Current StatusOperation Status

The status of current satellite operation and Level1 product processing

1. Solar irradiance calibration data of the backside of diffuser acquired at around 21 UTC January 25, 2024 show poor quality.
2. It was confirmed that the rotation of the diffuser plate was not stable at the backside diffuser calibration position.
   After the backside diffuser calibration, the diffuser rotated safely and was stable at the frontside diffuser position. The solar irradiance calibration data of the frontside diffuser has been acquired normally.
   We are currently conducting a detailed investigation, including 164 events data of the past 15 years operation in space.

1. October 31, The bias correction set value of Zero Path Difference (ZPD) position had been accumulated and reached the limit.
   We suspended the FTS observation.
2. November 1, After the FTS reset operation, the FTS observation restarted.
3. Data missing period
   2022-10-31 03:01:09 to 2022-11-01 07:41:14(UT)

1. August 09 02:13:25 Path2 Zero Path Difference (ZPD)shift was accelerated.Since then, more than 1,000 half-laser fringes per day.The ZPD position counter reached its correction limit of 32,767 half-laser fringes on August 25.
2. August 25, Rest and Recovery: Increase the optical bench Temperature by 0.5 K and finer temperature control of the FTS-C by increasing the lower limit by 0.5 K to minimize the optical distortion andincreasetheelectricalphase-detectivity of the laser control system.This operation also increased the fringe data detection level (more robust).
3. August 26,Grid operation started with calibration data.August 31, Glint and target observation started.
4. Data missing period
   2021-08-24 20:05:28 to 2021-08-26 02:39:38

1. ・May 31: Zero Path Difference (ZPD) shift had started after 4-month stable period.
   ・June 13: after fast shift and frequent correction, bias-correction parameter reached its upper limit of 32,768. TANSO-FTS moved to the standby mode and was shutdown.
   ・Observation was suspended between 6/13 UT 04:33:09 - 6/17 UT 23:55:07.
   ・June 16: FTS was turned-on.
   ・June 17: 23:55 (UT) 3-point Cross-track observation without glint and target: twice and once TIR calibrations in day and night, respectively.
   ・June 21; ZPD shift has slowed down.
   ・June 22: Target observations of US West coast with the RRV calibration site and of Sahara. calibration site started: twice and 4 times TIR calibrations in day and night, respectively.
   ・July 6: target observations with previous patterns and glint started.
   
2. Data-missing periods
   Period when ZPD bias larger than 2,000 half-laser fringes.
   <1> from 2020-06-06 17:35:13 path29 scene43 to 2020-06-07 03:46:45 path03 scene56
   <2> from 2020-06-09 15:56:57 path26 scene42 to 2020-06-10 00:51:16 path44 scene09
   <3> from 2020-06-10 03:24:17 path03 scene43 to 2020-06-12 03:34:53 path05 scene09
   <4> from 2020-06-12 10:07:32 path17 scene09 to 2020-06-13 04:33:06 path06 scene25
   To be re-processed with the modified ZPD-bias correction parameter.

ZPD shift amount from May 31 to June 18.

Long term status of the TANSO-FTS operation and the L1B product.

1. On　24 Nov. 2018 (Sat),　GOSAT transferred to the least load mode (LLM) and TANSO-FTS and CAI were shut down due to the rotation anomaly of the second solar-paddle. As the Earth Sensor had been switched-off since Oct. 2018, the Sun Acquisition Mode (SAM) after the incident caused the orbit shift. GOSAT returned to the original orbit on 18 Dec. and TANSO-CAI observation and its data distribution were restarted on 21 Dec. 2018. TANSO-FTS restarted its observation and calibration on 28 Dec. and target observation on 31 Dec. 2018.
   After analyzing the TIR trend data since the restart, the parameters in the level 1 processing for TANSO-FTS TIR nonlinearity-correction will be updated and the level 1 data will be reprocessed as Version 220.
   
2. Data missing period;
   ・TANSO-FTS: 24/11/2018 17:26:46 (UT) - 28/12/2018 02:52:01 (UT)
   ・TANSO-CAI: 24/11/2018 16:50:37 (UT) - 21/12/2018 06:12:10 (UT)
   ・CAM-H8 (FTS field-of-view camera): 24/11/2018 16:51:21 (UT) - 28/12/2018 01:50:07 (UT)
   

Long term status of the TANSO-FTS operation and the L1B product.

1. On 17 May, 2018, GOSAT transferred to the least load mode (LLM) and all the instrument and data recorders were shut down due to the Command and Data Management System (CDMS) incident.The optics were cooled down and cryo cooler shut down.The condition was similar to the one when the rotation of the solar paddle stopped in May 2014.GOSAT restarted observing and communication with the ground stations and the data distribution was also restarted on 29 May 2018.
   After analyzing the trend since the restart, the parameters in the level 1 processing for TANSO-FTS TIR nonlinearity-correction will be updated and the level 1 data will be reprocessed as Version 220 (T.B.D.).
2. Data missing period;
   TANSO-FTS: 17/05/2018 18:48:25 (UT) - 24/05/2018 22:38:37(UT)
   TANSO-CAI: 17/05/2018 17:12:54 (UT) - 24/05/2018 21:50:20(UT)
   CAM-H8 (FTS field-of-view camera): 17/05/2018 18:48:29 (UT) - 24/05/2018 22:38:41(UT)

1. On Aug. 2, 2015, The band 4 detector-temperature increased from 70K to the environment temperature, while the short-wave infrared bands 1, 2 and 3 are operating normally and providing O₂, CO₂ and CH₄ spectra. TIR operations were stopped (switched off the TIR data processor and shut down cooler control electronics).
2. On Sep. 14, 2015, the cryocooler (pulse tube cooler) restarted the detector cooling. The most probable root cause of the sudden anomaly on Aug. 2, 2015 is a single event.
   The MCT detector temperature reached 70 K and JAXA resumed the ground data processing of all the TANSO-FTS bands (bands 1, 2, 3, and 4) from Sep. 15, 2015 (UT).

ZPD posiotion changing with time: After Cryocooler Restart.

Long term status of the TANSO-FTS operation and the L1B product. There is no change in TANSO-CAI operations.

1. • May 24, 2014, Rotation of one of the two solar paddles stopped. Still enough power to operate TANSO-FTS (TIR cooler, pointing mechanism), CAI.
   • Jun. 1, 2014, FTS observation restarted. Much Faster ZPD shift >> 800 fringe-biased interferogram. Needs new ILS (ILS800SS) for V161.160 or bias-correction apodization (V200.200). There is frequent spike flag 4 due to improper detection of the center burst.
2. • Since Sep. 4, 2014, Along track (AT) pointing settling down has become worse.
   • Sep. 11, 2014, 1 point (Nadir only) + glint + target mode instead of 3 point CT mode. About 30% interferogram has pointing instability.
   • Nov. 17-Dec. 5, 2014, PID control parameter tuning does NOT work (no improvement).
   • Since Dec. 3, 2014, AT stability became worse. Sep. 22-Oct. 5, 2014, AT angle was limited to within ±10 degrees.
   • From Dec. 15, 2014, Backup system test (wrong Level 1 geometry telemetry).
   • Jan. 26, 2015, optics path selector from the primary to the secondary.
   • Feb. 14, 2015, Level 1 data distribution (data with the back-up pointing mechanism).
   • Aug. 30, 2015, Pointing offset and misalignment were both reflected to Target observation requests planning.