MERMAG-M/MGFMERMAG-M/MGF

MGF-OS

MGF-IS

MAST-MGF

MAST-SC

PWI-SC

Credit : RISH, Kyoto Univ.

MGF Block DiagramMGF Block Diagram

1 Hz SynchronizationEFD

CharacteristicsCharacteristics

Digital resolution pT 4 20 bit digitization

Measurement range nT ±2048  

Data Rate & Volume

Resolution & Range

Sample Rate Hz 128 MGF-O

    64 MGF-I

Data rate to DPU kbps 7.7 MGF-O

    3.8 MGF-I

128

7.7

Telemetry Budget Telemetry Budget (updated)(updated)

High 6.5 KBPSMGF-O : 16 bits/component × 3 components × 128 HzMGF-I : 16 bits/component × 3 components × 8 Hzstatus: 64 bits × 0.125 Hz

Medium 420 BPSMGF-O : 16 bits/component × 3 components × 8 HzMGF-I : 16 bits/component × 3 components × 0.5 Hzstatus: 64 bits × 0.125 Hz

Low 20 BPSMGF-O : 16 bits/component × 3 components × 0.125 HzMGF-I : 16 bits/component × 3 components × 0.125 Hzstatus: 64 bits × 0.125 Hz

Checkout 11.6 KBPSMGF-O : 20 bits/component × 3 components × 128 HzMGF-I : 20 bits/component × 3 components × 64 Hzstatus: 64 bits × 1 Hz

128

15.4

MGF-I Recent Development &MGF-I Recent Development &Development plan in Apr. - Development plan in Apr. - Sep.Sep. Recent Development

Basic performance of BBM is confirmed to

be good.

20-bit ΔΣ A/D converter in BBM

Linearity error was found to be « 0.01%

and achieve the target.

Noise RMS was about 3 digits.

Development plan

For the test of amplifier having better

performance and feasibility test of the 128

Hz sampling, 2nd BBM is now

manufactured.

The sensor design will be fixed based on

the measurement of noise level and offset

in the wide temperature range from -160 to

200℃. INPUT

OU

TP

UT

1/128 secondsSynch. signal

1/64 seconds

1/256 seconds

Filtering coefficients and Filtering coefficients and frequency properties frequency properties of MGF-Iof MGF-I

frequency Hz

frequency Hz

frequency Hz

100 1000101

1 10 100 1000

1 10 100 1000

Phase delay

Time delay

Amplitude

Filter coefficients

MGF-O Heritage: VEXMAGMGF-O Heritage: VEXMAG

Heritage instruments – Venus Express VEXMAG

Launched on November 9, 2005.

On November 18 and 19, 2005 the commissioning of the

magnetometer (VEXMAG) as well as the boom deployment took place

successfully. Since then VEXMAG is operational with out any problems.

Venus Orbit Injection (VOI) is going to take place on April 11, 2006

followed by the near Venus commissioning of VEXMAG on April 22.

MGF-O Heritage: VEXMAG MGF-O Heritage: VEXMAG (cont.)(cont.)

Proof of instrument performance during boom deployment

Eigen frequency oscillation of the boom measured with a 100 pT peak-

to-peak field signal at 8 Hz (bottom right plot)

17:06:41.518.11.05

17:06:41.7518.11.05

17:06:4218.11.05

550

551

552

553

554

555

OS

-Z [n

T]

17:06:4318.11.05

17:06:4418.11.05

17:06:4518.11.05

114

114.5

115

OS

-Z [n

T]

17:06:4118.11.05

17:06:41.518.11.05

17:06:4218.11.05

17:06:42.518.11.05

17:06:4318.11.05

17:06:43.518.11.05

17:06:4418.11.05

17:06:44.518.11.05

17:06:4518.11.05

100

200

300

400

500

600

OS

-Z [n

T]

MGF-O Heritage: ThemisMGF-O Heritage: Themis

Heritage instruments – Themis FGM

Themis (launch: October 2006) flight models (five instruments) were

delivered and integrated to common DPU as well as boom.

Spacecraft 1 is presently being transported to JPL for environmental

tests.

Development Plan Mar.-June Development Plan Mar.-June 0606

MGF-O: IGEP (Germany)1. A set of ringcores, manufactured by exclusively high temperature

materials, has been produced and is currently under test.2. Upgrade of Magnestrode for calibration and test measurements up to

200 °C is ongoing.3. More detailed thermal modeling of the fluxgate sensor is ongoing.

IWF(Austria)1. The design study of a sigma-delta DAC for the possible use in the

digital magnetometer concept has been finished. It cannot be used due to a too high non-linearity: search for other options.

2. The effect of the periodic synchronization of the MGF-O data acquisition by the MGF-I 1Hz clock has been studied using a Matlab/Simulink simulation: effect is acceptable but nevertheless the simulations will be continued in order to further reduce it.

Status of Sensor Harness Status of Sensor Harness TestingTesting

Already performed tests: 1) Basic thermal analysis 2) Standard outgassing (@125 °C) 3) High temperature outgassing (@240 °C) Conclusion of 1-3: The Goretex (ePTFE) insulation and protection

wrap of the cable is mechanically stable up to 250 °C with no mass loss below this temperature. The thermo-optical properties are 0.05 (alphaS) and 0.79 (epsilonIR).

However the "harder" tests are coming in the near future. ESTEC is still waiting for other samples which will also take part in the UV/VUV test at elevated temperature. The test will probably start this week and will last for several weeks.

MERMAG-P / MAG DesignMERMAG-P / MAG Design

PowerSupply

Instrument Controller

Inboard Sensor

Electronics

OutboardSensor

Electronics

HeaterPower

InstrumentPower

SpaceWireInterface

SensorThermistors

OutboardSensor

InboardSensor

SensorHarness

SensorHarness

MA

G In

stru

men

t Ele

ctro

nics

Box

Prime hardware responsibilities: IGEP: Sensor and sensor electronics IWF: Instrument controller IC: Power supply and E-box

Sensor and near sensor electronics are going to be nearly identical to MGF-O design