Swarm IRF-Uppsala ICR 2006-05-09

IRF Organisation/Management For Swarm: Manager: Jan-Erik Wahlund Technical lead: Lennart Åhlén Contract signature: Lars Eliasson

Open issues to interface requirements Boom units foot-print Harness accommodation LP mechanical drawings are still preliminary S/C electric environment Full analysis needed at ESTEC (A. Hilgers) Might effect CEFI/LP performance

IRF-U Activities in phase B2a (1) Meetings: B2a LP kick-off (20-22 Feb-2006, ComDev) ComDev PAQA inspection visit (15-17 March, IRFU) EADS Interface & accommodation (Apr-5, telecon) Weekly telecons with ComDev LP accommodation Suitable locations for the two LP sensor units have been identified S/C electric environment need be investigated

IRF-U Activities in phase B2a (2) Processor choice: Delivered flight S/W code for processor emulation testing Testing, fine tuning and fit testing of FPGA algorithms by use of Matlab and Xilinx II development board (ongoing) Fine tuning of analogue design (block diagram) to better fit scientific requirements (ongoing) ERC32 (25 MHz) is too slow LP needs 20 kHz interrupt processing LP need download 20 kHz data during commissioning Léon-2 (100 MHz) preferred Gives better margins from start of project SOC to ComDev requirements: IRFU has delivered compliance list DPA procedure need further negotiations

IRF-U Activities in phase B2a (3) Operation mode, E2ES, L1b processor, Performance Normal mode & Calibration operations definition are almost final Mode & Calibration doc:s delivered E2ES & L1b algorithms delivered E2ES codes are under development (matlab) L1b codes already exists (based on Cassini analysis) Performance analysis delivered Breadboarding EM model scope is settled No analogue bread boarding activities foreseen One analogue channel test board will be manufactured for SW and FPGA algorithms verification and testing. This board will also be used for EGSE tests. NOTE: This board is mainly developed and funded for by other projects

IRF-U Activities in phase B2a (4) Documentation Program management plan: IRF progress report shall include schedule and risk registry Risk management plan: IRF shall maintain and update a LP risk registry andspecial focus should be put on tracking and assigning due date to actions in that registry PA & QA plans: IRF shall provide a statement of compliance list for the PA/QA CEFI Swarm document PAR_ESA_50070_001 Rev P0 Phase B2b, C/D schedules To be delivered

CEFI LP Block Diagram: Last update 2006 04 25 Only a single 16bit DAC needed for AC and DC probe bias generation Relaxed science requirements on AC amplitude dynamic range Redundant external ADC 2.5V reference introduced Due to local alert in the Bepi C MMO community regarding stability of the internal ADC reference. In order to calibrate for ADC offsets four inputs will be added to the multiplexer. Due to low analogue phase drift, observed at SPICE simulations, the second calibration relay could be excluded. TBC by further simulations. These changes will not require any additional recourses.

Preliminary CEFI LP boom design.

LP Mechanical Accommodation

Preliminary CEFI LP GSE concept

LP preliminary active parts list

LP Normal mode Includes HM ZM SM-block: 2x128 points voltage sweeps (up/down) 2 Hz alternating HM/ZM-blocks 16 Hz part of orbit – CEFI support HM Amplitude ripple at 164.5 Hz P1 at +2 V & Uexp (on exponential electron part) P2 at -2 V ZM Track zero crossing of U-I characteristic (P1) Track USC (P2) I, dI/dU -2 V +2 V USC 1s 0.25 s P1 & P2 P1 P2

E2E Simulation chain Plasma model Probe theory LP H/W (incl. FPGA) Ne, Te, Vi, Ti, mi variations Probe theory Sheath model for e- Combined Ti/ram ions LP H/W (incl. FPGA) Analog: op amp noise ADC quantization Mixing (FPGA) Filtering (FPGA) Numerically controlled oscillator (NCO) LP flight S/W Algorithms in processor Analysis on ground Level 1B analysis

Level 1B algorithms LP Normal Mode: High time resolution data derived from continuous mode-blocks calibrated by probe bias sweeps (every 128 s) Calibration using onboard offset determinations Sweep analysis based on existing routines for Cassini RPWS LP data reduction (illustrated in flow chart)

LP performance analysis results (1) Voltage Sweeps (SM) & Harmonic mode blocks (HM) The required accuracies can be achieved over a wide range of plasma parameters Further optimization/operations of FPGA and processor and the use of more elaborate analysis codes will improve performance further

LP performance analysis results (2) Compliance with SW-RS-ESA-EF-003 R-EFI-11 The plasma density distribution of the ionosphere shall be determined with an accuracy better than 0.5*1010 m-3 RMS, for signals encompassing all scales from global to 10 km (full wavelength). Intend to comply. The Langmuir Probe can meet this goal, pending optimization of amplifier gain settings. R-EFI-12 The ion and electron temperature shall be determined with an accuracy better than 1% of the signal strength encompassing all scales from global to 200 km (full wavelength) for periods up to 3 months. Te accuracy will be ≈1% for Ne > 1010 m-3. For lower Ne better than 5%. R-EFI-43 The plasma density shall be measured in the range from 108 to 5*1013 m-3 Compliant.

LP performance analysis results (3) Cont. Compliance with SW-RS-ESA-EF-003 R-EFI-44 The measurement accuracy (2 sigma) of the plasma density shall be better than 1% in the range 108 to 2*1012 m-3. Intend to comply. See the comment R-EFI-11. R-EFI-45 The electron temperature shall be measured in the range from 0.1 eV to 10 eV to within 0.05 eV. Compliant for Te £ 0.3 eV; higher temperatures remain TBD. See IRFU- Swarm- ERRSIM. R-EFI-47 The EFI shall measure the difference of potential between the spacecraft and the plasma over a dynamic range greater than 2 V (TBC). Compliant.

Swedish Institute of Space Physics Uppsala (Ångström laboratory) Kiruna (Rymdcampus) Umeå (Skogshögskolan) Lund (IDEON) Swedish Institute of Space Physics

Space Plasma Physics, IRF, Uppsala Scientists: Mats André (Professor) Jan Bergman Stephan Buchert Anders Eriksson Jan-Erik Wahlund Post-Docs/Guest Scientists: 6-8 Students: 10-15 Engineers: Sven-Erik Jansson Harley Thomas Walter Puccio Lennart Åhlén Software engineers: Liza Dackborn Reine Gill Adminidtration/computer support: Anita Andréen-Rogelius Bertil Segerström Ingrid Wahlberg

P4 - Space Plasma Physics Cluster (2000-2009), E-field, PI, M. André Cluster EFW Cassini (1997/2004-2008), LP, Co- I, J.-E Wahlund Rosetta (2004-2014/15) 2xLP, PI, A. Eriksson Cassini RPWS + Groundbased EISCAT, Sweden/Norway/Finland EISCAT, 2xSvalbard Rosetta LAP