urn:esa:psa:context:instrument:ro.rpcmag 1.0 1.11.0.0 Product_Context urn:nasa:pds:context:instrument:rpcmag.ro 2021-02-24 1.0 Changed inst LIDs from u:n:p:c:i:instID.scID to u:n:p:c:i:scID.instID Changed LIDs from urn:nasa:pds: to urn:esa:psa: And per "Guide toPDS4 Context Products" v1.7, changed all lidvid_reference to lid_reference urn:esa:psa:context:instrument_host:spacecraft.ro instrument_to_instrument_host Alfven, H., On the theory of comet tails, Tellus IX, 1957. reference.ALFVEN1957 Biermann, L., Kometenschweife und solare Korpuskularstrahlung, Zeitschrift fur Astrophysik, Vol.29, 274, 1951. reference.BIERMANN1951 Coates, A.J., A.D. Jonstone, B. Wilken, and F.M. Neubauer, Velocity Space Diffusion and Nongyrotropy of Pickup Water Group Ions at Comet Grigg-Skjellerup, Journal of Geophysical Research 98, No. A12, 20985-20994, 1993. reference.COATESETAL1993 Eichelberger, H.U., K. Schwingenschuh, Oe. Aydogar, and W. Baumjohann, Calibration Report RO-IWF-TR0001, Sample Rate and Frequency Response Analysis of ROSETTA RPC-MAG, IWF, January 2002. reference.EICHELBERGERETAL2002 Glassmeier, K.H., and F. Neubauer, Low-Frequency Electromagnetic Plasma Waves Comet P/Grigg-Skjellerup: Overview and Spectral Characteristics, Journal of Geophysical Research, 98, No. A12, 20921-20935, 1993. reference.GLASSMEIER-NEUB1993 Glassmeier, K.H., U. Motschmann, C. Mazelle, F.M. Neubauer, K. Sauer, S.A. Fuselier, and M.H. Acuna, Mirror Modes and Fast Magnetoacoustic Waves Near the Magnetic Pileup Boundary of Comet P/Halley, Journal of Geophysical Research, 98, No. A12, 20955-20964, 1993. reference.GLASSMEIERETAL1993 Hedgecock, P.C., A correlation technique for magnetometer zero level determination, Space Sci. Instr., 1, 83, 1975. reference.HEDGECOCK1975 Huddleston, D.E., A.J. Coates, A.D. Jonstone, and F.M. Neubauer, Mass Loading and Velocity Diffusion Models, Heavy Pickup Ions at Comet Grigg-Skjellerup, Journal of Geophysical Research 98, No. A12, 20995-21002, 1993. reference.HUDDLESTONETAL1993 Johnstone, A.D., A.J. Coates, D.E. Huddleston, K. Jockers, B. Wilken, H. Borg, C. Gurglio, J.D. Winningham, and E. Amata, Observations of the solar wind and cometary ions during the encounter bewteen Giotto and comet P/Grigg-Skjellerup, Astronomy and Astrophysics, 272, L1-4, 1993. reference.JOHNSTONEETAL1993 Motschmann, U., and K.H. Glassmeier, Nongyrotropic Distribution of Pickup Ions at Comet P/Grigg-Skjellerup: A Possible Source of Wave Activity, Journal of Geophysical Research, 98, No. A12, 20977-20983, 1993. reference.MOTSCHMANN-GLASS1993 Neubauer, F.M., The Giotto Magnetometer Experiment, ESA SP-169, 1981. reference.NEUBAUER1981 Neubauer, F.M., G. Musmann, M.H. Acuna, L.F. Burlaga, N.F. Ness, F. Mariani, M. Wallis, E. Ungstrup, and H. Schmidt, The Giotto magnetic field investigation, In: Cometary Exploration, Proc. Int. Conf. Cometary Exploration, 15-19, Budapest (Ed. Gombosi T I), 401-410, November 1982. reference.NEUBAUERETAL1983 Neubauer, F.M., H. Marschall, M. Pohl, K.H. Glassmeier, G. Musmann, F. Mariani, M.H. Acuna, L.F. Burlaga, N.F. Ness, M.K. Wallis, H.U. Schmidt, and E. Ungstrup, First Results from the Giotto magnetometer experiment during the P/Grigg-Skjellerup encounter, Astronomy and Astrophysics, 268, L5-8, 1993. reference.NEUBAUERETAL1993A Neubauer, F.M., K.H. Glassmeier, A.J. Coates, and A.D. Johnstone, Low-Frequency Electromagnetic Plasma Waves at Comet P/Grigg-Skjellerup: Analysis and Interpretation, Journal of Geophysical Research 98, No. A12, 20937-20953, 1993. reference.NEUBAUERETAL1993B Neuhaus, A., RO-IGM-SR-003, Study on the DC magnetic Requirements, System Report, IGM, 2001. reference.NEUHAUS2001 Omerbegovic, A., Radiationhardness test of 20-bit CS5508 ADC Converter for RPC MAG/ROSETTA, Diploma Thesis, F755 9530008, TU Graz, November 1999. reference.OMERBEGOVIC1999 Othmer C., and I. Richter, RO-IGM-TR-0003, Fluxgate Magnetometer Calibration for Rosetta: Analysis of the FM Calibration, Institut fuer Geophysik und Meteorologie, Braunschweig, Oktober 2001. reference.OTHMER-RICHTER2001 Richter I., and E. Cupido , RO-RPC-UM, Rosetta Plasma Consortium: User's Manual, Institut fuer Geophysik und extraterrestrische Physik, Braunschweig, December 2011. reference.RICHTER-CUPIDO2011 Richter I., and M. Rahm, RO-IGM-TR-0002, Fluxgate Magnetometer Calibration for Rosetta: Report on the FM and FS Calibration, Institut fuer Geophysik und Meteorologie, Braunschweig, Oktober 2001. reference.RICHTER-RAHM2001 Schmidt, H.U., and R. Wegmann, Plasma flow and magnetic field in comets, In: Comets (Ed. L.L.Wilkening), University of Arizona Press, 538-560, 1982. reference.SCHMIDT-WEGMANN1982 Sulivan, J., The building and operation of the MAG_FPGA In the Fluxgate Magnetometer Electronics, KFKI RMKI, Budapset, 2001. reference.SULIVAN2001 Tsurutani, B.T., and E. Smith, Hydromagnetic waves and instabilities associated with cometary ion pickup: ICE observations turbulence asociated with comet Giacobini Zinner, Geophys. Res. Lett.,13, 1986. reference.TSURUTANI-SMITH1986 Wallis, M.K., Weakly shocked flows of the solar wind plasma through atmospheres of comets and planets, Planet. Space Sci., 21, 1647-1660, 1973. reference.WALLIS1973 Winske D., C.S. Wu, Y.Y. Li, Z.Z. Mou, and S.Y. Guo, Coupling of newborn ions to the solar wind by electromagnetic instabilities and their interaction with the bow shock, J. Geophys. Res., 90, 2713-2726, 1985. reference.WINSKEETAL1985 Wu, C.S., and R.C. Davidson, Electromagnetic Instabilities produced by Neutral-Particle Ionization in Interplanetary Space, J.Geophys.Res., 77, 5399, 1972. reference.WU-DAVIDSON1972 ROSETTA PLASMA CONSORTIUM - FLUXGATE MAGNETOMETER Magnetometer not applicable not applicable Instrument Overview =================== The ROSETTA orbiter magnetometer (RPCMAG)is part of the ROSETTA Plasma Consortium (RPC) set of Scientific instruments. The purpose of the magnetometer is the measurement of the interplanetary magnetic field close to different targets visited by the ROSETTA spacecraft. Science Objectives of the Investigation ======================================= + Measurements of the interplanetary magnetic field during the flybys at planet Mars & Earth, the asteroids and in the environment of comet 67p/Churyumov-Gerasimenko. + Study of the structure and dynamics of the cometary-solar wind interaction region. + Study of the generation and evolution of the cometary magnetic Cavity. + Study of cometary tail evolution and structure. The Cometary Magnetic Field - A historical perspective ====================================================== In 1951 the German Astronomer Ludwig Biermann used the fact that cometary tails are always pointing away from the Sun to postulate the solar wind. It was Hannes Alfven who suggested in 1957 that cometary tails are due to the draping of the interplanetary magnetic field around the cometary nucleus. To explain this draping effect C.S. Wu and R.C. Davidson in 1972 studied the pick-up of cometary ions and the associated mass loading of the solar wind. Associated strong plasma wave turbulence due to this mass loading was first detected by B.T. Tsurutani and E.J. Smith in 1986. The magnetic field draping itself was first measured by F. M. Neubauer and co-workers using magnetic field measurements made onboard the GIOTTO s/c. The ROSETTA Orbiter Magnetic Field Instrument ============================================= + Fluxgate-Magnetometer with a resolution of at least 40 pT + 2 Sensors OB/IB + 20 Bit ADC + Measuring B-Field in 3 components with a max. vector rate of 20 Hz + The Fluxgate Magnetometer RPC-MAG performance parameters are in full accordance with the EID-B design goals. + The Outboard/ Inboard sampling rate can be inverted by command either for higher Inboard time resolution or in case of outboard failure. + The sensors are fully calibrated also versus a wide temperature range. The temperature at Outboard and Inboard sensor is monitored in MAG housekeeping data. FGM Classification =================== + Saturated-Core-Magnetometer + Vector measurements possible + No absolute measurements + Lightweight, compact construction + Low power consumption + Qualified for space applications RPC-MAG FGM Characteristics ============================ Mass (sensor): 45 g Volume (sensor): 23 cm^3 Mass (electronics): 336 g Mass (harness H10): 109 g Mass (harness H11): 55 g Power: 840 mW @ 28V Operation interval: 15 years Sampling: 20 vectors/s Bandwidth: 0 - 10 Hz Resolution: +-0.031 nT Dynamics range: +-16384 nT Conversion: 7 * 20Bit ADC Temperature Range: operating: -160 ... +120deg C non-operating: -180 ... +150deg C Flight Unit Components ====================== DPU: FS IB-Sensor: FM OB-Sensor: FM Major Operational Constraints ============================= + RPC-MAG has to be operational as long as power is available + RPC-MAG has a joint operational requirement with ROMAP, especially during the lander descent. + RPC-MAG has a requirement on Spacecraft Magnetic Cleanliness of 25nT at the OB sensor. According to the performed continuous magnetic mappings of all units and s/c magnetic system modelling the expected magnetic field at the OB sensor is about 45nT (without boom motor field). + MAG will see some stray fields from other units like: Reaction Wheels, Solar Panel Motor and Thruster firing. This needs to be monitored during flight, especially during switch on procedures, for purposes of inflight calibration. History of the Instrument - Design Changes ========================================== The magnetometer experiment came on board of ROSETTA in a very late phase of the project. For this reason the mechanical (mass) and electrical requirements (power) were extremely stringent: mass below 1kg, power below 1W! In addition the project mass budget went negative after few months so that the project had to run general descoping actions to reduce mass. The first mass reduction action did not safe enough mass, so a second run had to be made. This led to severe descopings on the magnetometer sensors and electronics whose mass was already in the margin of the other experiments: Actions: + reduce size and mass of sensor, + integrate small micro-D connector into sensor: as a result the MAG sensors are extremely small and have low mass of 36g ! But due to this no access to tune the inner ring-cores for low offset was possible anymore. + The electronics board was reduced by 30% in size (from 1.5 boards to 1 board only) and down to 1.5mm thickness of the big multilayer board by higher integration. Connectors had to be changed from cannon-D to micro-D. The higher integration and size reduction was reached by new very dense layout and deletion of offset temperature compensation circuit for all 6 sensor-axes ! This mass saving action later on during qualification (vibration of RPC-0) resulted in a dramatic failure of the MAG board where both ASICS (128 pins)lost several pins due to very high resonance peaks of the multilayer board. The rework and redesign took several weeks and could only be solved by increasing the stiffness of the board by adding (gluing) additional stiffeners on top and bottom side of the board thus adding several 100g of mass. Comment: at this stage of the project the launcher has changed from ARIANE 4 to 5 giving more mass for ROSETTA. FGM Location ============= Sensors : on Boom 1.5 m away from s/c to minimize s/c generated noise/disturbances. Distance between Sensors : 15 cm 2 sensors for redundancy and to eliminate residual noise from s/c. Electronics: inside s/c in RPC-0 Box, common box for ALL RPC electronics. MAG Sensor - History ==================== The prototype of the ROSETTA FGM-sensors have been successfully flown onboard the DS-1 s/c. Design Changes: Due to the extreme boom temperature it became necessary to change the MAG sensors baseplate from isolating Glassfibre to Carbonfibre which has a much better thermal conductivity in order to get rid of the internal 25mW drive power for each sensor. Without this change, each sensor would heat up much higher then expected. MAG Sensor: Characteristics =========================== Excitation Coil: 1 layer CuL, completely wounded on ring core Core material: Permalloy (Fe19Ni81) Pickup Coil: 2*129 windings in 6 layers, 0.112 mm - High Temp. CuL Bobbin: Macor + glass ceramic + Ease of machining + maximum use temperature 800 deg C. + low thermal conductivity (1.46W/mK) + high temperature insulator (0.79kJ/kgK) + excellent electrical insulator (>10^16 Ohm/cm) + zero porosity (0%) + no outgassing in ultra high vacuum + strong and rigid + Coefficient of expansion: 7.4 x 10^-6/K Housing: Lexan + Polycarbonate + Excellent impact strength + Good weatherability + Ease of machining + Thermoformability + UV resisting + flame retardancy + light transmittance 86 % + high thermal insulation MAG Sensor: Features ==================== Sensor body consists of MACOR which has a smaller thermal Coefficient of expansion (7.4 x 10^-6/K) in comparison to the Copperwire (17 x 10^-6/K) of the windings. As the copperwires are wound so tight on the MACOR body, the thermal Expansion of the copper does not play a role any more. Both sensors are equipped with a temperature sensor PT1000 inside the housing to measure the sensor temperature. A/D Converter CS5508 and Radiation Hardness =========================================== The ADC Crystal CS5508 was chosen by the Space Research Institute in Graz because of its good performance characteristics: + 20-Bits + very low power 3.72 mW + on chip self-calibration circuitry + extended temperature range. The radiation behavior of the ADC was unknown. IWF Graz bought a special lot of this component and performed tests by using the facilities at ESTEC to determine the amount of radiation the converter could withstand and still remain within specification. The CS 5508 total dose tolerance was found to be 27 krad. The devices showed high susceptibility to the Single Event Upset (SEU) as well as to the Single Event Latch-up (SEL). Additional Tantalum Metal Sheet (0.5mm) was used to shield the ADCs against irradiation during the mission period! (comment: Tantalum is used because only mass saves from total dose radiation, Tantalum has a specific density of 16.6g/cm^3!. It must be mentioned that the glue of heavy Tantalum shields on top of each ADC chip causes additional stress on the chip pins during vibration, therefore the Tantalum spot shield is also glued to the board on each small side.) For detailed information refer to the document: RADIATIONHARDNESS TEST OF 20-bit CS5508 ADC CONVERTER, for RPC MAG/ROSETTA, Diploma Thesis, Amira Omerbegovic, F755 9530008 TU Graz, November 1999. RPCMAG Frequency Plan ===================== RPCMAG needs 3 different frequencies which can all be derived from a single 4.194304 MHz oscillator by appropriate division within the FPGA: FGM: excitation signal 50 kHz & 12.5 kHz 4.194304 MHz / 84 = 49.93219 kHz => 12.63345 kHz The division is achieved by 84 = 26 +24 + 22 ADC: drive frequency 32.768 kHz 4.194304 MHz / 128 = 33.768 kHz Device clock for 1355 transceiver PIU I/f: 400 kHz +- 10% 4.194304 MHz / 10 = 419.439 kHz Assumptions: Environmental ========================== + Power supply: Supply Voltage provided by PIU has to be stabilized within a 1% range + Temperature: Temperature changes are taken into account by the calibration + Radiation : The ADCs are shielded by Tantalum plates (thickness: 0.5 mm) Single Event Upsets (SEU) These effects cause bitflips in memories, it can be protected by failure correction algorithms (Hamming code) or redundancy. For MAG an SEU event is uncritical because of full redundancy and because a bitflip will cause the loss of one or few vectors which can be tolerated. Single Event Latch Up protection (SEL). It was decided by the RPC team to have the latch up protection (due to shortage and therefore overcurrent in some circuitry). The circuitry is built from SEL immune parts in the central RPC power unit, which in case of an SEL measures the overcurrent (LCL) and turns off RPC within msec. Restart has to be commanded. Assumptions: Contingencies ========================== Critical parts: + Every component has to be alive for a successful operation of the FGM + The ADCs are shielded by Tantalum plates + PCB located in RPC-0 for shielding + LCL protects electronics against short-circuits (located in PIU) Possible MAG problems during flight are covered by the RPC-0 FMECA (Failure Mode Effectiveness and Criticality Analysis) Assumptions: Redundancies ========================= + 2 sensors + No redundancy for electronics Design Margins ============== The electronics design margins are standard workmanship questions for space application. Applicable to each part, especially capacitors.The design, therefore has been made according to ESA Standards as described in their documentation. Critical parts are the: + ADC CS5508 wrt. Radiation (see above) + MAX 400 Op Amp which is not on the preferred parts list of ESA or NASA, because it is not qualified yet. However, this part is used in commercial industry since years in great numbers and thus showing and demonstrating the quality level and reliability. Operations =========== The RPCMAG instrument has only two intrinsic modes: + ON + OFF After power on reset, the MAG instrument calibrates itself and starts to send continuously 20 Hz Magnetic field (B) and Housekeeping (HK) Data. Filtering is done in the PIU. MAG Instrument Software ======================= MAG software runs in a radiation hard 1280 FPGA! Detailed description of the ACTEL FPGA software can be found in the following document: The building and operation of the MAG_FPGA in the Fluxgate Magnetometer Electronics. RPCMAG has no individual s/w. It has only the capability to be switched on/off and later it runs in continuous 20 Hz sampling mode. Calibration of the ADCs once in every 24 hour. It only samples and sends 20 Hz data (6 vectors + 1 HK). All other operation is done in PIU-S/W. A RPCMAG Data Acquisition Cycle : Using a crystal oscillator the MAG FPGA sends a 'StartConvert' signal (CONV)to the ADCs at a certain time. After all ADCs have been finished the conversion (RDY Signal) the data will be read and transmitted to the Link FPGA. As the 20 Hz of the MAG unit is slightly different from the 20 Hz at the s/c there will be not an integral number of vectors in an RPC AQP. Therefore, the CONV signal is passed to the Link chip (CONV1) to send a signal to the PIU. PIU will then generate a high res time stamp for the first vector of the packet. The accuracy is better then 1ms +- 100 us. MAG Software in PIU ==================== PIU is just an observer. It has no control of what MAG is doing. The MAG S/W in the PIU has the task to + synchronize itself with the MAGs internal conversion signal + sample all 20 Hz Mag data without any loose and store on board time for the first value of the packet + prepare science and HK packets for transmission + filter the 20 Hz data to an appropriate mean value and set MAG to the right SID + switch the desired sensor to be primary + handle FCPs for MAG + provide HK values, measured by the MAG ADC, for PIU, MAG, MIP Mode description: ================= MODE SAMPLE PACKET PACKET VECTOR RATE PERIOD LENGTH RATE Minimum Mode SID1 1/32 Hz 1024 s 32 Pri Vec 0.03125 vec/s 1 Sec Vec 0.000976 vec/s Normal Mode SID2 1 Hz 32 s 32 Pri Vec 1 vec/s 1 Sec Vec 0.03125 vec/s Burst Mode SID3 20 Hz 16 s 320 Pri Vec 20 vec/s 16 Sec Vec 1 vec/s Medium Mode SID4 5 Hz 32 s 160 Pri Vec 5 vec/s 1 Sec Vec 0.03125 vec/s Low Mode SID5 0.25 Hz 128 s 32 Pri Vec 0.25 vec/s 1 Sec Vec 0.007812 vec/s Test Mode SID6 20 Hz 16 s 320 Pri Vec 20 vec/s 1 Sec Vec 0.0625 vec/s HK Mode 32 s 8 words 0.03125 vec/s Filter S/W =========== Burst data (SID3) pass the s/w unfiltered. Data of all other modes will be filtered in a multi stage process. Each stage filters and decimates the data in time. The data fields in the HK packet filtercfg stageAId stageBId control the filter mode. MODE SAMPLE FILTER IDs SAMPLES PER PACKET RATE STAGE 1 STAGE 2 STAGE 3 PRIMARY SECONDARY Minimum SID1 1/32 Hz 4 3 3 32 1 Normal SID2 1 Hz 1 2 off 32 1 Burst SID3 20 Hz off off off 320 16 Medium SID4 5 Hz 2 off off 160 1 Low SID5 0.25 Hz 4 3 off 32 1 Test SID6 20 Hz TC def. off off 320 1 Time Stamps of Data Packets ============================ Due to this complex filtering process the time stamps of the measured data are different for each mode. Each vector coming out of the PIU gets a specific time stamp according to the actual mode. These time stamps are shifted towards the real time of the physical event. The time stamps of the data lie BEFORE the real measurement time. This time displacement for the PRIMARY vectors in different modes is listed in the following table: MODE SAMPLE RATE TIME SHIFT (PRIMARY VECTORS) Minimum SID1 1/32 Hz 223.7 s Normal SID2 1 Hz 8.2 s Burst SID3 20 Hz 0 s Medium SID4 5 Hz 1.35 s Low SID5 0.25 Hz 27.7 s Thus, the true time of the physical event is achieved by adding the listed time shift to the time stamp of the vector. For the SECONDARY vectors a different time stamping applies. As the SECONDARY vectors are not filtered but just picked out of the data stream. Thus, the first SECONDARY vector of a packet is stamped with the time of the end of the data packet. Therefore, the following shifts have to be taken into account: MODE SAMPLE RATE TIME SHIFT (SECONDARY VECTORS) Minimum SID1 1/1024 Hz 1023.95 s Normal SID2 1/32 Hz 31.95 s Burst SID3 1 Hz 15.95 s Medium SID4 1/32 Hz 31.95 s Low SID5 1/128 Hz 127.95 s The archive data in the datasets labeled with V1.0 use the original times tamps. For later datasets labeled V2.0 and above the time stamps of the PRIMARY vectors have been corrected by the archive generation software. The SECONDARY vector time stamps, however, stay always as they were originally transmitted in the telemetry. Sensors extreme Temperature Tests ================================= The MAG sensors on the boom will see extreme Temperatures from -200 deg C to +150 deg C. This Temperature range for the sensors could only be tested in the Cryo-Mumetal chamber of Garchy (France), where the Magnetic field is completely shielded by Mumetal. A non Magnetic Test Table inside can be cooled by liquid Nitrogen to -191 deg C. This test was performed successfully with all sensors in January 2001. The extreme temperature range was predicted for comet Wirtanen orbit, a new prediction for the CG target does will probably be similar. In Magnetsrode the positive temperature range was tested & calibrated up to +75 deg C. However, it is impossible to test the sensors in non magnetic environment and thermal Vacuum, no facility for this exists worldwide. EMC Test ======== The magnetic field is more or less distorted by the following s/c units: Reaction wheels Solar Arrays (<0.5 nT) SADM (23 nT) Lander Thrusters (compensated) Calibration =========== The magnetometer has been calibrated on ground in the magnetic coil facility MAGNETSRODE at Braunschweig, Germany. This facility is operated by the Institute of Geophysics and extraterrestrial Physics. The complete calibration is documented in the following documents: Report: RO-IGM-TR-0002 DC-Analysis: RO-IGM-TR-0003 AC-Analysis: RO-IWF-TR-0001 Step by Step Calibration Procedure: RO-IGEP-TR-00028 Nominal (uncalibrated) Conversion of Digital values =================================================== 1)Science Data: Magnetic field values (range = +-15000nT , 20 Bit): B_max = +15000 nT B_min = -15000 nT counts = 2^20 = 1048576 Nominal_Factor = (B_max - B_min) / counts The binary values of the 20 bit ADC Output are in the range of 00000h : FFFFFh corresponding to decimal values of 0 : (counts-1) As the ADC is operated in bipolar mode the nominal relation between counts and magnetic field is as follows: 00000h <-> B_min 80000h <-> 0 FFFFFh <-> B_max The conversion routine from binary TM data to ASCII Rawdata converts the binary values to signed integers in the following way 00000h -> -counts/2 80000h -> 0 FFFFFh -> +counts/2 These signed integers in the range from -counts/2 to +counts/2 are the EDITED RAW DATA.Unit is [counts]. To convert these into uncalibrated [engineering, enT] nanotesla values, the following algorithm is applied: B= [ADCvalue + counts/2] * Nominal_Factor + B_min [enT] Also the Housekeeping Reference Voltage is monitored via a 20bit ADC and converted in the same manor. 2)Housekeeping Data: Magnetic field values (range = +-15000nT, 16 bit) B_max = +15000 nT B_min = -15000 nT counts = 2^16 = 65536 Nominal_Factor = (B_max - B_min) / counts The binary values of the 16 bit ADC Output are in the range of 0000h : FFFFh corresponding to decimal values of 0 : (counts-1) As the ADC is operated in bipolar mode the nominal relation between counts and magnetic field is as follows: 0000h <-> B_min 8000h <-> 0 FFFFh <-> B_max The conversion routine from binary TM data to ASCII Rawdata converts the binary values to signed integers in the following way 0000h -> -counts/2 8000h -> 0 FFFFh -> +counts/2 These signed integers in the range from -counts/2 to +counts/2 are the EDITED RAW DATA.Unit is [counts]. To convert these into uncalibrated [engineering, enT] nanotesla values, the following algorithm is applied: B= [ADCvalue + counts/2] * Nominal_Factor + B_min [enT] 3)Housekeeping Data: Voltages (range = +-5V, 16 bit) V_max = +2.5 V V_min = -2.5 V counts = 2^16 = 65536 Nominal_Factor = (V_max - V_min) / counts The binary values of the 16 bit ADC Output are in the range of 0000h : FFFFh corresponding to decimal values of 0 : (counts-1) As the ADC is operated in bipolar mode the nominal relation between counts and magnetic field is as follows: 0000h <-> V_min 8000h <-> 0 FFFFh <-> V_min The conversion routine from binary TM data to ASCII Rawdata converts the binary values to signed integers in the following way 0000h -> -counts/2 8000h -> 0 FFFFh -> +counts/2 These signed integers in the range from -counts/2 to +counts/2 are the EDITED RAW DATA.Unit is [counts]. To convert these into voltages, the following algorithm is applied: U= [ADCvalue + counts/2] * Nominal_Factor + V_min [V] Also the nominal temperatures are computed from HK voltages in a similar way Some voltage are monitored as 8bit values; the conversion, however, is done in the same way. Magnetic Cleanliness ==================== Details can be found in IABG: B-TR40-0555 RO-IGM-SR-0003 Output data =========== FGM output is: + Time series of 3 B-Field vectors from the IB-Sensor + Time series of the IB-Sensor Temperature + Time series of 3 B-Field vectors from the OB-Sensor + Time series of the OB-Sensor Temperature + Additional HK values for PIU & MIP The RPC MAG-CREW ================ PI: Glassmeier, Karl-Heinz, IGEP,TU-BS TM: Richter, Ingo, IGEP, TU-BS Research Assistant: Diedrich, Andrea,IGEP, TU-BS, died in 2007 Instrument Development: Kuhnke, Falko,TU-BS (electronics & sensor) Musmann,Guenter,TU-BS (sensor) Stoll, Bernd, IGEP,TU-BS (electronics & sensor) Co. Pfeil/Trawid, Hildesheim (sensor) Aydogar,Oezer,IWF,TU-GRAZ (electronics) Conversion Software Development Hans Eichelberger, IWF,TU-Graz Co-Is: Auster, Hans-Ulrich, IGEP,TU-BS (PI of the ROMAP FGM) Balogh, Andre, IC, London Coates, Andrew J., MSSL Cowley, S.W.H., Univ. Leicester (science planning & analysis) Flammer, K., UCSD (science planning & analysis) Gombosi, Tamas,Univ.of Michigan (cometary science support) Horanyi, M.,Univ. of Colorado (plasma-dust interact.) Jockers, Klaus, MPS Lindau (ground based observations) Kuerth, Eckehard, DLR, Berlin (comet. nucleus physics) Ip, W.-I., MPS, Lindau (Science) Mehlem, Klaus, ESTEC (magnetic cleanliness) Motschmann, Uwe,ITP, TU-BS (science planning & analysis) Musmann, Guenter, IGEP, TU-BS (ex RPC-TM) Neubauer, Fritz, Univ. Cologne) (overall science support) Richter, Ingo, IGEP, TU-BS (MAG TM, calibration,analysis) Rustenbach, Juergen, MPE-Berlin,(Co-I of ROMAP FGM) Sauer, Konrad, MPE-Berlin (theory and simulation) Schwingenschuh, Konrad, IWF-Graz(magn. cleanl.,science) Szegoe, K.,RMKI-KFKI,Budapest Tsurutani, Bruce, JPL, Pasadena (science planning & analysis) Zang, Gary,Bart.Res.Inst,Delaware(science planning & analysis) Acronyms ======== ADC: Analog-Digital-Converter AQP: Acquisition Period ASIC: Application Specific Integrated Circuit B-FIELD: Magnetic Field CG: 67P/Churyumov-Gerasimenko CO-I: Co-Investigator CuL: Kupferlackdraht, Enamelled copper wire DDS: Data Distribution System DPU: Digital Processing Unit DS-1: NASA's Deepspace 1 Mission EAICD: Experimenter to Archive Interface Control Document EID-B: Experiment Interface Document , Part B EMC: Electromagnetic Compatibility ESA: European Space Agency ESTEC: European Space Research and Technology Centre FGM: Fluxgate-Magnetometer FM: Flight Model FMECA: Failure Mode Effects and Criticality Analysis FPGA: Field programmable Gate Array FCP: Flight Control Procedure FS: Flight Spare Model HK: Housekeeping data (Supply voltages, Ref. voltages, Temperatures) H/W: Hardware IABG: Industrieanlagenbetriebsgesellschaft IB: Inboard Sensor ID: Identifier I/F: Interface IGEP: Institut fuer Geophysik und extraterrestrische Physik, TU-Braunschweig IWF: Institut fuer Weltraumforschung,Graz LCL: Latching Current Limiter LEXAN: Polycarbonate resin thermoplastic MACOR: Machinable glas ceramic MAG: Magnetometer MIP: RPC Mutual Impedance Probe NASA: National Aeronautics and Space Administration OB: Outboard Sensor OPAMP: Operational Amplifier PCB: Printed Circuit Board PDS: Planetary Data System PERMALLOY: Nickel Iron magnetic alloy PI: Principal Investigator PIU: RPC Power Interface Unit PSA: Planetary Science Archive PT1000: Platinum Thermistor with 1000 Ohm nominal resistance RAW: Data in units of ADC counts in instrument coordinates ROKSY: ROSETTA Knowledge Management System ROMAP: ROSETTA Lander Magnetometer RPC: ROSETTA Plasma Consortium RPCMAG: ROSETTA Orbiter Magnetometer RPC-MAG: ROSETTA Orbiter Magnetometer RPC-0: RPC Main Electronics Box SADM: Solar Array Drive Mechanism S/C: Spacecraft SID: Science Mode Identifier S/W: Software SEU: Single Event Upset SEL: Single Event Latch-up TC: Telecommand TM: Telemetry TM: Technical Manager TS: Time Series UV: Ultraviolet us: microsecond Wrt.: with respect to References ========== Alfven H 1957, On the theory of comet tails, Tellus, 9, 92-96. 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