ROSINA PC10 Report for the period 21.-28. Sep. 2009 Table of Content 1. Timeline 2. Consert Interference Test with COPS 3. SW upload RN12 & RN08 4. Cover operations RN10 5. DFMS Background investigation, out-of pass and interactive RN05A & RN05B 6. Giada interference test RN04A 7. Lander interference test RN04B 8. Combined measurements with Ptolemy RN04C 9. COPS microtips 10. Anomaly reports 11. Open tasks / CPPCR 12. Conclusions 1. Timeline Date Event Remarks 21. 9., out-of-pass Interference test with Consert 21. 9., interactive SW upload to main DPU, RN12 21. 9., interactive Cover operations RTOF and DFMS, RN10 21.9.-22.9., out-of-pass DFMS background investigation, RN05A 22.9., interactive DFMS optimizing, RN05B 22.9.-23.9., out-of-pass Interference with lander, RN04B 23.9 -24.9., out-of-pass COPS microtips 24.9 -25.9., out-of-pass Combined measurements with Ptolemy, RN04C Ptolemy shut off after 10 min. 25. 9., interactive DFMS optimizing, RN05B 28. 9., interactive DFMS optimizing, RN05B 28. 9., interactive SW patch to DPU redundant part, RN08 2. Consert Interference Test with COPS COPS was switched on with both gauges. The sensor worked nominally. 3. SW upload RN12 & RN08 A new SW, version 7.2, was uploaded to the main DPU without problems. At the end of the ROSINA activities the redundant DPU was patched. This led to a loss of the time synchronization. An anomaly report was raised (AR 4. Cover operations RN10 Because the SW upload went very smooth the cover operations were performed on the same day without any problems. 5. DFMS Background investigation, out-of pass and interactive RN05A & RN0 So far, there was a mismatch between DFMS background and COPS pressure measurements. This mismatch could be solved with the measurements performed. Some voltages were retuned (which is very time consuming), but with the current settings we now have a very good understanding of the DFMS characteristics. DFMS is much more sensitive than it was before launch, it even surpasses the value given in the proposal, which of course is excellent, but which also makes DFMS very sensitive to "unwanted" background (see e.g. interference test with Ptolemy). Some problems with the PDOP's showed that this kind of commanding is demanding. Thanks to Sylvain Lodiot all problems could be solved in real-time. During the retuning of the DFMS an error report and some unexpected progres reports were transmitted. These are due to timing issues between DFMS and the DPU. 6. Giada interference test RN04A Fig. 2: COPS pressure measurements during Giada operation (blue) and during DFMS background measurements (brown). All operations were nominal. Fig 2 shows clearly that the pressure measured at COPS is higher by a factor of 4 if Giada is operated. The decrease at the beginning is due to outgassing of the COPS nude gauge after switch-on. This confirms the measurements made during PC8, interference scenario. 7. Lander interference test RN04B During lander switch-on on Sep 23, 00:00:00 COPS monitored the pressure (see fig. 1). The first peak is due to the outgassing of COPS itself after switch on. A pressure increase was measured starting shortly after lander switch-on. The pressure increase was about a factor of 2 compared to the normal value of 2 10-11 mbar measured by COPS if undisturbed and it decreased again after about 3 hrs but stayed above the background value for the rest of the time. This confirms that the lander is a source of additional background if heated, be it by the Sun as in February 09 during the thermal characterization, be it through operation of the lander. 8. Combined measurements with Ptolemy RN04C DFMS and COPS were both switched on in order to see the effect of the Ptolemy operation in the background (operation with release of Helium) and also in order to measure the water background simultaneously with Ptolemy. For ROSINA all operations were nominal. In Fig. 3 the partial water pressure measured by DFMS is shown as a function of time. The switch-on of Ptolemy is marked by a red line. Shortly afterwards the pressure increases, probably due to Ptolemy heating up. Unfortunately Ptolemy was shut off after ca. 10 min. due to overcurrent. The pressure decreased again after Ptolemy shut-off. The increase later on is due to a temperature increase in the DFMS ion source which is not corrected. 9. COPS microtips This operation was successful. An error in the OIOR (wrong mode number) led to a sensor error. The operation continued unperturbed. 10. Anomaly reports One anomaly report was raised: ID: ROS_SC-180 PC10 RN SW patching and loss of time synchonisation One anomaly report can be closed: ID: ROS_SC-166 RN DFMS switch OFF during Steins flyby 11. Open tasks / CPPCR R_RN004 Interference test: There is a clear interference between Giada operation and measured background pressure. It is mandatory that it is known to the ROSINA team when Giada is operating and when it is shut off in order to correct for this additional background. The issue can be closed. R_RN005 Background: The understanding of the source of the measured background has been greatly improved with the different interference measurements and the thermal characterization of the SC in Feb 09. Modelling of this background issue has started. The parameters found for DFMS allow now a direct comparison between the two instruments. The measurement with DFMS and COPS should continue whenever there is a special occasion, e.g. during PC12 and during test runs for the Lutetia flyby. During the Lutetia flyby S/C flips should be done well in advance to the encounter. If possible a period of outgassing of the -X panel (lander) should be performed before Lutetia. R_RN006 DFMS detector temperature: the detector temperature behaviour has now been understood thanks to extensive modelling efforts and thanks to enough data at different SAA and solar distances. The change in procedure (non-op heater switch-off manually) works perfectly and leads to temperatures well within the limits. The SW bug which caused the LEDA heater to switch-off has been corrected in the new SW version 7.2. This issue can be closed. There should be no problem for DFMS during hibernation. Care has to be taken when operating DFMS after the hibernation at large heliocentric distances. Enough time has to be allowed for the detector to warm up in stby before operation begins. OI_RN003 Detector temperature and OI_RN010 Sensor Error due Cold Temperature of LEDA can be closed. R_RN009 COPS microtips: this operation was successful. Has to be repeated in PC12. OI_RN009 RN COPS Microtips Sensor Error can be closed. R_RN010 DFMS and RTOF cover: this operation was successful. Has to be repeated in PC12. R_RN012 Main DPU Software Patch: both parts of the DPU contain SW version 7.2. In order to upload the parameters found for the DFMS operation a small SW patch has to be performed latest in PC12. No attempt was made to operate RTOF except the cover operation. Currently a new SW is developped and will be tested in the next weeks which should cure the partial discharge problem of RTOF by lowering the HV's. It is expected that with this change RTOF will run stably. However, in order to implement this SW and to test it in space a test period of ca. 6 6h passes will be needed, preferably early next year before the signal travel time gets too long. 12. 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. 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. Careful outgassing of all panels would be very beneficial for ROSINA. ROSINA COPS operation during Pressurization tests Report for the period 25.-29. Oct. 2009 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. 1 COPS pressure measured with the nude gauge. The two peaks seen are limited (saturation) in height, the real pressure was larger than 10-8 mbar. The two arrows indicate the times when a new offset measurement was made (every 24h) which changes the pressure slightly. The data shown have a time resolution of 1 min. Data with 2 s resolution are available upon request. 2. Conclusions Apart from the two peaks (which we assume were thruster firings) the pressure remained constant. A few small pressure increases may be due to switching on/off of SC subsystem or a change in SAA.