themis mission cdr -ucb, june 14-18, 2004 search coil magnetometer (scm) mcdr alain roux,...

THEMIS Mission CDR -UCB, June 14-18, 2004

Search Coil Magnetometer (SCM)

MCDRAlain Roux, CETP-Velizy

Co-i: O.Le Contel

Technical Manager: B.de la Porte* =>C.Coillot

Lead Engineer: A.Bouabdellah

Technicians: D.Alison & S.Ruocco

*Till june 2004


Technical Manager: Bertrand de la Porte

•team management, general schedule

Lead engineer: Christophe Coillot

•SCM support: design, manufacturing:

•Sensors : design, manufacturing, tests,

•PA: electrical design, tests procedures, EM&FM tests.

•Sniffer design, manufact. & tests

Engineer: Abdel Bouabdellah

•ICD&PAIP management, Vibration tests,

•PA: PCB cabling, design of housing,

•manufacturing, PA I/F.

Technician: Dominique Alison

•PA/PCB design,

•Manufacturing sensors,

•I/F PA: design, manufact., tests

Technician: Sébastien Ruocco

•Sniffer & tests:

Technical Manager: Christophe Coillot

•team management, schedule.

•SCM support: manufacturing, schedule,

•Sensors : manufacturing, EM&FM tests,

•PA: tests procedures, EM&FM AIT

•Lead Engineer: Abdel Bouabdellah

•ICD&PAIP management, Vibration tests,

•PA: PCB cabling, manufacturing, PA I/F general schedule. Integrations.

Technician: Dominique Alison

•PA/PCB design,

•Manufacturing sensors,

•EM&FM tests&integrations

Technician: Sébastien Ruocco

•PA: FM tests.

•Sensors: FM tests.

•Integrations

Team re-organisation


IN.SCM-1. SCM shall provide a critical test for the role of waves at substorm onset, in various models (with EFI).

Compliance.

IN.SCM-2. SCM shall measure the 3D AC B-field from 1 Hz to 4kHz.

Compliance.

IN.SCM-3. The SCM sensitivity shall be better than 1pT/Hz^1/2 @10Hz , and 0.1 pT/Hz^1/2 @1 kHz.

Compliance. 0.7pT/sqHz@10Hz

0.04 pT/sqHz@1kHz

IN.SCM-5. The transfer function of the SCM sensors (amplitude &phase) shall be known with an accuracy better than 5%.

Compliance. Tests of EM will be made in Chambon la Forêt, end of June.

IN.SCM-6. On each spacecraft the 3 magnetic antennas, shall be held orthogonal by a structure procured by CETP

Compliance. Structure meets specs : mass, vibrations (modeling, and vibration tests)

Sensor requirements


Sensibility EM (pT/sqrt(Hz)

0.001

0.01

0.1

1

10

1 10 100 1000 10000Fréquency (Hz)


Design includes EPR remarks and numerical simulation results. Interface is completely defined (cf. P. Turin). EM structure delivered by GdTech to CETP: May 17th.

3-axis structure


PA Design by 3D+

Mechanical characteristicsMechanical characteristics: : • 2 amplification levels• 3 radiation shielding levelsDimensions: 20 x 20 x 15 (mm)Weight : 15 g

Pre-Amplifier module


PA Layout on PCB&box

a


Item Specification Status

Search Coil Size

Search Coil Mass

175x175x175 mm

600 g

176x176x176 mm

608 g (+/-8)

Most masses meas.

Pre-Amp Size

Pre-Amp Mass

Pre-Amp Power

80x70x40 mm

200 g

90 mW

109 x 94.9 x 30mm

200 g (measured)

86 mW (measured with EM)

Power &mass summary


Operations

• When ON, SCM is continuously measuring the magnetic field up to 4 kHz.

• Once per orbit a calibration is run for 30 secs (default)

• After 60 seconds, the Calibration is automatically turned off.


Test Matrix

Model I/F EM EM EM FM FM FM

Item PA SC PA SC+PA SC PA SC+PA

Electric. Verificat. X X X X X X X

Full Calibration X X

Mech. I/F,M, CoG, MoI X X X X

Vibrations Q Q A A

Thermal tests (cycles) Q Q A A

Thermal Vacuum Q.idpu A.idpu

Interface to IDPU X

Pre-integration UCB X X X X

Integration to S/C X X


Test plans : SC

After winding of internal tube

Verification of Impedance

Done (EM)

After potting of the magnetic core

Verif. of imped. Magnetic flux resp. (with PA

Done (EM)

Done (EM)

After overall potting Verif. of imped. Magnetic flux resp. (with PA

To be done end of june EM

After 3-axis assembly, and connect. to PA

Transf. funct. (SC in mu-metal box, metrology, vibr., temp. limit,

Full cal. in Chambon

Begin of july EM

After delivery to UCB Therm. Vac (with S/C)


Test plans: PA cubes

Single flex Electrical verification

Offset adjustment

Done (EM&FM)

Done(EM)

After cube assembly &potting

Electrical verification

Temperature test*

(-50° - +60°)

Done(EM&FM)

Done(EM)

* Takes into account changes suggested during CDR peer review


Test plans: full PA box

After PCB cabling Electrical verification Done

EM

After assembly in the housing

Electrical verification

Metrology

Vibrations

Full range temp. tests

Done

TB done

Done

Done

Connect. with SC Transfer funct.,SC in mu-metal box.

Full cal. in Chambon

End of June

After delivery to UCB Thermal vac. With IDPU


Bench test configuration


Mag. calibration: Chambon


Interface verification at UCB

An interface model has been built and sent to UCB to test I/F to IDPU .

• Same Power, Command, analog output interfaces

• Power and Cal Mode identification by LED

• Cal Signal re-injected to the input

• A signal generator can be connected to each input


Pre-integrations at UCB

• After delivery to UCB (Incoming Inspection, Bench Test)

•Sensor in the mu-metal box

•Electrical Integration

•Power ON and functionnal test

Validation can only be done by analysis of telemetry data

I&T at UCB


I&T at s/c level

Integration on the spacecraft

• Mechanical Integration of the PA, connection to the boom harness

• Sensor in the mu-metal box

• Electrical Integration (bounding, isolation)

• Power ON and functionnal test

Validation can only be done by analysis of telemetry data


SCM tests at s/c level: 1

Extended cable 1.5 m

Antenna in the mu-metal box

pre-ampInitial configuration:

The sensor is inside the mu-metal box, connected to the PA via the boom harness

Requirement: keep the sensor in the mu-metal box until all experiments are integrated in the spacecraft (mission operation test)


SCM tests at s/c level: 2

WHAT CAN BE DONE WITH THE SENSOR IN THE MU-METAL BOX?

• Verification of the labelling of axis (X,Y, Z)

• (Re)-verification of the end-to-end calibration

• Phase relation between the 3 components (for the waveforms)

• Measure the conducted noise

• SCM/EField timing reference [and inter-calibration]


SCM integr. at s/c level: 3

SENSOR MOUNTED ON THE BOOM

• PA saturated by the 50/60 Hz (except in an EMC chamber).

• No measurement possible but a major failure would be detectable.

INSTALLATION OF THE MLI: preferably at the last moment, before s/c vibration tests.


EMC tests at s/c level

• CETP can help analyse the AC radiated noise around the spacecraft.

• A « magnetic sniffer » has been built and delivered to UCB.

• In order to avoid the saturation by the 50/60 Hz, the analysis is separated into two bandwidths: below 50 Hz and above 300 Hz (5th harmonic).


SCM integr.; team support

• The SCM team will support all critical activities, for the integrations.

• However, due to the large number of satellites, a strategy should be implemented to limit the number of travels, cost and time spent

• Support EM integrations in any case

•The FM will be delivered 3 by 3 and the level of support for each test will be agreed upon with UCB

Capability of remote access/support should be implemented


SCM schedule- Key dates

EM delivery to UCB July 2004

EM pre-integrations at UCB

July 2004

3D cubes (FM) delivery to CETP

July 23th, 2004

FM1,2, and 3 availability: Sept. 24th, 2004

FM4,5, and 6 availability: Nov.10th, 2004


Status of questions/RFA’s

SCM-1

Ground

ing &

testing

Concern that grounding and shielding is not yet defined—need to make sure all documents are consistent. This was an action from the last review, but understand that this is common for CDR-level fields missions.

•Grounding review (end of may) UCB&CETP agreed upon:•Coils&shields of each SCA GND (not to CGND)•Thermal blanketCGND•Overall shielding of boom cable

by conductive tape. •Backshell of PA connector also shielded•No need to shield SCA connect.

SCM-2

Simult. Firing of actuat.

Ensure that both actuators are fired simultaneously, at temperature and voltage extremes during testing. (Slavin—based on Double Star dual boom deployment failure.)

The mag-booms are released simultaneously



SCM-3

Tests of 3D components beyond predicted levels

CETP should ask 3D to test components beyond the predict levels. Most electronic parts are tested at greater levels individually than at assembly level.

Done; new test procedures defined with UCB&3D; temperatures ranges extended by +/-5°

SCM-4

PCB mounted on 4 corners

PCB mounted on four corners. Is this adequate for limit loads for deflection [probably okay, ~4mm standoffs] and strength? Recommend calculation to ensure populated board does not exceed strength limits.

It is not typical to calculate the strength requirement of boards. Vibration test performed successfully.

SCM-5

Wires inside PA box

Wires from connectors to board are long. The wires should be laid out differently (increase board size, glue the longest wire on the PCB?)

Longest wires are now glued


SCM-6 details

SCM-6 (cnd.)

Summary of THM-SYS-005:

• SC(antennas) qualified by CETP (thermal cycling) without vacuum. TV test at s/c level.

• PA qualified in temperature (currently done) by CETP, without vac.. TV done at UCB, together with IDPU.



SCM-6

Thermal vac./thermal air cycling

UCB and CETP need to have an agreement on how many thermal vacuum or thermal air tests cycles are performed before delivery (by s/c CDR)

THM-SYS-005 calls out the required cycles & temperatures

SCM-7

Thermal levels

Thermal levels should come from document such as environmental requirements.

We are adding a reference to "THM-SYS-005 Instrument Payload Verification Plan and Environmental Test Specification" to the ICD

SCM-8

Test sequencing

Details of test sequencing, configuration (are sensors connected to pre-amps during testing)-Teams have begun to discuss; more meetings between the I&T lead, PM, SE and CETP would be beneficial.

Marc Kaylor (Swales) is drafting the basic probe flow, so that Rick Sterling can insert the details of the SCM tests.


SCM-9 Review EMI/EMC levels relative to FAST

Rick Schnurr volunteers to review EMI/EMC levels relative to FAST, and tell UCB which levels may present difficulties (noise in the chamber).

Data has been provided to Rick.

SCM-10 Populating boards in advance

Recommend populating boards in advance of 3D cube arrival, to help schedule

Agreed

SCM-11

Nickel plating of small objects far away from sensor

Would be beneficial in magnetics plan to note: don’t consider nickel plating small objects far away from sensor (such as nickel coating on 3D cubes).

Although not specifically called out in the magnetics plan, the use of nickel plating has been tested and tracked. The SCM Pre-Amp 3D Plus modules were tested in Braunshweig in Dec. and determined to have a magnetic moment well within the requirements for THEMIS.



SCM-12

Thermal treatments on e-box.

Thermal treatments on e-box is in need of definition.

The thermal treatments have now been defined by UCB. The top of the preamp will be anodized but the rest of the box can remain alodine.

SCM-13

Chambers used for EMI/EMC tests

The chambers used for EMI/EMC tests usually do not present a clean AC magnetic environment. This is why tests on subsystem with a search coil inside a large mu-metal chamber are important when a careful verification is needed. Such a facility exists in France at Chambon-la-Foret.

We believe this is a recommendation to do what we have planned. So the response is to keep going as planned.



• Ressources (mass & power) are compatible with allocation.

• Tight schedule, yet delivery dates for EM and FM are compatible with the schedule of the project.

• PA cubes (EM) meet requested performances. PA box passed temp. & vibr.tests ; no problem.

• Sensitivity meets specs

• Antenna structure (EM) delivered. Meets specs.

Summary

themis mission cdr -ucb, june 14-18, 2004 search coil magnetometer (scm) mcdr alain roux,...

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