteroid latitude and longitude the specific area on the asteroid surface covered by each spectrum. The footprint information, illumination angles, and range for each of these spectra are also collected in a parameter table. NIRS is a grating infrared spectrometer with a 64-element indium-gallium-arsenide (InGaAs) linear detector array that covers the wavelength range of 750 - 2250 nm in increments of 24 nm. NIRS carries two types of onboard calibration targets, an incandescent halogen lamp and a light-emitting diode (LED). The basic unit of spectral data for the raw NIRS spectra is the digital number (DN), showing the integrated photon counts during a time-exposure interval. The raw data are originally sampled with 14 bits per channel (0 - 16383 DNs). A DN has a value of approximately 0.565 mV output from the detector preamplifiers when at a gain of 1.08. NIRS data are taken by stacking a number of sequential sets of light and dark frames at a single spectral measurement. Dark subtraction and data averaging are carried out with the on-board software, and only the dark-subtracted average, standard deviation, minimum, and maximum values for each channel are returned via telemetry. These are included in the FITS spectral tables as four separate columns within a single FITS file. The number of stacked frames is indicated by the STACK_COUNT keyword in the data labels, and also by the keyword STACK in the FITS header. STACK_COUNT, the number of stacked frames, is equal to two to the power of STACK. For further information about the NIRS instrument and its calibration, see Abe et al. (Unpublished). For a complete description of the processing of the calibrated spectra, see Kitazato et al. (2008). Data Organization and File Naming : Within the data/spectra directory, the data are organized into directories by mission phase (Approach, Gatepoint, Home Position, and Touchdown). In addition there are two calibration directories. Within these directories, the data files are in subdirectories by date. The filenames follow the convention nnnnnnnnnn_lvl3_0.fit, where nnnnnnnnnn is the spacecraft time of the image, and lvl3 indicates calibrated data with footprint information. The NIRS calibration procedure uses the ASCII table files (nirs_vol2rad_pls.tab for point light source and nirs_vol2rad_als.tab for area light source) to convert from raw NIRS output (Voltage) to radiance and the file nirs_solar_spc.tab to convert to I/F. These files are located in the data/calib directory. References : Abe, M., Y. Takagi, S. Abe, and K. Kitazato, Instrument calibration of the Hayabusa near-infrared spectrometer, Unpublished. (Included in the document directory of this data set.) Kitazato, K., B.E. Clark, M. Abe, S. Abe, Y. Takagi, T. Hiroi, O.S. Barnouin-Jha, P.A. Abell, S.M. Lederer, and F. Vilas, Near-infrared spectrophotometry of asteroid 25143 Itokawa from NIRS on the Hayabusa spacecraft, Icarus 194, 137-145, 2008.
DATA_SET_RELEASE_DATE 2010-06-07T00:00:00.000Z
START_TIME 2005-08-31T12:00:00.000Z
STOP_TIME 2005-11-24T12:00:00.000Z
MISSION_NAME HAYABUSA
MISSION_START_DATE 2003-05-09T12:00:00.000Z
MISSION_STOP_DATE 2010-06-13T12:00:00.000Z
TARGET_NAME 25143 ITOKAWA
ASTEROID
CALIBRATION
TARGET_TYPE ASTEROID
CALIBRATION
INSTRUMENT_HOST_ID HAY
INSTRUMENT_NAME NEAR-INFRARED SPECTROMETER
INSTRUMENT_ID NIRS
INSTRUMENT_TYPE SPECTROMETER
NODE_NAME Small Bodies
ARCHIVE_STATUS LOCALLY_ARCHIVED
CONFIDENCE_LEVEL_NOTE Confidence Level Overview : The highest quality spectra in this data set are those taken during the Gate Position phase of September 12-29, 2005, in which the accuracy of the NIRS footprint estimate is relatively high.
CITATION_DESCRIPTION Abe, M., Takagi, Y., Abe, S., and Kitazato, K., Hayabusa NIRS Calibrated Spectra V1.0. HAY-A-NIRS-3-NIRSCAL-V1.0. NASA Planetary Data System, 2011.
ABSTRACT_TEXT This data set includes the 111,226 calibrated spectra of asteroid 25143 Itokawa returned by the Near-Infrared Spectrometer (NIRS) instrument of the Hayabusa mission. The data cover the Itokawa encounter phases of the mission, from Aug. 31 through November 24, 2005.
PRODUCER_FULL_NAME CAROL NEESE
SEARCH/ACCESS DATA
  • SBN PSI WEBSITE
    		•