1. Solar Probe Plus FIELDS SCM FM2 Sensor iPSR SCM design and performances May 11th, 2017

2. Summary
FM design overview (As built)
Documentation
FM2 performances

3. SCM description & performances requirements
SCM is a search coil magnetometer (inductive type)
Within the framework of FIELDS instrument consortium, SCM will contribute to cover science objectives by measuring fluctuating magnetic fields
SCM required performances related to magnetic field measurements are given in the FIELDS L3 requirement document :
3 components in the 10Hz to 50kHz frequency range
Maximum B field intensity : up to 3000nT at 3.5kHz
Minimum sensitivity, better than 10-3nT/Hz-1/2 at 100Hz
10-4nT/Hz-1/2 at 3.5kHz (SCM target 10-5nT/Hz-1/2)
1 component in the 1kHz to 1MHz frequency range
Maximum B field intensity : up to 6nT at 100kHz
Minimum sensitivity, better than 10-4nT/Hz-1/2 at 10kHz
10-5nT/Hz-1/2 at 100kHz

4. SCM description Pigtail Mechanical structure (foot) in PEEK
Insulating bedplate
3 search coil antennas
Assembly at 90°

5. Antennas design and manufacturing
2 mono-band antennas and 1 double-band antenna
Electrostatic screen (around each antenna)
Ferrite core
LF coil turns
Counter feedback coil 29 turns
Done by Microspire
MF coil 360 turns
Counter feedback coil 3 turns
Done at LPC2E
Mutual reducer (ferrite)

6. Failure on FM1 : antennas rework
Rework of the antennas at LPC2E to correct the faulty wire on antennas (responsible of the failure on FM1):
Remove the counter feedback coil + kapton layer
Rewire the counter feedback coil
Wire passing holes reworked to avoid sharp edges
Add the other elements for the double band antenna
FM1 coiling
FM2 antennas after rework

7. Preamplifier design and manufacturing
Preamplifier manufactured by 3Dplus company (ESA PID)
6 levels of flexible circuits with EEE components
Tantalum layers (0.5mm) at the top and bottom of the module
DDD protection
MF channel
Power regulation
LF channel (x3)

8. Preamplifier qualification (LAT)
Burn-in test circuit
Preamplifier LAT completed ans successful

9. Harness manufacturing
Harness made with ESA/SCC cables:
2 UTP AWG30 : temperature probes
5 STP AWG30 : output and cal. signals
1 STP AWG28 : heater
1 STT AWG28 : power supply
Connector 26 pins HD sub + 90° back shell (ESA/SCC 3401) non magnetic
Harness manufactured by Latelec company
1 modification at LPC2E : Band-it collar at the root the backshell replaced by lacing ribbon (because of its DC field measured by MAG)
Cut at good length after test on the boom
Collar removed

10. Mechanical structure Harness tabs (titanium) Foot (PEEK)
Closing plates (PEEK)
Centering ring (PEEK)
Centering ring (PEEK)
EC2216 glue
Insulating bedplate (PEEK)
M8-M4 inserts
(titanium)
Antenna tube
(carbon fiber)
ring (PEEK)
ring (PEEK)

11. Mechanical structure
Not visible on the picture : Copper tube (1mm thickness) inside the foot around the preamplifier
Assembly processes
Gluing with EC2216
Carbon tubes on the foot
Closing plates on the foot
Centering ring on the foot
Titanium inserts on bedplate and foot
Vacuum potting with STYCAST 1090SI + catalyst 23LV
Antennas inside the tubes (X3)
Preamplifier inside the foot
Design tested in vibration (qualification levels) on ETU in 2015

12. Thermal elements Heater : 248Ω
Flexible heater manufactured by MINCO (ESCC ), double layer for magnetic compensation
Glued on the copper tube around the preamplifier
2 thermistors 10kΩ close to the preamplifier (ref. YSI44907)
Thermal control
Housekeeping
80mm
45mm
36mm

13. GSE Magnetic shielding 4-layers of mumetal Inner dimensions 40x40x40cm
3 axis Helmholtz coil (ø24cm)
3 gains: 1dBV/nT, 20dBV/nT, 300dBV/nT

14. SCM documentation Design and interfaces As built
3D preamplifier detailled specification
3DPA
Interface control document
SPP-SCM-AIT-SCM-RP-0363-LPC2E V2.1
Support structure drawing
SPP-SCM-TEC TD-0134-LPC2E V1.6
As built
Incoming inspections datapackage
SPP-SCM-AQP-CRL-DP-0331-LPC2E
FM preamplifier CSI report (review at 3Dplus)
SPP-SCM-AQP-CRL-MM-0323-LPC2E
LF coils Delivery Review (review at Microspire)
SO-DIR-RPW-SC-0150-LPC2E
Harness delivery datapackage (review at Latelec)
SPP-SCM-TEC DP-0290-LPC2E
Mechanical elements drawings bundle
SPP-SCM-TEC DW-0194-LPC2E
3D preamplifier EID-P
EIDP_ a

15. SCM documentation PA/QA documentation PA plan
SPP-SCM-AQP-PAP-PL-0038-LPC2E V1.2
DML
SPP-SCM-AQP-MPR-LI-0121-LPC2E V3.0
DPL
SPP-SCM-AQP-MPR-LI-0122-LPC2E V3.0
DCL
SPP-SCM-AQP-EEE-LI-0115-LPC2E V2.3
FMEA
SPP-SCM-AQP-RIS-TN-0120-LPC2E V2.1
Parts Stress Analysis
SPP-SCM-AQP TN-0192-LPC2E
NC FM1 antenna failure
SPP-SCM-AQP-NCR-NC-0339-LPC2E V1.1 a

16. SCM documentation
Assembly, Integration, Tests
SCM test plan and procedure
SPP-SCM-AIT-SCM-PR-0195-LPC2E
SCM vibration tests plan
SPP-SCM-AIT-SCM-SP-0307-LPC2E V1.5
SCM thermal vacuum qualification plan
SPP-SCM-AIT-SCM-SP-0316-LPC2E V1.3
GSE description and user manual
SPP-SCM-AIT-SCM-MA-0324-LPC2E
SCM mounting procedure
SPP-SCM-AIT-SCM-PR-0329-LPC2E
Packaging, Handling, Storage, Transportation process
SPP-SCM-AIT-SCM-PR-0334-LPC2E V1.2
SCM FM2 performance test report
SPP-SCM-AIT-SCM-RP-0358-LPC2E V1.1
Log book
SPP-SCM-AIT-SCM-TL-0362-LPC2E 10/05/2017
Vibration test report
SPP-SCM-AIT-SCM-RP-0363-LPC2E
Thermal vacuum test report
Contamination witness analysis report a
Writing of test reports is on going, expecting facility data (accelerometers …)
Upcoming : TVAC contamination witness analysis report

17. Performances & characteristics
FM weight
Power budget : the power consumption of SCM FM is 311.4mW (FM mW)
Elements
Mass
SCM with pigtail (with connector saver)
500.81g
Bedpalte
54.38g
6 fixing srews
7.17g
Total mass of SCM FM2 unit
562.33g
FM g
Voltage
Current
Power
+12V
13.04 mA mW
-12V
12.91 mA mW

18. SCM performances : frequency response
L4 requirements
L4 requirements

19. SCM performances : sensitivity
Sensitivity level : similar to ETU and FM1
meet L3 requirements
L4 requirements : frequency shift of the low level 2kHz  800Hz and higher level

20. SCM performances : input dynamic
Input dynamic : maximum B field measured by SCM (L4 req.)
LF channels : 3000nT not on the whole frequency range
MF channel : 6nT ok
Frequency range impacted
Worst case
LF1y
59Hz – 14kHz
2660nT at 349Hz
LF2z
58Hz – 12.5kHz
2667nT at 320Hz
LF3x
93Hz – 2992Hz
2708nT at 350Hz