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MUPUS Team Meeting. < MUPUS> Status. Graz, 24/25 Oct 2013. PEN inflight calibration 4. 14 inflight calibration points between -107°C and -91°C 3 PEN sensors (No 2,7,10) showed jump (< 0.5 K) in R-T characteristic after THC power calibration in PC#12
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MUPUS Team Meeting <MUPUS> Status Graz, 24/25 Oct 2013
PEN inflight calibration 4 • 14 inflight calibration points between -107°C and -91°C • 3 PEN sensors (No 2,7,10) showed jump (< 0.5 K) in R-T characteristic after THC power calibration in PC#12 • No changes between PC#12 and PC#13 => correction possible • No active heating before FSS !
MUPUS PEN Inflight Calibration 5 • R0(-100°C) and TCR(-100°C) from 16 inflight calibration points between -107°C and -91°C • Corresponds to TCR ~ 0.0022 when evaluated with standard T0=0°C
(prelimenary) PEN uncertainty budget 1-Sigma • Uncertainty(@T=-200°C, k=2) = 3.2 K • uncertainties of reference resistors R100, R20 • uncertainty of h/k-2 Pt-100 (Class B, incl. line resistance correction ~ 1K / 31/2) • Precision(@T=-200°C, k=2) = 2.6 K • Uncertainty due to linear extrapolation • Uncertainty due to neglection of quadratic term (2-3 10-7 K-2, FS measurement) • Uncertainty due to imperfect wire correction (assumed 20% of nominal Rw) • Uncertainty due to assumption of homogeneous PEN temperature (assumed 0.5 K / 31/2) • Uncertainty due to electronics nonlinearity (FS, 0.25 K / 31/2) • Uncertainty due to electronics noise (0.016 K, FM cruise checkouts)
TM inflight calibration 2 6-25 µ 13-15 µ TM sensors lost sensitivity (but stable during cruise)!
TM inflight calibration 4 6-25 µm 13-15 µm Extrapolation to TV test conditions: S/S0 ~ 0.72 (6-25 µm) S/S0 ~ 0.86 (13-15 µm)
Depth Sensor FM FS • DS values stable since 2006 (no data earlier) • Slight dependence on balcony temperature (similar for FS) • Precision (Repeatibility, FS) ~ 75 DU(~ 3.5 mm)
ANC-M (accelerometer) FM FS • ANC-M Offsets stable since PC#4 (Nov 2006) • Slight dependence on board (EBox) temperature ~ -1 mV/K • Noise stable at 0.6-0.7 mV
MUPUS FM Status Summary • All MUPUS hardware fully operational when entering hibernation • ComDPU working only at ½ nominal speed (known since 2006) • No indications for h/w changes during cruise with one exception: • 3 PENEL sensors showed jump in R0 (~0.5-1 K) after (very low power) THC heating • Calibration problems exist: • PENEL: extrapolation due to short baseline of inflight calibration points • TM: significant sensitivity loss already pre-launch
MUPUS RM Status • EQM DPU killed in Nov 2012 • Stupid handling error by the project manager ! • Replaced by last FM-series (reserve) DPU stored at DLR • RM functional • BUT: new PENEL-FS problem • Occured after insertion tests with SESAME at Philae GRM • Strange: everything ok during all functional tests including the last one before switch-off • No valid measurements anymore when red tag jointer connecting PENEL electrical to structural GND close • Everything ok when red tag jointer open !
MUPUS PEN Inflight Calibration 1 PENEL, T=-50°C • Inflight calibration needed to cover low T expected for the comet • Method: • Use Pt-100 in the holder as reference • Assume that PEN tube and holder at the same temperature in equilibrium (before PENEL switched on, justified by TV test with PEN FS) • Interpolate resistance backward in time to start of PENEL preheating (equilibrium) • => Ri=Ri(Tref), i=1,2,…,16 Pt-100 PEN1 PEN16 TCU-MUPUS-DD
MUPUS PEN Inflight Calibration 3Backward Extrapolation PENEL heat wave PENEL heat wave Nearly linear increase of R during first 30 min. Calibration (holder) Pt-100 • Backward extrapolation gives reasonable R(T) point ! (random) uncertainty estimate ~ 0.5 K (neglecting deviations from homogeneity assumption) + systematic uncertainty of Tholder ~ 0.8 K
MUPUS TM Calibration 1 Thermopile principle: T-differences between sensor and object => Uth TSens must be measured separately ! Object radiation Blackbody radiation Housing radiation