scm teamfields ipdr – scm design 1 solar probe plus fields instrument pdr search coil magnetometer...
Post on 02-Jan-2016
222 Views
Preview:
TRANSCRIPT
SCM team FIELDS iPDR – SCM design 1
Solar Probe Plus FIELDSInstrument PDR
Search Coil Magnetometer SCM
T. Dudok de Wit & G. Jannetand SCM team: C. Agrapart, P. Fergeau V. Krasnosselskikh,
P. Martin, M. Timofeeva-Bouaroua
LPC2E, CNRS and University of Orléans
Contact : ddwit@cnrs-orleans.fr
SCM team FIELDS iPDR – SCM design 2
Outline
• SCM instrument general description, specifications & performances
• SCM instrument design– Antenna design– Preamplifier design– Electrical interfaces– Mechanical design and interfaces– Thermal design and interfaces– Calibration– Heritage
• Conclusion and main issues
SCM team FIELDS iPDR – SCM design 3
Instrument general description
SCM is a search coil magnetometer (inductive type), consisting of:•2 single-band antennas (10 Hz-50 kHz range)•1 double-band antenna (10 Hz-50 kHz & 1 kHz-1 MHz)•4-channel miniaturized preamplifier inside sensor foot•sensor foot
Analogue outputs are processed by 3 modules from FIELDS-MEP•DFB will routinely compute spectral matrices and on demand capture waveforms from the 3 LF channels•RFS will compute spectra from the MF channel•TDS will capture waveforms from the MF channel
3 search coil antennas
3D preamplifier
SCM team FIELDS iPDR – SCM design 4
Level 3 Requirements
• Measure AC magnetic fields from 9.5 RS to +0.25 AU• 3D magnetic field (LF coil, 10 Hz - 50 kHz)
– Min. sensitivity 10-4nT/Hz-1/2 at 3.5kHz ; Max. field intensity 1000nT at 3.5kHz
• 1D magnetic field (MF coil, 1 kHz - 1 MHz)– Min. sensitivity 3.10-5nT/Hz-1/2 at 100kHz ; Max. field intensity 6nT at 100kHz
LF
MF
SCM team FIELDS iPDR – SCM design 5
Performance expectations
3.16mV/nT
2.51mV/nT
1.78mV/nT
0.09mV/nT
0.35V/nT
1.3V/nT
0.28V/nT
LF frequency bandwidth specification
MF frequency bandwidth specification
SCM frequency response measured with preamplifier and antennas prototype (3000nT @ 3kHz, 6nT @ 100 kHz)
SCM team FIELDS iPDR – SCM design 7
SCM design : Antennas
• Magnetic core consists of 3C95 ferrite: selected for its stable magnetic permeability (µr) at low temperatures
• Coils are performed with the following characteristics :
• Each antenna is inserted inside a carbon fiber tube filled under vacuum with STYCAST resin
• Finished antenna dimensions: ∅20mm length 104mm
100mm
Metallized epoxy flanges for the link
between coiling wire and harness
SCM antennas (TARANIS EM)
MF coil
LF coil
Ferrite mutual reducer
FunctionLF antennas
B1, B2, B3
MF antenna B4 in addition to B3
antennaPrimary coil 13 500 turns 360 turns
Secondary coil 32 turns 3 turnsWire ∅Cu 80µm ∅Cu 90µm
Ferrite coreLength: 100mm
∅coil: 5mm∅max (tips): 14mm
Length: 60mm∅inner: 12mm∅outer: 14mm
SCM team FIELDS iPDR – SCM design 8
SCM design : Preamplifier
• FM preamplifier– Built in 3D technology and manufactured by 3Dplus (compliant with space-
qualified PID reference 3300-0546 rev 7)– 5 stages of electronic circuits + Pin grid array on top (connection to
antennas) and bottom (power supply, signals)– Protection against radiation with 0.5mm of tantalum layers at each tip of
the module and a cylinder around the module– DDD protection implemented inside the preamplifier module (RC structure)
Preamplifier FM example (heritage
TARANIS)SCM preamplifier prototype
Dimensions•Height 32.3mm + 2x5mm for in/out pins•Inside a ∅18.7mm cylinder (PCB with octagonal section, width 16mm)
MF
channel
Power supply regulation
3LF
channels
SCM team FIELDS iPDR – SCM design 9
Electrical interfaces
SCM is connected to
– DFB, TDS and RFS for signal digitization and processing
– LNPS for ±12V power supply & heating
SCM team FIELDS iPDR – SCM design 10
SCM design : Electrical interfaces
• SCM harness definition– 1 shielded and twisted triple (for ±12V) & 9
shielded and twisted pairs – Cables from ESA/SCC 3901 019 series.
Temperature range -200°C to +200°C – AWG28 wires for power supply and heaters,
AWG30 for the others (flexible & reduced thermally conductive section)
• SCM connector – HD-sub 26pins, shell size A
• SCM harness accommodation: 30 cm pigtail – 20 cm = 1 turn around the foot inside the
MLI cavity – outside MLI cavity for connection to boom
harnessSCM HD-sub 26 pin connector
10 cm pigtail
Cables•4 for LF (X, Y, Z) and MF (X) signals•1 for calibration•1 for heating power •2 for temperature probe dedicated to heating control •1 for HK temperature probe (sent to telemetry)
SCM team FIELDS iPDR – SCM design 11
SCM design : Mechanical structure
• Mechanical structure inherited from Solar Orbiter design
• SCM mechanical assembly– Orthogonal assembly of 3 antennas (±0.1°)– Preamplifier inside the foot cavity, filled under vacuum with
STYCAST resin– Total mass with MLI 680g
Element individual mass
Double band antenna 72g
Mono band antenna (each)
59g
Closing plates (each) 3g
Centering ring 3g
Anti-rotation pin <1g
Radiation shield 18g
Sensor foot122
g
Insulating bedplate 39g
Preamplifier 25g
SCM team FIELDS iPDR – SCM design 12
• SCM mechanical interface with the boom– The insulating bedplate must be fixed to the boom before the rest of the instrument
N°
Function Element MaterialQty
LocationDimension
(mm) and tolerance
1 Fixing bedplate boom CHC Screw Titanium TA6V4 6 On 38 at 60° M4
2 Centering, Anti-shearing Bedplate pins PEEK 2 Centered on ZURF 10 g6
3 Foolproofing, Anti-rotation Pin Titanium TA6V4 1 On 38 pointing towards YURF 4mm g6
1
2
3
Bottom view Top view
SCM design: mechanical structure
SCM team FIELDS iPDR – SCM design 13
Mechanical design verification
• Current design analysis with Solar Orbiter specifications (simulated with FEM):– First vibration mode: 288Hz– Sinus vibrations: current design can bear
25g sinus with good margins– Random vibrations: Instrument
capabilities already validated up to 1.5g²/Hz
– Shocks: validated up to 2000g
• SCM FEM is ready – analysis shall be performed with
specifications for I-boom units
Mode 1 foot bending (along X axis)
SCM team FIELDS iPDR – SCM design 14
Thermal interfaces
• SCM environment– I-boom: -175°C as a worst case (TBD with EDTRD update)– No solar flux during Sun-pointing phases– Suitable thermal interface is required including insulation and heating
• SCM temperature ranges
element Operating switch-onnon-
operatingsurvival mode
Antennas-100 to +100
°C-100 to +100
°C-100 to +100
°C-100 to +100
°C
Electronics -50 to +80 °C -50 to +80 °C-60 to +100
°C-60 to +100
°C
Harness-200 to +200
°C-200 to +200
°C-200 to +200
°C-200 to +200
°C
SCM team FIELDS iPDR – SCM design 15
SCM design : Thermal interfaces
• Passive thermal control– direct heritage from Solar Orbiter design– protection against radiative losses:
double 15-layer MLI envelope– protection against conductive losses:
insulating bedplate reducing contact surface & decoupling instrument from fixing screws
– conduction through harness reduced by a full turn around the bedplate and increased pigtail length
Contact areafoot / insulating plate: 504mm²
MLI and harness accommodation
SCM team FIELDS iPDR – SCM design 16
SCM design : Thermal interfaces
• Active thermal control– Critical element is preamplifier– Heaters are wrapped around the
preamplifier (Flexible polyimide thermofoil by MINCO, space qualified ESCC 4009 003), powered by LNPS
– Temperature probe for heating control (Lakeshore PT-103)
– 1 HK temperature probe for transmission to telemetry (Lakeshore PT-103 likely)
• Required heating power– Thermal analysis in progress (software
compatibility problems)
heater
T probecontrol T probe
monitoring
SCM team FIELDS iPDR – SCM design 17
SCM design : Accommodation
• Location on I-boom is dictated by EMC requirements– Minimum distance from spacecraft : 3m is acceptable for science if RE-01
requirements are applied on spacecraft bus– Minimum distance from MAG unit : 1m is acceptable (interference tests,
June 2012)
Envelope of MAG drive frequency & harmonics
SCM-MF noise floor with MAG at 1m
SCM team FIELDS iPDR – SCM design 18
Summary of resources
• Power budget – Instrument power supply: 270 mW ±12V– Heating power: TBC (600mW allocated)
• Mass budget – total mass of SCM unit 680g– Instrument: 525g– Harness pigtail: 30g– MLI blanket: 125g– Harness: 55.2 g/m + 15 g/connector
• Overall volume with MLI blanket– diameter ∅110mm – height 165mm
Overall volume with MLI blanket110
16
5
85
∅77
SCM team FIELDS iPDR – SCM design 19
Calibration
• Pre-flight calibration– Frequency response measurement to
have SCM gain in V/nT– Sensitivity measurement to
demonstrate capacity of measuring small fields.
• SCM test bench is composed of :– Network/spectrum analyzer – Mumetal shielding to get a
magneticallly clean environment– Helmholtz coil system for magnetic
field generation
• In-flight performance testing– Onboard verification system– Sensor response to a calibration signal
(sine waves) sent by DFB– Exact CAL signal still TBD
SCM frequency response test bench (mu-metal box)
Flux feedback
Main coil
preamplifier
Measmt. signal
CAL signal from DFB
4 layers of µmetal20cm
Helmholtz coils
SCM team FIELDS iPDR – SCM design 20
SCM maturity: heritage
• Strong heritage from TARANIS & Solar Orbiter SCM
• TARANIS heritage – Antenna design: double band concept– 3D Preamplifier design and qualification
philosophy– Full instrument concept with preamplifier inside
the foot has been validated on a fully operational EM
– Assembly process
• Solar Orbiter heritage– Antenna ferrite core and coiling process– Mechanical interface– Thermal interface: conductive and radiative
insulations, heating system implementation
TARANIS EM search coil
SCM team FIELDS iPDR – SCM design 21
Conclusions and open issues
• SCM meets Level 3 requirements
• SCM has good level of maturity thanks to strong heritage from SCM on TARANIS and Solar Orbiter
• Open issues (peer review)
– EMC requirements impose minimum distance from S/C (RE-01 specification) and from MAG magnetometer. Final orientation of the antennas will be set accordingly.
– Thermal model definition and simulation to be done with Solar Probe temperature conditions. Heating power to be set accordingly.
– Mechanical and structural analysis to be updated with I-boom specifications to confirm the design
SCM team FIELDS iPDR – SCM design 23
• SCM sensitivity curves measured with preamplifier and antennas prototype
Performances expectations
10-3nT/Hz-1/2
10-4nT/Hz-1/2
10-5nT/Hz-1/2
L3 specifications
SCM team FIELDS iPDR – SCM design 24
SCM design: antennas
• Antenna internal structure– Dimensions: cylinder ∅20mm, length 104mm– Inner volume is filled under vacuum with STYCAST resin (epoxy)
Ferrite core
Finished antenna with wires and electrostatic shield
MF coilCopper foil separation screen
Internal potting with STYCAST resin
Carbon fiber tube
Harness: 2 twisted and shielded triple
LF coil
Ferrite mutual reducer
SCM team FIELDS iPDR – SCM design 25
SCM design : Preamplifier
• Radiation protection– Ta layers (0.5mm) at each tip inside the module– Ta cylinder (thickness 0.5mm) around the module
• EEE components status – All passive parts are space qualified (MIL-PRF or ESCC)– Active parts
• 2 space qualified: 1 OpAmp, 1 current diode• 5 Commercial parts: heritage from TARANIS and/or Solar Orbiter
– Commercial parts selected for performance and dimensions
• 3D preamplifier qualification– Manufactured by 3Dplus (compliant with space-qualified PID
reference 3300-0546 rev 7)– FM manufacturing lot to be submitted to Lot Acceptance Tests
(LAT), by heritage it will be based on:• burn-in (168h) and life test (1000h at 125°C) on 2 modules and DPA on
1 module• Fast temperature variations (500 cycles -55°C/+125°C) on 2 modules
and DPA on 1 module
– LAT will be adapted to Solar Probe mission
SCM team FIELDS iPDR – SCM design 26
DDD protection
• Injection of DDD at preamplifier output: waveform generated by the model proposed by APL• Implemented design: RC filter, a 4.7nF capacitance is added to the current electrical scheme• Working with 150Ω resistor already present
SCM preamplifier output stage
~5.5V at preamplifier output with 150Ω, 4.7nF config.
in
out
3 pF1500 ohms900 V
SCM team FIELDS iPDR – SCM design 27
DDD protection
• Component selection– 4.7nV capacitor in 1812 package, ESCC 3009 034
admissible DC voltage 1000V, dielectric strength 200% ⇒ 2000V pulse acceptable– Resistor: 2 components in 1206 package added to take margin
• Routing with SCM preamplifier PCB dimensions• Implementation is feasible on a single additional preamplifier stage
Protection structure x7
routing:
3 ½ structures on top and 3 ½ at bottom
Top view of protection routing
16mm
SCM team FIELDS iPDR – SCM design 28
• SCM mechanical interface with the boom: 2nd step– The instrument is fixed to the bed plate
N° Function Element Material Qty LocationDimension (mm) and
tolerance
4 Fixing foot to bedplate CHC Screw Titatium TA6V4 6 On ∅40 at 60° M4
5 Centering, Anti-shearing Ring PEEK 1 Centered on ZURF ∅10 H7
6 Foolprofing, Anti-rotation key Titatium TA6V4 1 On ∅50 pointing towards XURF Width 4mm g6
4
5
6
Top view
SCM design: mechanical structure
SCM team FIELDS iPDR – SCM design 29
• Additional shielding braid option– SCM harness is composed of 10 cables, if an overshield is implemented, required internal
diameter braid is ∅8mm. – AXON reference gives a mass of 52g/m
• Electronic protection option – Using resistor + capacitors to ground to protect the 4 measurement channels and power
supply regulation circuit– Can be implemented on an additional stage inside the 3D preamplifier– This circuit does not protect temperature probes
• 2 possibilities still in balance – Easiest solution is the additional shielding on harness with the drawback of extra mass and
stiffness– Electronic protection is the best possibility in terms of mass. A way of protecting temperature
probes shall be found
Harness DDD protection
SCM team FIELDS iPDR – SCM design 30
SCM design : EMC test results
• MAG-SCM interference test result– Decrease of MAG drive frequency spike with the separation
Measurements of June 2012
SCM team FIELDS iPDR – SCM design 31
• Frequency response measurement– Measurement for each channel (3LF and 1 MF) with a Helmholtz coil system and a
test bench– Inside a mumetal shield to avoid EMC disturbances– Outside in “free field” to verify “wall effects”– Gives SCM calibration curve (gain in V/nT and phase) used for production of data
in physical unit
Network analyzer
CH1
CH2
source Input signal to Helmholtz coil
µmetal shielding boxes
Gain control nT/V
Power supply
SCM harness
Gain control
4 layers of µmetal20cm Helmholtz
coils
SCM verification: calibration
SCM team FIELDS iPDR – SCM design 32
• Sensitivity measurement– Measurement for each channel (3LF and 1 MF) with the sensor alone in a mumetal
shielding box– Verifies the lowest signals SCM can measure
Spectrum analyzer
CH1
µmetal shielding boxes
Power supply
SCM harness
SCM verification: calibration
SCM team FIELDS iPDR – SCM design 33
SCM verification : in flight test
• In flight performance verification– Onboard verification system– Sensor response to a signal composed of sinus waves – Signal send by DFB during 4s (TBC)– Verify the correct behavior of the instrument (gain and phase) by comparison with ground
measurements
• This system can be used as a functional test on ground• Science measurements can be performed at the same time• Duration of CAL sequences and CAL frequencies
Flux feedback
Main coil
preamplifierMeasurement signal
Calibration signal from DFB
SCM team FIELDS iPDR – SCM design 34
SCM design maturity
• Antennas – Design is fully defined – Coils for ETU model have been received (coiling operation done by
Microspire)– MF coils for the double band antenna will be added at LPC2E
• Preamplifier– Electrical scheme is ready – Issue on DDD protection (additional circuit in the module for
protection) shall be fixed before starting activities with the manufacturer 3Dplus
Ferrite core and coils for SCM ETU antennas
SCM team FIELDS iPDR – SCM design 35
SCM Design maturity
• Mechanical design and assembly– Mechanical structure & machining process (tools and accessories)
are defined– Design shall be confirmed by analysis with I-boom mechanical
specifications– Assembly process is mastered (TARANIS
heritage), necessary tools (vacuum potting, glueing, alignment... ) already exist
• Thermal design– Thermal analysis is ongoing to deliver SCM thermal model and
defined required heating power (SCM urgent issue)– Heaters definition and implementation process are currently being
done (iteration with the manufacturer Minco). Heating power value is needed to finalize the design
SCM mechanical elements kit
SCM team FIELDS iPDR – SCM design 37
SCM PA/QA
• Package of Product Assurance documents available for PDR:
Document Reference
Product tree, issue 1.0, 03/20/2011 SPP‐SCM‐MNG‐GEN‐PT‐0002‐LPC2E
Product assurance plan, issue 1.0, 11/14/2011
SPP‐SCM‐AQP‐PAP‐PL‐0038‐LPC2E
PAP compliance matrix, issue 1.0, 04/13/2012 SPP‐SCM‐AQP‐PAP‐MT‐0082‐LPC2E
Declared components list, issue 1.0, 06/25/2013
SPP‐SCM‐AQP‐EEE‐LI‐0115‐LPC2E
Declared materials list, issue 1.0, 03/26/2013 SPP‐SCM‐AQP‐MPR‐LI‐0121‐LPC2E
Declared process list, issue 1.0, 03/26/2013 SPP‐SCM‐AQP‐MPR‐LI‐0122‐LPC2E
Failure mode effect analysis, issue 1.0, 04/26/2013
SPP‐SCM‐AQP‐RIS‐TN‐0120‐LPC2E
Documentation management plan, issue 1.0, 04/08/2011
SPP‐SCM‐MNG‐GEN‐PL‐0001‐LPC2E
SCM team FIELDS iPDR – SCM design 38
SCM PA/QA
Product assurance plan update
PAP compliance matrix update
Risks list update
• Work in progress:
• Future work:
top related