MERMAG-M/MGF MGF-OS MGF-IS MAST-MGF MAST-SC PWI-SC Credit : RISH, Kyoto Univ.

MGF Block Diagram 1 Hz Synchronization EFD

Characteristics Digital resolutionpT420 bit digitization Measurement rangenT±2048 Data Rate & Volume Resolution & Range Sample RateHz128MGF-O 64MGF-I Data rate to DPUkbps7.7MGF-O 3.8MGF-I

Telemetry Budget (updated) High 6.5 KBPS MGF-O :16 bits/component × 3 components × 128 Hz MGF-I :16 bits/component × 3 components × 8 Hz status:64 bits × Hz Medium 420 BPS MGF-O :16 bits/component × 3 components × 8 Hz MGF-I :16 bits/component × 3 components × 0.5 Hz status:64 bits × Hz Low 20 BPS MGF-O :16 bits/component × 3 components × Hz MGF-I :16 bits/component × 3 components × Hz status:64 bits × Hz Checkout11.6 KBPS MGF-O :20 bits/component × 3 components × 128 Hz MGF-I :20 bits/component × 3 components × 64 Hz status:64 bits × 1 Hz

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

1/128 seconds Synch. signal 1/64 seconds 1/256 seconds Filtering coefficients and frequency properties of MGF-I frequency Hz Phase delay Time delay Amplitude Filter coefficients

MGF-O Heritage: VEXMAG  Heritage instruments – Venus Express VEXMAG  Launched on November 9,  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 (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)

MGF-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.

MGF-OS Performance (1) Long Term Stability: < 1 nT over 100 days Offset vs. Sensor Temp.: < 2 nT/170 °C Equator-S Themis FS6

MGF-OS Performance (2) Noise vs. Sensor Temperature Venus Express

MGF-OS Performance (3) Offset Drift vs. Sensor Temp.: < 2 nT/170 °C (-70 … +90°C) Venus Express Outboard Venus Express Inboard

Development Plan Mar.-June 06 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 Testing Already performed tests:  1) Basic thermal analysis  2) Standard outgassing °C)  3) High temperature outgassing °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 Design 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