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ESA EJSM/JGO Radio & Plasma Wave Instrument (RPWI) Warsaw meeting 110110 Lennart Åhlén Radio & Plasma Wave Instrument (RPWI) Principle Block diagram Power consumption Xilinx, mW (100%) Actel, mW (100%) % On time Xilinx, mW Actel, mW LP-PWI (preamp) 400 400 0,8 320 320 SCM (preamp) 400 400 0,8 320 320 RWI (preamp) 300 300 0,5 150 150 RA-PWI (preamp) 200 200 0,1 20 20 MLA (preamp) 300 300 0,05 15 15 MIME (drivers) 800 800 0,1 80 80 Bias + MIME 1200 1500 0,8 960 1200 LF 1000 2000 0,8 800 1600 MF 1000 1500 0,25 250 375 HF 1700 1700 0,5 850 850 DPU 2800 1000 1 2800 1000 Total 10100 10100 6565 5930 With 85% DCDC 11918 11918 7747 6997 Mass: 6.8kg Harness 1kg Cosmic Vision Instrumentation ASIC The activity will be kicked off 17th of September with a Spanish consortium involving Arquimea, CSIC, UPC and the University Carlos III. Main box mechanics •Backplane with power distribution, analog and digital interfaces •Board size: 20x15cm •Connectors: Micro-D type •Box : 21x16x12 cm. •Distance between Boards: 20mm RPWI Grounding block diagram EMC. MIL-STD-462D ECSS-E-ST-20-07C(31July2008) RO-EST-RS-3001/EIDA Conductive and radiation emission requirements EMC requirements 1. 2. 3. 4. 5. 6. Oscillator controlled DC/DC converters. To minimize magnetic stray fields from DC/DC converter transformer and coil toroid cores should be used. Motor magnetic circuits should be balanced in order to minimize stray field variations synchronic to the rotation. Motor brushes should be filtered in order to minimize voltage and current spikes. SCM and the flux gate magnetometer (MAG) sensors should be separated by a minimum of 0.3 meter, and recommended 0.5 meter. The MAG harness has to be placed at least 8 cm from the SCM sensor. Radiation protection •Spot shielding should be used for all S/C external electronics •Box and spot shielding should be used for the RPWI Box •Use of Rad Hard components •Box shielding 10mm •2 kg extra mass needed for 8mm box protection •3kg allocated by ESA for radiation shielding of RPWI Action: Calculations of internal box radiation levels using GEANT 4 LP-PWI Bias control, LF wave analyzer and MIME HFwave analyzer WHY Should we use the ESA ASICs ? •They are guarantied Rad hard •ESA will do the paper work •ESA will pay for the qualification •We will save mass (up to 650g) •We may save power that can be used for signal processing •We may save money •We can convert saved mass into antenna length •If they are not delivered in time we blame ESA for the delay RA-PWI, RWI and LP-PWI Preamplifiers Lennart Åhlen LP_PWI Preamplifier Specifications: •Switchable E-field / Density •100mW power consumption • 500kRad Radiation hardend • Positive feed back current generator •E-field: DC-300Hz +-100V input range DC to 3MHz small signal bandwidth Better than 10^12 input resistance 1nA – 100nA Current Bias range 16 nV/sqr(Hz) noise •Density: DC to 10kHz bandwidth 10pA to 100uA input current range +-100V Voltage Bias range New development: Find new low noise Rad hard operational amplifiers Develop a MEMS chip including nano-switches and amplifiers MEMS amplifier 10x10x1mm total mass 4x30g (4x250g) MEMS pre-amplifier implementation Conclusions •Each single requirement is hard to meet, and combined it is more or less impossible to build a component that meet all requirements (voltage, leakage current, temperature and size). •Lowest leakage current is reached with own-built reed-relay (fA or pA) •Smallest size is reached by MEMS-based switch, (~100 um) •pA leakage is easier to reach at lower voltage. •Reed relays: In test and measurement, particularly in integrated-circuit (IC) testers and wafer testers, with parallel high switch point counts, leakage current becomes a real problem. Reed relays designed to handle fast digital pulses will exhibit extremely low leakage currents in the order of 0.1 pA or less. No other technology currently offers anything close to this combination. •To manufacture reed switches 5mm or less in a stable manner is difficult. •Alternative system approach is to use 2 boxes; one with thick radiation shield for small and radiation sensitive components and one with less shielding, if reed relays are enough radiation tolerant. Alternative system approach. Radiation protected area for sensitive components, with thick Al capping (solid state relay) + Area for less sensitive components (low leakage reed relay) RA_PWI and RWI Preamplifier FET follower or FET input negative feed back amplifier ? •High distortion •Limited output range •Low power •Simple Specifications: 1kHz to 50MHz Bandwidth +-1V input range •Low distortion •Medium power •Complex 2 nV/sqr(Hz) noise 100mW power consumption Amplifier from Tohoku University 100Hz to 50MHz 0.6W RPWI EGSE Principle Block diagram ESA INTERNAL REVIEW RECOMMENDATIONS COMMENTS ON ELECTRONICS System: •We have to look into single point failure areas in the system design. •It looks like the magnetic requirements will govern the system grounding concept and we urgently have to find a way to prevent that to happen. Instrument: •ESA just reminds us of the pre- amplifier radiation environment, which we have under control. However, ESA needs to give the specifications how to test parts. •Mass and power impact on fall back options need to be estimated. •The thermal environment for the pre-amplifiers and the boom mechanisms need to be identified.