FGM-1 MPDR, 2/12/2015

FLUXGATE MAGNETOMETER

Fluxgate Magnetometer (FGM)

Kathryn Rowe

FGM-2 MPDR, 2/12/2015

TEAM ORGANIZATION

FGM-3 MPDR, 2/12/2015

Instrument Overview Instrument Description Development Overview

AGENDA

FGM-4 MPDR, 2/12/2015

INSTRUMENT OVERVIEW

4

ELFINFluxgate Magnetometer (FGM)Mission PDR Meeting

FGM-5 MPDR, 2/12/2015

EXPLODED VIEW

FGM-6 MPDR, 2/12/2015

Magnetic sectoring information for the EPD Potential to detect EMIC waves

WHY DOES ELFIN NEED AMAGNETOMETER?

FGM-7 MPDR, 2/12/2015

1. FGM Electronics

2. FGM Sensor/Cable

WHAT DOES THE FGM CONSISTOF?

FGM-8 MPDR, 2/12/2015

BLOCK DIAGRAM

FGM-9 MPDR, 2/12/2015

RFAS FROM PDR

1

FGM Resolution Requirement -- Waiting Board ApprovalThe FGM Resolution of 10pT was presented as a requirement whereas the noise level is 0.5nT/sqrt(Hz). The PRM may generate data with

FGM-10 MPDR, 2/12/2015

INSTRUMENT DESCRIPTION

ELFINFluxgate Magnetometer (FGM)Mission PDR Meeting

FGM-11 MPDR, 2/12/2015

Fluxgate Magnetometer‐ 3 Axis data stream‐ 24 bit, 6pT resolution‐ Dynamic Range: ±55,000nT‐ Noise: 0.4nT/√Hz @ 1Hz‐ Sample rate: 200Hz

Instrument DescriptionMagnetometer Electronics

FGM-12 MPDR, 2/12/2015

POWER REQUIREMENT - FGM

REQ ID Requirement Parent(s) Verification Method Verification Procedure

PLD‐35

The Payload subsystem shall not exceed the power allocated in the ELFIN system power budget

SYS‐22

T/A: Measured power consumption data during component tests;  Analysis of the complete set of Instrument states.

Power BudgetPowerBudget‐##‐B.xlsx

Power allocated for FGM: 0.5 W (during science data collection)Current best estimate:  0.423 WMargin: 15 % (0.063 W)CBE + Margin: 0.486 WContingency: ~0.014 W

Supply voltages: Currents:+8 V+3.3 V+1.5 V

30 mA35 mA45 mA

Power:0.24 W0.1155 W0.0675 W

0.423 W+

FGM-13 MPDR, 2/12/2015

PWA mounts to 4 Delrin® brackets with 2-56 socket head brass bolts at each corner

ELECTRONICSMECHANICAL INTERFACE

The Delrin® brackets connect to cubesat chassis with #4-40 countersunk brass screws, and the PWA lies perpendicular to the instrument stack

FGM-14 MPDR, 2/12/2015

INSTRUMENT DESCRIPTIONMAGNETOMETER SENSOR

3 Axis Fluxgate 48mm x 48mm x 25mm 58 grams without cable 106 grams with 1 m cable

FGM-15 MPDR, 2/12/2015

1. Conductor – 3 Twisted Pairs Material: Silver-Coated

Strength Alloy Thickness of Silver Coating:

2um min Size: AWG 28

2. Binder Material: Gore-Tex®

3. Severed Wire Shield Material: Solver-Coated,

oxygen free Cu Thickness of silver coating:

2.5um min4. Shcatch

Material: Gore-Tex®

FGM CABLE

Characteristics:Operating Voltage: 100VrmsOperating Temp Range: -150C to 200C

FGM-16 MPDR, 2/12/2015

Stacer is 75cm long Sensor connects to

stacer with #4-40 non-magnetic screws

Final harness length TBD. CBE is 100cm

MLI installed over sensor

SENSOR MECHANICAL INTERFACE

FGM-17 MPDR, 2/12/2015

STACER Keleva Design Inc A 75cm BeCu stacer boom with a

SMAR actuator and a flywheel break

FGM-18 MPDR, 2/12/2015

MASS REQUIREMENT - FGMREQ ID Requirement Parent(s) Verification Verification Document

PLD‐34 The Payload subsystem shall not exceed the mass allocated by Systems SYS‐14

System mass documented and tracked through assembly, integration and test

Mass BudgetMassBudget‐##‐E.xlsx

Mass allocated for FGM: 237 gCurrent best estimate (CBE): 199 gMargin: 15 % (29.9 g)CBE + Margin: 228.9 gContingency: 8.1 g

FGMComponent Maturity Qty Unit mass CBE Margin CBE+Margin

FGE (FGM Electronics) P 1 90.00 90.0 15% 103.5FGS (FGM Sensor with 1m cable) P 1 109.00 109.0 15% 125.4

FGM-19 MPDR, 2/12/2015

DEVELOPMENT OVERVIEW

ELFINFluxgate Magnetometer (FGM)PDR Meeting

FGM-20 MPDR, 2/12/2015

FGM REQUIREMENTS

REQ ID Requirement Parent(s) Comply?

FGM

PLD‐21 The FGM shall have a range of 55,000 nT SCI‐01, SCI‐04, SCI‐05Yes.  Current dynamic range is ±58,400nT

PLD‐22 The FGM shall have a resolution of 0.1nT SCI‐01, SCI‐04, SCI‐05 Yes. Current resolution is 7pT.

PLD‐23 The FGM shall have an absolute stability of 100 nT SCI‐01, SCI‐04, SCI‐05 Need to test

PLD‐24 The FGM shall have a relative stability of 1 nT/2 hr SCI‐01, SCI‐04, SCI‐05 Need to test

PLD‐25 The FGM shall have a noise level of 0.5 nT/sqrt(Hz) SCI‐01, SCI‐04, SCI‐05Yes. Current resolution is 0.4nT/sqrt(Hz)

PLD‐27 The FGM shall have a digitization of > 20 bits SCI‐01, SCI‐04, SCI‐05Yes. Current digitization is 24 bits

PLD‐28 The orthogonality of the FGM sensor shall be known to 

FGM-21 MPDR, 2/12/2015

Prototype Complete (Board and Sensor)

CURRENT STATUS OF INSTRUMENT

FGM-22 MPDR, 2/12/2015

Elfin Status (2/26/12) PRM with ST5 Sensor Feedback Resistor: 2.7K to 3.3K

Problems: Frequency Response Incorrect: LabView needs to be

updated Need New Drive Circuit

X axis Offset: 1867nT Dynamic Range: +/-64,000nT Noise Level: 402pT at 1Hz

Y axis Offset: -49nT Dynamic Range: +/-64,000nT Noise Level: 379nT at 1Hz

Z axis Offset: 3129nT Dynamic Range: +/-58,400nT Noise Level: 373pT at 1Hz

Power Consumption 3.3V: 32mA 1.5V: 42mA 8V: 28mA

TEST DATA

FGM-23 MPDR, 2/12/2015

STABILITY TESTING(2 HOURS)

FGM-24 MPDR, 2/12/2015

FGM IMPLEMENTATION PLAN

FGM-25 MPDR, 2/12/2015

1. Reduce dynamic range on X and Y axis From ±64,000nT to ±55,000nT Feedback resistors needs to be changed Increases margin on noise level

HARDWARE CHANGES NEEDED ONPROTO

FGM-26 MPDR, 2/12/2015

1. Change input clock from 32MHz to 16.384MHz GSE oscillator needs change

2. Change sample rate from 122Hz to 200Hz Need to implement anti-aliasing filter IDPU to average down to 10Hz

3. Change FPGA code from Libero Schematics to Verilog

FPGA CHANGES NEEDED ONPROTO

FGM-27 MPDR, 2/12/2015

1. Electronics Thermal Cycling (Expected temperature range needed) Need test plan Need to determine electronics temperature

dependence2. Sensor Temperature Cycling (Expected

temperature range needed) Need test plan Need to determine sensor temperature

dependence3. Alignment Test Need orthogonality of sensor

PROTOTYPE TESTING

FGM-28 MPDR, 2/12/2015

1. Minor board outline change Need to accommodate S/C harnessing

2. Remove JTAG connections on IDPU connector Lose ability to program in-flight (low risk)

3. Change connector from 26pin to 20pin Smaller connector to increase board space

4. Add ±15V supplies to IDPU connector WCA revealed supply rails for analog switch was

undervoltage5. Bring the drive circuit outside PRM Unable to change supply rails for analog switch

inside PRM

CHANGES FROM PROTO → EM