SELENE Spacecraft CK files ================================================================================ The following SELENE C-kernel files containing the attitude of the SELENE Main Orbiter are available. "SEL_M_ALL_D_V01.BC" CK file of type 3 (continuous data) containing all available original attitude data derived from s/c telemetry and converted to SPICE CK format. The attitude is sampled at frequency of 2 seconds. The telemetry includes the attitude data as format of "IEEE Standard for Floating-Point Arithmetic" (IEEE 754) using 64 bits. "SEL_M_YYYYMM_D_V01.BC" A subset of data from "SEL_M_ALL_D_V01.BC". Each file archives monthly data. The contents are completely same as "SEL_M_ALL_D_V01.BC". "SEL_M_ALL_S_V01.BC" CK file of type 3 containing all available original attitude data derived from s/c telemetry and converted to SPICE CK format. The differences between "SEL_M_ALL_D_V01.BC" and "SEL_M_ALL_S_V01.BC" are frequency, precision, and time coverage following its telemetry-mode. In this file, the attitude is sampled at frequency of 8 seconds. The precision in the s/c telemetry uses a single-precision (32 bits). The number of time gaps is less than that of "SEL_M_ALL_D_V01.BC". "SEL_M_YYYYMM_S_V01.BC" A subset of data from "SEL_M_ALL_S_V01.BC". Each file archives monthly data. The contents are completely same as "SEL_M_ALL_S_V01.BC". Version and Date -------------------------------------------------------------------------------- Version 1.0 -- June 1, 2010 -- Yukio Yamamoto, ISAS/JAXA The first reconstructed release. L2DB version sometimes includes invalid values depending on the processing error in engineering value conversion. In this version, these errors are removed, and files archived in every month are prepared for convenience. L2DB version -- November 1, 2009 -- SELENE project The initial release by SELENE project at the following URL: https://www.soac.selene.isas.jaxa.jp/archive/ The "original" directory contains the same data set of this version. Data Gap -------------------------------------------------------------------------------- In the following time periods, the attitude data is not available. The reasons of these gaps are briefly described. During these periods, most of the scientific instruments on SELENE turned off, therefore the affection by these gaps is minimized for scientific analysis. The time in the following table is represented in Barycentric Dynamical Time (TDB), SPICE internal default. The gaps in October 2007 are not listed in the following table because there are too many gaps due to initial function checks. The file "SEL_M_ALL_S_V01.BC" often covers the attitude data even in these period. Gap Start Gap End Reason ----------------------------------------------------------------------------- 2007-11-10T12:01:35.255 2007-11-10T12:07:11.255 Unloading Function Check 2007-12-11T03:00:39.841 2007-12-11T06:03:47.845 Altitude Keeping Maneuver 2007-12-18T06:08:00.028 2007-12-19T07:48:08.068 Low Load Mode 2007-12-30T00:56:16.450 2007-12-30T23:04:40.489 MDR operation failure 2008-02-04T23:41:23.727 2008-02-06T23:41:47.769 Lunar eclipse operation 2008-03-29T19:26:04.391 2008-03-29T22:11:48.393 Altitude Keeping Maneuver 2008-04-02T20:59:34.461 2008-04-02T22:33:48.462 Yaw around operation 2008-05-24T15:41:11.094 2008-05-24T17:49:43.095 Altitude Keeping Maneuver 2008-07-16T11:31:11.048 2008-07-16T13:39:49.052 Altitude Keeping Maneuver 2008-07-28T01:04:33.522 2008-07-28T23:40:05.558 Reaction Wheel 1 trouble 2008-08-03T02:36:03.715 2008-08-03T04:38:49.718 Orbit plane change maneuver 2008-09-02T00:43:56.332 2008-09-02T03:03:48.334 Orbit plane change maneuver 2008-09-10T09:28:56.472 2008-09-10T12:03:48.474 Altitude Keeping Maneuver 2008-10-01T01:16:02.852 2008-10-01T03:49:48.855 Altitude Keeping Maneuver 2008-10-07T06:23:04.986 2008-10-07T07:52:48.988 Yaw around operation 2008-11-03T03:44:27.489 2008-11-03T06:18:49.490 Altitude Keeping Maneuver 2008-12-27T00:42:52.923 2008-12-27T02:50:48.928 Reaction Wheel 3 trouble 2009-02-09T12:21:04.948 2009-02-09T15:50:48.951 Lunar eclipse operation 2009-02-20T21:44:05.161 2009-02-21T00:07:49.163 Altitude Keeping Maneuver 2009-03-19T18:31:05.470 2009-03-19T21:20:49.471 Altitude Keeping Maneuver 2009-04-03T07:44:01.653 2009-04-03T09:12:49.654 Yaw around operation 2009-04-16T17:56:03.854 2009-04-16T20:44:49.856 Altitude Keeping Maneuver 2009-06-10T16:57:38.631 2009-06-10T18:00:24.632 Impact operation ----------------------------------------------------------------------------- Special Event for attitude -------------------------------------------------------------------------------- There are several special events for attitude. The SELENE spacecraft normally maintained its +Z axis toward the center of the moon direction, but the special attitude control was performed followed by the requirements of scientific instruments. The following time table shows the events and its timing. Start Time Stop Time Event ---------------------------------------------------------------- 2007-11-19T06:00:00 2007-11-19T13:30:00 LISM(SP) Calibration 2008-03-21T18:00:00 2008-03-21T20:30:00 LISM(SP) Calibration 2008-07-03T21:30:00 2008-07-04T11:00:00 CPS Calibration 2008-09-15T06:30:00 2008-09-15T14:30:00 LISM(SP) Calibration 2008-12-11T04:00:00 2008-12-12T23:00:00 GRS Calibration 2008-12-27T21:00:00 2008-12-28T07:30:00 LISM(MI) Calibration 2009-03-12T01:30:00 2008-03-12T03:00:00 LISM(SP) Calibration ---------------------------------------------------------------- LISM(SP) Calibration (roll-cant maneuver) ------------------------------------------ LISM (SP) calibration was carried out to observe a calibration site on the moon (Apollo 16 landing site). This maneuver is called as "roll-cant" because the SELENE body rotates around x-axis (roll axis) when SELENE flied over around the calibration site. CPS/GRS/LISM(MI) calibration ------------------------------------------ To observe the space background or stars, the orientation of the SELENE orbiter was fixed with respect to the inertial space. Its +z axis is directed toward space during half around the moon. Contact -------------------------------------------------------------------------------- Yukio Yamamoto Japan Aerospace Exploration Agency Institute of Space and Astronautical Science 3-1-1 Yoshinodai, Chuo, Sagamihara, Kanagawa, 252-5210 JAPAN