SELENE Spacecraft CK files ================================================================================ The following SELENE C-kernel files containing the attitude of the SELENE Main Orbiter are available. "SEL_M_ALL_D_V02.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_V02.BC" A subset of data from "SEL_M_ALL_D_V02.BC". Each file archives monthly data. The contents are completely same as "SEL_M_ALL_D_V02.BC". "SEL_M_ALL_S_V02.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_V02.BC" and "SEL_M_ALL_S_V02.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_V02.BC". "SEL_M_YYYYMM_S_V02.BC" A subset of data from "SEL_M_ALL_S_V02.BC". Each file archives monthly data. The contents are completely same as "SEL_M_ALL_S_V02.BC". Version and Date -------------------------------------------------------------------------------- Version 2.0 -- July 1, 2011 -- Yukio Yamamoto, ISAS/JAXA The attitude data before and after the gaps are corrected. 1) Recover the first point just after each gaps in "SEL_M_ALL_D_V01.BC" 2) Remove invalid data of non-existence points in "SEL_M_ALL_S_V01.BC" where the non-existence points mean the s/c packets to make attitude data are incomplete, and the attitude data is lacked at the time. The previous version "SEL_M_ALL_S_V01.BC" includes invalid values at these non-existence points just before some gaps, and CK readers return invalid attitude as a result. Removing the attitude data of these non-existence points, some data is not available which is available in "SEL_M_ALL_S_V01.BC". In addition, some attitude data interpolated with invalid values are corrected. The summary of the differences is in the followings: 2007-10-08T22:51:51.552 - 2007-10-08T22:51:59.552 no data 2007-10-13T00:15:35.553 - 2007-10-13T00:16:07.553 corrected 2007-10-13T00:16:39.552 - 2007-10-13T00:22:07.552 no data 2007-11-10T12:00:24.072 - 2007-11-10T12:00:32.072 no data 2007-12-19T07:05:52.883 - 2007-12-19T07:06:00.883 no data 2008-02-06T03:42:18.570 - 2008-02-06T03:42:42.570 corrected 2008-02-06T04:19:38.570 - 2008-02-06T04:19:46.570 no data 2008-02-06T09:35:46.574 - 2008-02-06T09:35:54.574 no data 2008-02-06T11:21:06.576 - 2008-02-06T11:21:46.576 corrected 2008-02-06T11:28:10.576 - 2008-02-06T11:30:02.576 corrected 2008-02-06T11:31:54.575 - 2008-02-06T11:32:02.575 no data 2008-02-06T13:25:46.577 - 2008-02-06T13:26:34.577 corrected 2008-03-29T19:24:51.205 - 2008-03-29T19:24:59.205 no data 2008-06-01T09:07:16.053 - 2008-06-01T09:07:40.053 corrected 2008-07-28T01:03:18.338 - 2008-07-28T01:03:26.338 no data 2008-11-03T03:43:12.306 - 2008-11-03T03:43:20.306 no data 2009-02-09T12:19:46.763 - 2009-02-09T12:19:54.763 no data 2009-02-09T15:22:58.766 - 2009-02-09T15:23:06.766 no data 2009-03-19T18:29:47.285 - 2009-03-19T18:29:55.285 no data 2009-03-19T20:18:27.285 - 2009-03-19T20:18:35.285 no data Version 1.2 -- April 1, 2011 -- Yukio Yamamoto, ISAS/JAXA Some of the attitude data on February 4 to 6, 2008 are recovered although there is intermittent discontinuity. In addition, the wrong description of this document on the Data Gap table is fixed in the following: v1.1 (wrong) : Lunar eclipse operation v1.2 (correct): Altitude Keeping Maneuver Version 1.1 -- November 1, 2010 -- Yukio Yamamoto, ISAS/JAXA Most of the attitude data obtained on December 30, 2007 are recovered. The data gap is decreased in the followings: v1.0 : 2007-12-30T00:55:11.266 2007-12-30T23:03:35.305 UTC v1.1 : 2007-12-30T00:55:11.266 2007-12-30T09:00:05.280 UTC 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 Coordinated Universal Time (UTC). 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_V02.BC" often covers the attitude data even in these periods. Gap Start Gap End Reason ----------------------------------------------------------------------------- 2007-11-10T12:00:30.072 2007-11-10T12:06:04.072 Unloading Function Check 2007-12-11T02:59:34.658 2007-12-11T06:02:40.662 Altitude Keeping Maneuver 2007-12-18T06:06:54.844 2007-12-18T13:59:54.857 Low Load Mode 2007-12-19T07:05:58.883 2007-12-19T07:47:00.884 Unknown 2007-12-30T00:55:11.266 2007-12-30T09:00:03.280 MDR* operation failure 2008-02-04T23:40:18.542 2008-02-06T23:40:40.584 Altitude Keeping Maneuver 2008-03-29T19:24:59.205 2008-03-29T22:10:41.207 Altitude Keeping Maneuver 2008-04-02T20:58:29.275 2008-04-02T22:32:41.276 Yaw around operation 2008-05-24T15:40:05.909 2008-05-24T17:48:35.910 Altitude Keeping Maneuver 2008-07-16T11:30:05.865 2008-07-16T13:38:41.869 Altitude Keeping Maneuver 2008-07-28T01:03:28.338 2008-07-28T23:38:58.375 Reaction Wheel 1 trouble 2008-08-03T02:34:58.532 2008-08-03T04:37:42.535 Orbit plane change maneuver 2008-09-02T00:42:51.150 2008-09-02T03:02:41.151 Orbit plane change maneuver 2008-09-10T09:27:51.289 2008-09-10T12:02:41.291 Altitude Keeping Maneuver 2008-10-01T01:14:57.670 2008-10-01T03:48:41.672 Altitude Keeping Maneuver 2008-10-07T06:21:59.804 2008-10-07T07:51:41.806 Yaw around operation 2008-11-03T03:43:22.306 2008-11-03T06:17:42.308 Altitude Keeping Maneuver 2008-12-27T00:41:47.739 2008-12-27T02:49:41.744 Reaction Wheel 3 trouble 2009-02-09T12:19:58.763 2009-02-09T15:49:40.766 Lunar eclipse operation 2009-02-20T21:42:58.976 2009-02-21T00:06:40.977 Altitude Keeping Maneuver 2009-03-19T18:29:59.285 2009-03-19T21:19:41.286 Altitude Keeping Maneuver 2009-04-03T07:42:55.467 2009-04-03T09:11:41.468 Yaw around operation 2009-04-16T17:54:57.669 2009-04-16T20:43:41.670 Altitude Keeping Maneuver 2009-06-10T16:56:32.446 2009-06-10T17:59:16.447 Impact operation ----------------------------------------------------------------------------- * MDR ... Mission Data Recorder 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 was called as "roll-cant" because the SELENE body rotated around x-axis (roll axis) when the SELENE spacecraft flied over around the calibration site. CPS/GRS/LISM(MI) Calibration ------------------------------------------ To observe the space background or stars, the orientation of the SELENE spacecraft 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 email: darts-admin@ML.isas.jaxa.jp