ROSINA COPS operation during Lander Test Report for the period 24. Feb. 2010 Table of Content 1. COPS 2. Conclusions 1. COPS The nude gauge of COPS was switched on to the highest sensitivity. No sensor problems were encountered with COPS during the whole period. The pressure measured by COPS for the whole period can be seen in fig. 1. Fig. 2: details of the lander test The data shown have a time resolution of 1 min. Data with 2 s resolution are available upon request. 2. Conclusions The outgassing from the -x panel (lander?) is considerable and a point of concern for ROSINA. During the comet mission illumination of this panel has to be either omitted or otherwise the panel has to be baked out by the Sun for a long time. ROSINA RTOF activities Report for the period 16. Feb.-4. March 2010 Table of Content 1. Purpose of test 2. Test plan 3. Results 3.1. Day 1 3.2. Day 2 3.3. Day 3 3.4. Day 4 3.5. Day 5 4. Next steps 5. Anomaly reports /Cruise Phase Payload Checkout Requirements 6. Conclusions 1. Purpose of test Since September 2004 RTOF showed partial discharges whenever the 9 kV converter was switched on. This led to a generally unstable behavior of the instrument which resulted in many different error reports, shut-off of the sensor by the DPU and finally, in March 2005 to an increase of the 24V current to >60 mA (from <30 mA) and a decrease of the highest voltage achievable to <3kV. After the same problems also occurred in the lab the reason for this behavior was located in the potting of the high voltage board. Subsequently, the instrument in space was only switched on for short times to see if the behavior changed due to outgassing. However, the current on the 24V always remained high during these tests. The solution, just to let RTOF outgas long enough seems not to work. Our electronics engineer then came up with the idea to chop the 24V input of the 9 kV converter, that is to switch it on / off in regular intervals, a solution which can be implemented in the DPU and which doesn't need a hardware fix. This solution was tested first on the stand-alone HV board in vacuum, later on the RTOF FM in the lab, both for several months. No discharges occurred; the voltage could be regulated by changing the off-time to within +/- 100V. The voltages used for the ion optics are all derived from this converter. As long as they are below the regulated voltage they are stable. The ion optics of RTOF can be tuned to lower voltages without loosing too much of the performance. At lower voltages the mass resolution should remain the same, but the mass range and/or the sensitivity will be somewhat lower. It was clear, however, that the RTOF FS in space is different from the one in the lab because of this incident in March 2005 with the enhanced 24V current. That points to a carbon trace which is a parallel resistance to the ion optics . 2. Test plan Day 1, 16. 2.: Switch on 9 kV by using the orthogonal source lense as regulation voltage. Find the optimal parameters for Ton (on-time of the 24V current at the 9 kV converter), the step width (ms/V), the minimum and maximum Toff. Monitor the voltage and the 24V current for several hours. Day 2, 23. 2.: Implement the parameters found on day 1 and switch on all voltages belonging to the storage source. Switch-on the detector, the filament , the data acquisition board, ETS, and read out data. Day 3, 25. 2.: Switch on all voltages belonging to the orthogonal source by using the storage source lense as regulation voltage. Switch-on the detector, the filament, the data acquisition board, ETSL, and read out data. Day 4, 1. 3.: Optimize the storage source voltages in order to get mass spectra. Day 5, 4. 3.: Optimize the ortho source voltages in order to get mass spectra Day 6, TBD.: Get mass spectra from RTOF by using modes out of pass and, if possible, parallel to DFMS 3. Results 3.1. Day 1 The 9 kV was successfully switched on (see Fig. 1 and 3). The regulation voltage was set to -2500V. Ton was set to 1.4 ms, the step width to 100 ms/V. In this configuration the voltage reached was ~-1200 V. The Ton was set to 2.1 ms, the step width to 10ms/V. The voltage reached was -1450V. The Ton was set to 2.8ms, the voltage reached was -1600V. The regulation voltage was set to -1400V. The regulation was successful with +/- 50V. Ton was set to 2.8 ms, the regulation voltage to -1600V. The regulation was successful with +/- 50V. Ton was set to 3.5 ms, the regulation voltage to -1700V. The regulation was successful with +/- 75V. Ton was set to 4.2 ms, the regulation voltage to -1900V. The regulation was successful with +/- 75V. The minimum Toff was set to 40 ms. Not much changed. The step width was set to 1 ms/V which brought the ripple of the regulation voltage down to +/- 10V. Due to a fixed upper limit in the SW of 4.2 ms Ton could not be enlarged further. This limit will be changed before day 2. After some time the drift voltage was switched on to the nominal -1000V which gave a slight decrease of the regulation voltage for less than a minute before it was back at -1900V. For the rest of the pass the system was very stable, the 24V current never exceeded 29 mA (Fig. 2), the drift voltage was stable within +/-1 V. At the end of the pass RTOF was switched off by using mode 1. No error events were generated during the whole period. The -1900V reached would suffice to operate RTOF at a drift voltage of -1000V, which is the new nominal drift voltage; however there is little margin . With a higher Ton the margin should increase. Fig. 1: Behavior of the SL_OS regulation voltage with different settings for the pulse width modulation algorithm. At approx. 17:30 [UTC] the Drift voltage was set additionally to the regulation voltage. This had only little impact to the regulation voltage, which stabilizes shortly after the Drift voltage reached the commanded value of -1000V. Fig. 2: Behavior of the LVPS currents during Day 1. The increase of the -5V current at approx. 17:30 [UTC] is due to the command of the Drift voltage. All currents show a very stable behavior without any disturbances. Espescially the +24V curr stays below 30 mA. Fig. 3: This plot shows the behavior of the SL_OS and the Drift voltage (black y-axis) in combination with the 24V curr (blue y-axis). 3.2. Day 2 The small SW patch was successfully uploaded resulting in a SW version 7.5. This patch allows using longer T_on times. The 9 kV was switched on with a set voltage for the SL_SS of -1900V, a T_on of 4.2 ms and a step op 1 ms/V. The result was a voltage of -1900 (+100/-200) V. The T_on was set to 4.9 ms, the step to 10 ms/V and the regulation voltage to -2000V. This resulted in the same voltage -1900 V, the modulation was somewhat smaller and the T_off somewhat larger. The T_on was set to 5.6 ms. This changed the regulation voltage to appr. -1950V, the T_off was longer. The step was changed back to 1 ms/V which resulted in a very stable regulation voltage of -1830 V and a T_off of 72 ms. The switch-on of the drift didn't change the regulation voltage. Going back to a step of 10ms/V resulted in a larger modulation but no change in the mean value of the regulation voltage. A setting of -1950 V to the regulation voltage did not change anything. At that time the behavior of RTOF was not understood. It was decided to put the instrument into standby and then to command the -2000V regulation voltage in one step. This was successful. The regulation voltage was at -2000V. The step was at 10 ms/V, the T_on at 5.6 ms. The cause of this behavior is in the SW which uses internally an integer number for the regulation gain instead of a floating number resulting in a value of 0 for values <1. This will be corrected in the next SW upload and will certainly make the regulation more robust. An overview of the regulated voltage SL_OS and the drfit voltage can be seen in the figure below. The drift, followed by all reflectron voltages were switched on and afterwards the storage source voltages A1, A2 and SL without problems. The voltages for the storage source were taken from the FM and did not correspond to the table values in the DPU SW. The pulser switch-on was followed by the procedure HV_step up, which unfortunately changed the source voltages to the table values. This resulted in a commanded SL_voltage which was higher than the regulation voltage. However, this did not lead to error events and could be corrected manually. The first switch-on of the filament after five years was completely nominal as well as the switch-on of the detector. All voltages and currents were nominal ll the time. The wait time after the command for the detector switch-on was however too short which lead to a ETS switch-on while the detector voltage was still being ramped up. This should be avoided in the future. The ramp-up time of the detector voltage is 3 min. With all subsystems running nominally a spectrum was taken (see below). The voltages are not yet optimized, RTOF is running at only one third of its nominal voltages, but the spectrum is quite good. The instrument is sensitive measuring spacecraft background only, the peaks are still a little bit too broad but this will get better with optimization. Switch-off of the instrument was started with commanding mode 1 (stby mode). Unfortunately again, we set the wait time too short not taking into account the low ramp-down time of the detector (3 min) causing an abrupt switch-off of the sensor with the RTOF "off" command. This should also be avoided in the future. With the spectrum the goal of day 2 has been achieved. RTOF FS storage source spectrum, background, 23. Feb. 2010, 200 s 3.3. Day 3 In principle this was a repetition of day 2 with the exception that this time he HV was regulated on the SL_SS voltage and the ortho_source channel was activated. This needed a few table uploads. The T_on was set to 6.3 ms in order to have more margin. The switch-on of the OS detector and of the OS filament was nominal and the readout of a spectrum was easily achieved. The spectrum was flat (see fig. above) which was expected due to the lower sensitivity of this channel and the non-optimized voltage settings. The mode command 513 (standard ortho_source mode) was successful and resulted in a second spectrum. The switch-off to stby yielded three error events which are understood (SW problem). The mode command from stby to mode 513 was again successful. After going to stby again mode 511 (standard storage-source mode) was successfully commanded. However, at the end of the science data readout there were a lot off error reports which shawed all zeros for a lot of HK values. This is clearly due to a HK read error and not to hardware problems. RTOF was ommanded to stby by using mode 1 which was successful without error reports. The regulated voltages SL_SS and SL_OS respectively and the drift are shown in the figure above. The goal of day 3 was achieved by being able to use mode commands successfully for both channels which is a prerequisite to use RTOF out-of passes and non-interactive. 3.4. Day 4 There was again a SW patch (V7.6) which was successfully uploaded. This SW patch corrects the Integer-floating problem mentioned on day 2 as well as the "switch to stby" errors mentioned on day 3. It also contains the voltage values used manually for the two channels and the correction for T_on (6.3 ms) . The readout error is currently dealt with a change in the database. Testing of the new SW showed that indeed these problems are now fixed. The rest of the pass was dedicated to the optimization of the voltages which became necessary due to the limited HV range. The last spectrum is shown below. The improvement compared to day 1 is clearly visible. However, the data collected on day 4 (60 spectra) first have to be analyzed in order to determine the optimal settings. No errors were reported on day 4. 3.5. Day 5 The day was dedicated to the parameter optimization of the ortho-source. Becauce there was no signal from background (see day 3) the internal gas calibration unit was used with a minimal gas flow of appr. 1.5 10-8 mbar total pressure in the ion source. At the beginning the signal was very small. However at the end of the day we had a clear spectrum of the gas mixture (see fig.). A total of 8 spectra were taken. No errors were reported. 4. Next steps - Evaluate the spectra obtained. - From the RTOF FM (lab instrument) deduce the final optimal parameter setting for both channels. This will need some time. It is expected that optimized parameters for the storage source will be available in time for the SW upload during PC12. The ortho source parameters may only be ready for upload in 2014 . - Upload optimized parameters during the SW upload in PC12 - Upload the new SW to the redundant part of the DPU in PC12 - Operate RTOF autonomously during the interference test in PC12 - Test simulataneous operation of DFMS and RTOF in space (the test in the lab as successful). - Run both DFMS and RTOF during the Lutetia flyby. - Recover most of the RTOF functionality and performance. This includes operation of both RTOF channels in order to measure cometary ions and neutrals simultaneously. For this the high voltage regulation has to be shifted to the hard mirror lense voltage. Test 5 kHz extraction in order to recover the mass range which currently terminates at 140 amu/e, but which will exceed mass/charge 300 amu/e with the lower extraction frequency. Explore the possibilities to use triple reflection for better mass resolution, at least for one channel. All these tests can be done in the lab. - Calibrate the full RTOF in the lab. 5. Anomaly reports /Cruise Phase Payload Checkout Requirements The following Cruise Phase Payload Checkout Requirements can be closed: - R_RN001 RTOF HV monitoring - R_RN002 Optimizing RTOF parameters The following associated open issue can be closed: - OI_RN001 RTOF HV discharges The following anomaly report can be closed: - SC ROSINA Internal Monitoring Triggerings during RTOF Operations State Open ID ROS_SC-86 Description During RTOF operations, the high voltages values reported in housekeeping were observed to be very inaccurate. This caused the triggering of ROSINA internal monitoring during operations. The consequence of the monitoring triggering was that the high voltages were commanded back to 0, which prevented operations of the RTOF detector. The monitoring tables had to be updated temporarely to support testing of the RTOF detector during the slot . 6. Conclusions The RTOF tests with the new software which allows the regulation of the "fixed " 9 kV converter to lower voltages were very successful. The high voltages of RTOF were on for at least 25 h without the slightest incident. All currents are nominal and stable. Especially the 24V current always stayed below 30 mA with only the HV's on. With the experience from the lab instrument in mind where the regulation has now worked for several months continuously without problems, we can state that the high voltage problem of RTOF has been solved. The only open issue currently for ROSINA on Rosetta is the test of the parallel operation of DFMS and RTOF in space which has to be verified due to the higher load of the DPU imposed by the HV regulation. Tests of parallel operations in the lab have shown no problems. This needs appr. 6h of non-interactive operation in space after the SW upload in PC12. It is expected that the performance of RTOF can be almost fully recovered to preflight values except a slight degradation in sensitivity. ROSINA Lutetia rehearsal Report for the period 14 March 2010 Table of Content 1. Purpose of test 2. Timeline 3. DFMS and COPS Background investigation 4. Anomaly reports 5. Conclusions Change Record |{{Issue}} |{{Date}} |{{Change}} |{{Responsible}} | |Issue 1 |27. Oct 2010 | |Altwegg | 1. Purpose of test The purpose of this test was to get a background baseline for the Lutetia flyby. The heliocentric distance was 1.7 AU compared to 2.5 AU for Lutetia. Apart from this the Rosetta manouvres were almost exactly the same. 2. Timeline |{{Time}} |{{Event}} |{{Remarks}} | |15:30 |Switch-on of DFMS and COPS | | |15:45 |Ion source heating | | |16:50 |GCU modes | | |17:30 |Background modes | | |20:00 |SC flip | | |24:00 |Closest approach | | |04:00 / 15. March |ROSINA off | | 3. DFMS and COPS Background investigation DFMS and COPS both showed strong signal variations with spacecraft attitude which ressembled very much what has been seen at the Steins flyby (see fig 1). This baseline will be essential to analyse the real Lutetia flyby data. 4. Anomaly reports One anomaly report was raised ID: ROS_SC-199 Corrupt science packets 5. Conclusions Background of the S/C and the payload remains an issue and will in the end probably limit the scientific results. For a flyby it is absolutely essential to have a background baseline because the outgassing varies a lot with the solar aspect angle. For the comet phase it is important to do early measurement at the comet when the comet will not yet be active in order to try to separate background from the cometary signal. ROSINA PC12 Report for the period 23. Apr.-9. May 2010 Table of Content 1. Preliminary remarks 2. Timeline 3. SW upload RN12 & RN08 4. Cover operations RN10 5. DFMS Background investigation, RN05A & RN05B 6. Ptolemy interference tests RN05C 7. Anomaly reports 8. Open tasks / CPPCR 9. Conclusions 1. Preliminary remarks Preceding PC12, 6 interactive passes were used in order to upload new SW for RTOF, to tune it and test it. This was necessary to get RTOF back to work after having observed high voltage discharges since September 2004. The corresponding report can be found under: "ROSINA RTOF activities, Report for the period, 16.Feb.-4. March 2010, RO-ROS-TR-1130". 2. Timeline Date Event Remarks 23. 4., interactive SW upload to main DPU, RN12, SW version 7.7 26. 4. out-of-pass DFMS&COPS background tests RN05A No COPS data due to a SW error, ROS_SC-200 27. 4 out-of-pass Combined test with Ptolemy, RN05C No COPS data due to a SW error, ROS_SC-200 5. 5. interactive SW patch to DPU redundant part, SW version 7.7, RN08 7. 5., interactive SW patch to DPU main part, RN12a, SW version 7.8 and RTOF cover operation RN10 SW patcht to correct ROS_SC-200, no cover operation due to a context file error ROS_SC-201 8. 5.-9. 5.,out-of-pass DFMS&COPS background tests RN05B 9. 5. , interactive SW patch to DPU redundant part, RN08a, SW version 7.8 SW patch to correct ROS_SC-200 3. SW upload RN12 & RN08 A new SW, version 7.7, was uploaded to the main DPU without problems on April 3. Subsequent operation with DFMS and COPS (RN05A and RN05C), however, showed hat no COPS HK data could be delivered any more (ROS_SC-200). This was due to timing issues induced by the RTOF HV regulation. COPS was slower than anticipated in HK-readout. An additional patch was uploaded on May 7, leading to SW version 7.8, which solved this problem. Version 7.7 was uploaded to the redundant DPU and the same patch was applied. At the end of PC12 both sides of the DPU were therefore at SW version 7.8. 4. Cover operations RN10 Due to an inconsistency in the context file after the SW patch to version 7.8 he RTOF cover operations failed (ROS_SC-201). The context file was then patched to match the actual cover position. Sequence of event: 10:36:17.695 HK Report 10:36:39.807 Execution Report of Cover Enable Command 10:36:49.789 Execution Report of Cover Position Command 10:36:50.061 Progress Event ,Unit: RTOF ,Event: PRO_R_COVER , Code: 0x1082 / 4226 ,Mode: 0x1102/ Status: 0x0085/ Number: 0x8208 Address: 0x0002FFFF, Flags: 0x60 -> Everything nominal, Motor power on, Commanded absolute position= 2, Calculated Motor relative position= -1 10:36:50.011 Sensor Error (0x20): Cov Swt TableID: 2/ LimitID: 0 ,Mode: 0x1102/ Status: 0x0080, Value: 0x559A, Exp Value: 0xBFBF, Read Value: 0x0200, lags: 01 -> Motor power still on, motor status ok, relative motor position still 0, DPU internal position wrong (<0) -> ERROR 10:36:50.163 Progress Event ,Unit: RTOF ,Event: PRO_COVCOMP ,Code: 0x0000 / 0 ,Mode: 0x0100/ Status: 0x1085/ Number: 0x20, Address: 0, Flags: 01 -> OK after error, Motor power off, relative motor position still 0 10:36:50.512 Progress Event, RTOF MonTab(62): RM_STATE8 ,SetValue: 32767/ ReadValue: 0x0000 ,Mode: 0x0100/ Status: 0x1085/ Number: 0x17Flags: 0x1C -> MC Reset error (all HK zero), due to fast Motor power on/off (within 0.5sec)?? 10:36:56.514 Sensor Error (0x15): HK Mon ,RTOF MonTab(62): RM_STATE8 , SetValue: 32767/ ReadValue: 0x0000 ,Mode: 0x0100/ Status: 0x1085, TableID: 0x1C, Value: 0, Flags: 0 -> Final MC Reset error, switch off RTOF 10:36:56:564 Progress Event, Unit: DPU ,Event: PRO_SENOFF ,Code: 0x0002 / 2 ,Mode: 0xa128/ Status: 0x0000/ Number: 0x12, Address: 0xBDC8020F, Flags: 0x0C -> RTOF off 10:36:59.666 HK Report, RTOF OFF Cause of the error: The unexpected and needless (since all parameters are ok) over error was generated because the monitoring function of RTOF cover can become active BEFORE the setup of cover operation is finally finished. This depends on the internal timing, so the error can happen but must not. This behaviour is visible also in the list of events since the error event is generated (by monitoring function) already 50ms before the progress event (generated by setup function)! Because of this, also access to the status EEPROM might happen at the same time, resulting in unexpected readings. The second error follows by using a not correctly initialized variable (cover position) to calculate the absolute position. Normally, the cover position will be correct also after a (real) error. Both errors will be fixed by a small SW patch. Both errors also occurred during lab tests on 10.05., so we can verify the correct behaviour before uploading to the spacecraft. After having applied the patch, the cover can be moved using the current context file. This requires one pass of interactive commanding before entering hibernation. 5. DFMS Background investigation, RN05A & RN05B Due to the COPS housekeeping error (ROS_SC-201) no COPS data were received during RN05A. However, DFMS worked very nicely during both slots as did COPS during the second slot. The background measurements and sensitivity determinations could be completed. 6. Ptolemy interference tests RN05C Although COPS was not working during this test due to the housekeeping problem described above, the measurement by DFMS shows a strong increase in the water density with time, again confirming the release of water as soon as part of the lander or the complete lander heats up. 7. Anomaly reports Two anomaly reports were raised: ID: ROS_SC-200 COPS HK, 1000s of sensor error reports on DOY 116/117 2010, ID: ROS_SC-201 RTOF cover operations, context file Two anomaly reports can be closed: ID: ROS_SC-86 2005-03-21 ROSINA Internal Monitoring Triggerings during RTOF Operations, solved with the SW uploads 7.4-7.7 and tested in PC12 ROS_SC-200 COPS HK, solved with the SW upload 7.8 and tested in PC12 8. Open tasks / CPPCR R_RN005 Background / OI_RN002 Background: The understanding of the source of the measured background has been greatly improved with the long duration of the mission, with the operation of RTOF and with the different opportunities given by ESOC to monitor slews and flips. Modelling of this background issue has started. This point can be closed. R_RN006 DFMS detector temperature / OI_RN010 Sensor Error due to Cold Temperature of LEDA: With the use of the non-op heaters during operations far away from the Sun the temperatures of the detector stay well above their limit . The modelling has been completed and shows a positive margin except in the case of failure of the non-op heaters. This point can therefore be closed. R_RN009 COPS microtips: this was not executed in PC12 as the microtips were executed during Lutetia rehearsal and will again be exercised during the Lutetia flyby. OI_RN010 DFMS and RTOF cover: For DFMS the cover was moved during background measurements and was successful. The cover will stay open during hibernation. For RTOF the cover was not moved (AR ROS_SC-201). This has to be done before hibernation. R_RN012 Main DPU Software Patch / OI_RN012 Main DPU Software Patch: both parts of the DPU contain SW version 7.8. A small patch is needed to correct the RTOF cover problem on both sides of the DPU. 9. Conclusions Background of the S/C and the payload remains an issue and will in the end probably limit the scientific results. This is mainly due to the high sensitivity of the sensors. However, with the extensive dataset available, a lot of the constant background can be taken into account. More critical are the effects of transient outgassing due to slews of the SC, thruster firing and payload operation. Modelling of the complete spacecraft background has started. It is mandatory that the ROSINA team knows when which instrument was operated n order to correct for this additional background. The instruments with the highest influence are probably the lander and Giada. Timelines of all instrument operations should be made easily available. Careful outgassing of all panels would be very beneficial for ROSINA. ROSINA PC12 - Interference tests Report for the 13 May 2010 Table of Content 1. Preliminary remarks 2. Timeline 3. RTOF interference tests 4. Open tasks / CPPCR 5. Conclusions 1. Preliminary remarks Preceding PC12, 6 interactive passes were used in order to upload new SW for RTOF, to tune it and test it. This was necessary to get RTOF back to work after having observed high voltage discharges since September 2004. The corresponding report can be found under: "ROSINA RTOF activities, Report for the period, 16.Feb.-4. March 2010, RO-ROS-TR-1130". 2. Timeline 13. 5., out-of-pass RTOF interference test 3. RTOF interference tests This was the first ever run test where RTOF was working autonomously. All commands were executed without fault, all science data were received. Absolutely no problems were found. 4. Open tasks / CPPCR R_RN001 RTOF HV monitoring / OI_RN001 RTOF HV discharges: With the new SW which limits the high voltage to 2 kV the discharges have disappeared. Currently there were about 40h of operation with high voltage in space and 6 months of continuous operation in the lab. We therefore are quite confident that the problem is solved and the open point can be closed. R_RN002 Optimizing RTOF parameters: Due to the late solution to the HV problem this activity has to be performed in the lab mostly. A new parameter set will be available in 2014. R_RN004 Interference test: The interferences with Giada and the lander have been assessed. This item can be closed. 5. Conclusions Background of the S/C and the payload remains an issue and will in the end probably limit the scientific results. This is mainly due to the high sensitivity of the sensors. However, with the extensive dataset available, a lot of the constant background can be taken into account. More critical are the effects of transient outgassing due to slews of the SC, thruster firing and payload operation. Modelling of the complete spacecraft background has started. It is mandatory that the ROSINA team knows when which instrument was operated in order to correct for this additional background. The instruments with the highest influence are probably the lander and Giada. Timelines of all instrument operations should be made easily available. Careful outgassing of all panels would be very beneficial for ROSINA.