INTEGRAL Commissioning & PV phase results
INTEGRAL Commissioning & PV phase results
The observations of revolution 25 were executed as planned. The revolution started with the continuation of the empty field observation, followed by the OMC flatfield observation and the Test GPS. The execution of the test GPS was closely followed by the instrument teams and at ISDC. At the begin of the revolution the bad PICSIT pixel already observed and removed in revolution 24 re-appeared. The bad pixel was killed again and this time also saved in the IBIS context preventing its re-occurence in future.
Observations of revolution 24 were executed according to plan pointing for the entire revoution to the Empty Field 2. From December 24 at 0900Z PICSIT was operated in PPM mode for 90ksec at high TM rate, while SPI was operated at the minimum TM rate. After some monitoring a PICSIT bad pixel was killed in the afternoon of December 24. In the morning of December 25 ISDC did not receive TM from MOC. The remainder of the revolution the satellite stayed at the same pointing and operation went smooth. A burst was detected in the SPI ACS data on December 26 at 14:35.
Revolution 23 was executed as planned. Rather smooth revolution. GRB021223 (reported in the GCN GRB observation report #1778) was seen by SPI ACS. The solar flare on Dec 21 at 11h10 UTC was seen by ACS and JEM-X.
The observations of this revolution were executed as planned. The solar activity was high during this revolution and kept the ISDC shift team busy to distinguish between solar flares and GRBs. A burst in the partially coded FOV was detected and localized on December 19 at 7:33 UTC and reported in a GCN (#1766). The initial position was refined within 6 hours (GCN #1768) and the position uncertainty reduced donwn to 4 arcminutes. The timelines (input for automated commanding) of the remaining PV activities up to December 30 were generated by ISOC and MOC. The instrument teams prepared the required input for the execution of the dedicated IBIS background field observation on December 24. During this observation PICSIT is operated in photon-photon mode for a period of 90ksec with a very high telemetry allocation (85% of the total available telemetry). The accumulated data will be used to calculate improved PICSIT background maps.
The revolution was excuted with the observations as planned. The first revolution with a new dither dwell time of 2200 sec.
SPI had a high TM allocation for a duration of 90ksec in total, which allowed to downlink all data in photon-photon mode (in normal operation single events are downlinked as onboard accumulated spectra).
On December 16 at 07:38Z IREM suffered a Single Event Upset and indicated a failed condition. IBIS, JEM-X and OMC reacted correctly and went into their Safe Mode. SPI continued data accumulation at the high TM rate, as the IREM input to SPI was not enabled. IREM was brought back into its normal operation mode and after some time of monitoring the onboard IREM broadcasting was enabled again.First light data were presented at ESA HQ to the press (18 Dec).
A swift replanning of revolution 25 was required to consider the unavailability of the Goldstone station due to a launch support (from December 13 18:27 to December 14 at 02:15). The replanning led to the exposure durations as indicated in the planned section. On Saturday December 14 at 16:21Z an AOCS command failed verification on the ground before uplink. As a consequence the automatic timeline for the AOCS system was disabled until the problem (on the ground) was understood. The timeline was rejoint at 21:31Z. No slews were performed in between and 11 dither pointings were missed.
Revolution 19 was executed as planned. The timeline had to be interrupted in two occasions. Once when during a ground station handover the ground station only become available after a short delay and once when the guide star was not found in the inital mapping of the star tracker. Five dithering points were lost because of this. On December 10 the OMC remote commanding through IBAS was tested. After having fixed an initial inconsistency between the systems the remote commanding was validated and the proper functioning was confirmed.
Revolution 18 was executed as planned. For the first time the entire revolution was executed based on ISOC planning input. Revolution 18 was the last PV revolution consisting entirely of staring observations. From now on until December 24 dithering observations will be executed. The revolutions up to 24 contain observations mainly for SPI calibration
purposes.Some manual commanding at begin of revolution 18 were required to change instrument parameter settings based on instrument team input. At the ground station handover a recovery of the timeline was required after a delay in the ground station readiness.
JEM-X commissioning activities were performed as planned.. The JEM-X was pointed 2, 3, 4, 5 and 6 degree off from Cygnus X-1 to calibrate the detector off-axis response and to investigate a possible cross talk between the two JEM-X cameras. In addition, JEM-X was configured in various primary and secondary telemetry formats to validate these configurations. In the remainder of the revolution the IBIS Cygnus X-1 on-axis staring calibration observation was continued.
During the night from 2002/12/1 to 2002/12/2, 4 hours of data were lost during the Goldstone passage. On 2002/12/03 a payload comissioning status meeting took place at ESOC with participation from all instrument teams. The status of instrument commissioning was reviewed in preparation for the Mission Commissioning Readiness Review scheduled for Dec 12 & 13.
PV observations executed as planned, staring on Cygnus X-1. First revolution with reduced JEM-X TM allocation. In the middle of the revolution the JEM-X configurations were swapped between JEM-X1 and JEM-X2. Some ISGRI modules continue to show high count rates.
Executed as planned, a long Cygnus staring observation. JEM-X is doing tests with the discriminator setting to lower the energy threshold. JEM-X configuration for remainder of PV revolutions was redefined in view of the recently agreed TM allocation for JEM-X.SPI did tests on the spectra accumulation duration. Spectra were accumulated with a duration of 1h and 2h. The maximum possible duration was calculated as 9h.
Observations executed as planned with a 100ksec pointing on the empty field 1 and a subsequent staring observation on Cygnus X-1 for the rest of the revolution.PICSIT was operated in photon-photon mode during the Cygnus observation. In this period a GRB burst was detected. A GCN was issued. ISGRI registered the burst as well. At the time of the burst SPI was not operated in photon mode and was only acquiring spectra, GRB seen in SPI-ACS.
OMC full FOV image succesfully acquired. The ISWT took place and it was decided that INTEGRAL will begin the operational phase operating with only one JEM-x unit at a time.
Empty field 1 09:59:21.79,-00:58:55.21 full revolution, staring SPI PV activities:
SPI continues to lose packets per cycle. PSD library had to be uploaded twice because initially the least and most significant bits were swapped.Due to Goldstone outage and re-loading of PSD library only 8h of data are available for the PSD table verification (instead of 24h). Only a limited validation of the PSD library is possible.
The 10 ksec science observation on the empty field was not executed, as an AOCS calibration was performed instead.
OMC was left in science mode during the AOCS calibration which led to a generation of 8h not meaningful data.
Payload
SPI is in nominal science mode and operations are being conducted in accordance with the automatic timeline.
IBIS Instrument tuning completed on the 20th. Calibration activities will start during revolution 13 and will continue into December.
JEM-X is in data taking mode and operations are being conducted in accordance with the automatic timeline. For safety reasons the instruments are currently put in Safe Mode 90 minutes before the altitude of 60.000 Km is reached.
The OMC is operating nominally and operations are being conducted in accordance with the automatic timeline.
IREM is nominal. No special activities were conducted.
The routine operations, such as slews or the activities related to the Perigee Passage have been performed from the automatic Timeline while most of the calibration activities were performed using manual commands.
A slew operation to the avoidance attitude for the Leonids crossing was conducted at 15:55 UTC on the 18th. The Instruments / platform were manually commanded to a safe configuration for this event. The Leonids passage continued until 17:30 on the 19th. At 19:30 on the 19th the Instruments and platform were manually commanded to resume the nominal configuration.
Service Module:
The service module is nominal. Wheel biasing operations
were conducted on the 18th at 08:27UTC, 15:30 UTC and 18:42 UTC
Payload:
On the 20th at 00:25 UTC Science
operations were selected by the Pointing Observation
Schedule for OMC, JEMX and IBIS.
SPI was in the nominal science mode during this reporting period. A slew back to the Empty Field 1, fulfilling the SPI-314 commissioning test constraints was conducted at 23:07 UTC on the 19th. Tuning of the SPI PSAC for the sensitivity of the detector was started on the 20th at 00:40 UTC. Two 12-hour acquisitions in Operational Mode will be conducted. One with the Plastic Veto (PSAC) off and one with the PSAC on.
IBIS Instrument tuning is still on going.
JEM-X is in data taking mode and operations are being conducted in accordance with the automatic timeline. After the identification of the problems with the anodes the JEM-X 1 has been operated at lower voltages (80 V below nominal). This reduced the gain by a factor of 2.6. Apart from this the instrument is performing well. For safety reasons the instruments are currently put in Safe Mode 90 minutes before the altitude of 60.000 Km is reached.
The OMC is operating nominally. One OMC image acquisition has been performed each day with a minimum duration of 45 minutes. Outside these periods OMC was in Stand-by mode.
IREM: The unit is nominal. No special activities were conducted.
General:
The routine operations, such as slews or the activities related to the Perigee Passage have been performed - for the first time - from the automatic timeline using scheduling input from ISOC, while most of the calibration activities were performed using manual commands.
Automatic timeline will be the baseline for the routine missions operations.Spacecraft:
The service module is nominal. Wheel biasing operations were conducted on the 16th at 19:26 UTC. RMU calibrations were conducted on the 16th at 08:51 and on the 17th at 03:51 and 20:29 UTC.Payload:
First astronomical target (Cyg X-1) was observed and IBIS/ISGRI and SPI produce first images.SPI was in the nominal science mode during this reporting period. Tests were conducted for SPI influence of ACS thresholds on the background.
IBIS Instrument tuning is still on going.
JEM-X is in data taking mode and operations are being conducted in accordance with the automatic timeline. After the identification of the problems with the anodes the JEM-X 1 has been operated at lower voltages (80 V below nominal). This reduced the gain by a factor of 2.6. Apart from this the instrument is performing well. For safety reasons the instruments are currently put in Safe Mode 90 minutes before the altitude of 60.000 Km is reached.
The OMC is operating nominally. One OMC image acquisition has been performed each day with a minimum duration of 45 minutes. Outside these periods OMC was in Stand-by mode. On OMC the PV phase Dark Current and Flat Filed Calibration activities
that started at 12:50:00 UTc on the 15th of November continued until 10:00 UTC on the 16th.A slew from the OMC calibration target to CYGNUS-X1 was conducted on the 16th between 19:51Z to 20:18Z.
The IREM unit is nominal. No special activities were conducted.
The service module is nominal. Wheel biasing operations were conducted on the 15th at 08:37 UTC.
Payload
SPI was in the nominal science mode during this reporting period. Test
were conducted for SPI influence of ACS thresholds on the background.
IBIS:
Instrument tuning is still on going. Additional activities requested
by IBIS PI in order to improve the fine-tuning of the HV setting
for the CDM 01 were conducted. The optimisation for the Compton angle is
completed
The Low Threshold Adjustment calibration has been executed in automatic
mode, using the data files provided by ISDC, as planned on the 15th of
November (REV # 11). The interfacebetween MOC-ISDC was successfully tested
for the generation of the new ISGRI context tables (CTX) used during the
LTA. From the scientific side, formation of tracks (with a frequency
of 1 event every 5 minutes) have been observed in the PICsIT detector plane,
originating from the interaction of cosmic rays with the atoms of the scintillators.
Scientific analysis is on going. This is considered as a clear indication
of the good health status of IBIS detectors & electronics and demonstrating
the imaging capability of the instruments.
JEM-X
JEMX was in data taking mode until 60000 km descend time - 90 minutes
on the 14th. After 40000 km ascending in revolution #11, 15th of
November, both JEMX units' high voltages, HV, were switched on to
the agreed lower HV settings and then JEMX units were set to data taking
mode.
OMC:
Execution of the OMC Dark Current & Flat Field calibrations
started on the 15th and will continue until 16th.
IREM:
The unit is nominal. No special activities were conducted.
The service module is nominal. No special activities were conducted.
Payload
SPI was in the nominal science mode during this reporting period. The
following SPI operations were conducted:
IBIS is working in normal science mode. The following activities
were conducted:
JEMX-1 and 2 was in data taking mode until 00:30 UTC on the 14th
of November. From this time, at Empty field1 attitude, Diagnostic Data
Collection (36 acquisitions) on both JEMX 1 and 2 was conducted. Following
this both units will be configured to Data Taking mode until 90 minutes
before 60000 km descending altitude when they are switched to SAFE mode
by time tag telecommands.
OMC in standby mode. Only one image acquisition on the 14th at 09:28 UTC to 10:30 UTC was conducted, at Empty Field 1 attitude, upon request from the PI.
Due to the size of the IREM housekeeping, HK, buffer it was necessary
to set the down loading of the HK to every 240 seconds, in order to recover
IREM HK data during the ground station outage period.
Payload
SPI:
SPI was in the nominal science mode during this reporting period. The
following SPI operations were conducted:
IBIS:
IBIS is working in normal science mode. The following activities were
conducted:
JEM-X:
Both JEM-Xs were configured to safe mode. The following operations
were conducted:
OMC:
The OMC is in standby mode.
IREM:
Nominal.
Spacecraft:On the 9th of November a worst case slew manoeuvre was conducted. The purpose of this test was to command a very long slew, approximately 163 degrees, with the wheels close to their stability constraints while observing the resulting slew errors. The test required approximately 7 hours to complete and included a slew back to the science attitude. The slew ended with an error of about 5020 arcsec, which means an error of 0.87 % with respect to the slew length. This is better than the specification. However, the slew back to the science pointing, which was shorter and at a bit higher altitude caused a bigger error. Hence, it is possible that shorter slews might have relatively larger errors. This is due to the fact that the larger slews have more stringent conditions.
SPI:
SPI was in the nominal science mode during this reporting period. Performance tests and fine-tuning of subassemblies were conducted. No anomalies were detected.IBIS:
IBIS was working in normal science mode during this reporting period. Throughout the weekend parameter optimization of the instrument was performed. No anomalies were detected. On the 12th of November it is planned to perform a calibration of the ISGRI.JEM-X:
Both JEM-X units were configured to safe mode on November 7th. Tests were successfully conducted with JEM-X1 on the 11th with a lower High Voltage value. The origin for the observed degradation of some anode strips of the microstrip detectors in both units is under investigation.OMC:
The OMC was in stand-by mode during this reporting period.IREM:
IREM is functioning well but it was observed during this weekend that it was down-loading data 8 hours in the past. On the 12th of November it is planned to toggle the operational mode from "INTEGRAL" to "Standard" and back again in order to
correct this problem.
Service Module:
Star Tracker bright object test were performed between 09:00 UTC to
16:00 UTC. The Star Tracker behaviour was nominal and the tests were successful.
SPI:
The instrument operates in Photon Mode.The detector temperature has
a positive trend toward 90K, due to the new cryocooler stroke settings
uplinked yesterday. Further stroke tuning expected within two days to stabilise
around this temperature.
IBIS:
Full IBIS nominal activation terminated yesterday. The IBIS parameter
optimisation phase is planned to start this evening and
continue for the next days. IBIS is now working in Standard mode, with
VETO HV switched on, PICSIT and ISGRI in nominal.
JEM-X, unit #2:
During the data analysis by JEM-X PI of a test with low discriminator
settings scheduled last night until this morning, the distribution of event
counts showed an irregularity. On request of the PI both JEM-X instruments
have been turned to safe mode by the Flight Control Team until further
instructions. Cause of anomaly is under investigation.
OMC:
The daily imaging ops have been performed while at Canopus attitude
for the star tracker bright object test.
The energy resolution of the SPI Ge detectors at 4000V are nominal except detector 15 which is slightly worse. The HV of detector 15 will be adapted in order to find the best compromise.
IBIS: The Anticoincidence System (VETO) has been completely switched on at the beginning of rev.7, after the 14 days outgassing period. The ISGRI detector shows the expected behaviour with the vetoed events. Full nominal activation is scheduled and currently on-going. software dump of the VETO electronic box could be performed successfully.
JEM-X:
The JEM-X 1 and 2 were successfully re-activated at radiation belt
exit and are working in Data Taking mode. No special activities were performed.
OMC:
The OMC is in stand-by mode. Regular imaging operations are conducted.
IREM:
The IREM is working nominally. Initial measurements indicating the
start of the electron belts at 60000 km have been confirmed by the count
rates of the other instruments. As a consequence the radiation belt entry
limit (stop of any instrument activity and transition to the safe configuration)
is now considered at 60000 km, since revolution 7.
SPI proceeded to the first switch on of the High voltages and found all the Ge Detectors alive with nominal performances except detector 15 which shows a 'typical" degradation by pollution .
All the SPI electronics were found in good health :
SPI DFEE processes nominally the incoming data flow from detectors, veto and pulse shape discrimination and groups correctlly the events.
SPI pulse shape discrimination (PSD) provides curves and processes the data as expected.
SPI veto system provides anticoincidence signal that reject a high fraction of the background (reduction by a factor up to 25 without any tuning)
JEM-X successfully detected Cen X-3.
Launch and Early Operations Phase (LEOP) succefully terminated.
SPI active cooling started. Cryo-coolers switched on and cooling rate is nominal.
Four ISGRI modules switched on with nominal bias voltage. PICIST is nominally on. Veto system is off until completion of outgassing.
JEM-X nominal. Slew to first target Cen X-3.
OMC nominal.
IREM nominal: initial measurements indicate start of electron belts (inbound orbit) starts at 60.000 km.
Final perigee burn completed raising the perigee height to the nominal value of 9000 km - well above the proton belts.
SPI passive cooling started.
Calibration of SPI Anti-coincidence is proceeding nominally.
A small apogee altitude adjustement manoeuver was successfully performed to ensure that the period of the Integral orbit is exactly 72 hrs.
All SPI subsystems in nominal mode (except cryo coolers which are off). Anticoincidence high voltage set to nominal value. Performance as expected.
All IBIS electronic boxes are on. ISGRI modules in nominal mode with bias set to zero. PICSIT modules are peridodically switched on for check. Veto subsystem off until end of outgassing. Dump of memories for electronic boxes for PICSIT and Veto so far unsuccsesful.
JEM-X working in nominal mode.
OMC working in nominal mode.
IREM in nominal mode.
JEM-X entered safe mode during radiation belt approach, because of high count rate as triggered by IREM, at apx 52.000 km altitude, i.e. about 1.5 hours before the nominal altitude of 40.000 km.
Some problems have still been experienced with the provision of telemetry
and telecommand services from NASA's DSN station Goldstone during consecutive
passes over DSS-16. Investigations are on-going to stabilise the situation.
The 2nd and 3rd perigee raise burn maneouvres were successful (2002/10/26); their combined effects raised the perigee height from 2269 km to 7231 km, using 208.4 kg of fuel. Apogee height is 152890 km. AOCS and reaction wheel system were perfect during maneouvres.
The SPI ACS activation proceeded as planned, and all is well. Congratulations to the SPI team!
The Jem-X HV nominal activation has started today, as planned, and is proceeding normally.
The ground segment reports a number of problems, all of which are understood
and the problems are either fixed, or workaround solutions are being implemented:
+ Unavaibility of Goldstone ground station for few hours (2002/10/24)
+ Some data packets were not received at PI workstations
+ Timing accuracy of data provided by Goldstone does not meet specification
Payload status:
SPI: Continues in outgassing mode. Data processing electronincs (DPE) and all units switched on. Detector temperature is controlled at +38 deg C. Cryocooler electronics in stand-by. Memory dumps of digital front end electronics, anti-coincidence subsystem, pulse shape discrimination subsystem and DPE software were performed and showed no problems.
IBIS: First ISGRI module (#4) switched on (first light data), commanded in science mode. Preliminary analysis of data from one PICSIT semi-module and one ISGRI module are under investigation. The background activation due to perigee passages is clearly visible (as expected), assessment of the background is on-going, awaiting however full activation of IBIS including the veto subsystem in final orbit.
JEM-X: Completion of electronic calibration. Initial setting of High Voltage at low values on-going.
OMC: working very well in nominal mode.
IREM: nominal
OMC continued checking its on-board star centroiding algorithms using
a set of new images.
One of the 8 ISGRI modules was successfully activated and operated for
approximately 2 hours.
SPI: in outgassing mode. Cryocooler control electronics in stand-by.
IBIS: electronic units switched on. PICSIT switched on and in photon-by-photon
mode. First sky images collected. Nominal performance.
JEM-X: Electronic cal on-going and nominal. Gas pressure nominal.
OMC: CCD baking complete. DPE on and nominal. First flat field exposure
(cover closed).
IREM: in nominal operating mode. Preliminary selection of best two
scalers for nominal mission.
The orbit determination confirms perfect performance of the PROTON launcher and its upper stage.
SPI: DPE and all sub-assemblies are activated, outgassing started at
+37 deg C
IBIS: No instrument related activities.
JEM-X: DPE's activated and on-board s/w dump
OMC: CCD baking operations started.
IREM: has been fully activated