Thermal Balance Test of Solar Orbiter EUI Instrument Structural and Thermal Model with 13 Solar Constants

(1)

Thermal balance test of Solar Orbiter EUI

instrument Structural and Thermal Model

with 13 Solar constants

L. Jacques, J.-P. Halain, L. Rossi, M.-L. Hellin, P. Jamotton, S. Liebecq, A. Mazzoli, E. Renotte, P. Rochus

(2)

Outline

What we do at CSL? Solar Orbiter

EUI

Test setup presentation Test results

Test correlation Conclusions

(3)

Outline

What we do at CSL?

Solar Orbiter EUI

(4)

Space Center in Liège, Belgium

University of Liège Research Center (since 1959) Test facility for ESA:

– Class 10000 & class 100 cleanrooms

– 5 Vacuum chambers with optical bench (1.5 to

6.5m Ø)

– 2 shakers in cleanroom (also cryo-vib)

– Planck S/C, Herschel mirror, GAIA (PLM), XMM

(5)

Space instruments developed at CSL

EIT (SOHO), OM (XMM), FUV/SI (IMAGE), Sun baffle (CoRoT), HI

(STEREO), PACS grating & DEC/MEC (Herschel), MIRI (JWST), UVS

SMA (JUNO), SWAP & LYRA (PROBA-2), EUI (Solar Orbiter), ASPCIIS

(6)

Outline

What we do at CSL?

Solar Orbiter

EUI

(7)

Solar Orbiter key figures

ESA M-Class mission S/C currently in CDR Oct-2018 launch

0.28AU perihelion (17.5kW/m²), 1.47AU aphelion 6 remote sensing instruments

4 in-situ instruments

~1800kg S/C (~190kg payload) ~1kW

(8)

Outline

EUI

(9)

The

E

xtreme-

U

ltraviolet

I

mager

Remote sensing instrument with 3 channels

2 High Resolution Imagers (100km resol.)

– HRI_Lya at Lyman-α _{line (1216Å)}

– HRI_EUV at 174Å

1 dual-band Full Sun Imager at 174Å and 304Å (900km resol.)

FSI channel

HRI_Lyachannel

HRI_EUV channel

HRI_EUV entrance baffle HRI_Lyaentrance baffle FSI entrance baffle

HRIs Focal Plane Assembly FSI Focal Plane Assembly

(detector + Front End Electronics) FSI filter wheel

FSI primary mirror

HRIs primary mirror

HRIs secondary mirror

(10)

EUI in a nutshell

860 x 450 x 360 mm, ~15kg, 28W

CFRP-Alu honeycomb-CFRP sandwich structure

Ultrathin HRI_EUV & FSI entrance filters (150nm thick Al.)

MgF₂ coated HRI_Lya entrance filter

Al. coated CFRP entrance baffles

Heat-pipes to cool down entrance filters, baffles and doors

(11)

S/C thermal interfaces

S/C -y panel (conductive environment) S/C Heat Shield S/C heat shield Feedthrough Honeycomb bench HRI FPAs FEE detector HE CE_HRIs ME_HRIs

HRIs entrance baffle, door, filter assembly

FSI FPA CE_FSI ME_FSI Radiative environment Q_S Q_B FEE detector

HE: Hot Element interface (+50°C) CE: Cold Element Interface (-50°C)

ME: Medium Element Interface (+20°C)

Q_B: IR load from S/C heat shield feedthroughs at ~300°C

Q_S: Solar heat flux (17.5kW/m² at 0.28AU)

T_R: S/C cavity radiative environment (+50°C) T_SRP: S/C conductive environment (+50°C)

(12)

HRIs heat pipes

Conducts heat from HRIs filters, baffles & doors to HE Two redundant heat-pipes

Al-NH₃ heat pipes with H-shaped copper brazed interfaces

Copper goggles connecting doors, baffles, filters to HP Instrument orientation in TB test (also at S/C level)

(13)

Ultrathin HRI

_EUV

entrance filter

108 _{rejection of visible part of Solar spectrum}

Twice reinforced for structural & thermal

– Local Nickel mesh grown onto Al foil – Clamped between Al. frames

Ni mesh Frame cell Aluminium frame 2mm thick Aluminium frame ~30µm thick Ni mesh Frame pattern matching 150nm thick Aluminium foil

(14)

Detector &

F

ocal

P

lane

A

ssembly

3k x 3k Active Pixel Sensor (developed for EUI)

Aluminum nitride package (T° _{uniformity + CTE matching)}

(15)

Outline

EUI

Test setup presentation

Test results

(16)

Thermal balance test setup overview

Instrument STM upside-down 3 Xe lamps

3 feedthroughs 220 sensors

(17)

Illumination setup

3 elliptical Cermax Xe arc-lamp + parabolic folding mirror Lamp spectrum + mirror spectral reflectivity

Instrument coating absorptance adjusted

400 600 800 1000 1200 1400 1600 1800 2000 0 0.5 1 Wavelength [nm] re la ti v e s p e c tr a l in te n s it y [ A U ] 400 600 800 1000 1200 1400 1600 1800 2000 0 50 100 Wavelength [nm] In te g ra te d i n te n s it y [ % ] ∫E_Cermax(λ)dλ ∫E_Sun(λ)dλ

(18)

Illumination setup callibration

Profile measured with picture & photodiode mapping Intensity measured with pyranometer

(19)

17.5kW/m² @ 1.5m

1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 5 10 15 20 25 30 35 40 Ir ra d ia n c e [ k W /m ²]

Distribution over a 50mm diam area

Avg Max Min 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2 5 6 7 8 9 10

distance from mirror [m]

N o n u n if o rm it y w rt a v e ra g e [ % ] (Max-Avg)/Avg (Avg-Min)/Avg

Distance from folding mirror [m] Distance from folding mirror [m]

17.5

Irradiance [kW/m²]

Non-uniformity

(20)

Divergence from pinhole spot size

0 50 100 150 200 250 300 350 400 0 50 100 150 200 250 300 350 50mm 50 100 150 200 250 0.2 0.4 0.6 0.8 1 X: 35.63 Y: 0.278 X: 41.8 Y: 0.2815 M1 Array of pinholes screen penumbra atan Δ 2 atan 2 1.4 . . deg

(21)

Thermal IF setup

LN₂ panel + straps with heaters to provide CE, ME & HE temperatures

S/C cavity conductive environment

S/C heat shield

representative feedthrough (hot & cold) with ceramic heaters & LN₂ lines

(22)

Outline

EUI

Test setup presentation

Test results

(23)

Test sequence & results overview

01/09 01/10 01/11 01/12 01/13 01/14 -200 -100 0 100 200 300 400 500 Time T e m p e ra tu re [ °C ] Baffle_EUV_front_-Y THERMAL_IF_PANEL_1 Feedthrough_EUV_heater1_north FPA_FSI_APS_1 08-Jan-2014 12:00:00 14-Jan-2014 00:00:00 close vacuum chamber and pumping

Thermal shroud PID tuning

Start hot case - 1 Fuse broke up - 1 S/C Heater lost

Switch ON lamps to 17.5kW/m²

Switch to LN2 on radiator and wait stabilization

- ≠_{OP cases}

- Rotation of the instrument:

Heat pipe stall

- Hot NOP case - 3SC case

- Start cold OP case

- ≠_{OP cases}

- Start cold NOP case

Back to ambient P and T

HRI_EUVentrance baffle Thermal IF panel HRI_EUVfeedthrough FSI detector

(24)

Outline

EUI

Test correlation

(25)

Thermal model description

Semi-transparent screen to model lamp flux non-uniformity

Actual divergence Actual absorption 5219 nodes

HRI_Lya flux Solar transmissivity

0 0.65

(26)

Thermal model correlation

RMS error (93 sensors): 1.2K (4.8K before correlation) Error max: 2.8K

Hot OP case results:

Temperature [°C] 88 45 63 75 200

(27)

Test heat balance

14.0W environment input, 10W dissipation

QSRP = 0.0 W QS [W] QB [W] pupil 1.0 baffle 1.0 7.7 W VIS filter 3.4 1.0 W IR QR = 3.9 W door housing 2.3 QI 10.0 W pupil 0.7

baffle 0.4 3.7 W VIS QCE,HRIs = 4.8 W

filter 1.7 0.5 W IR

door housing 0.9 QS+QB Q TOT

14.0 W 24.0 W

pupil 0.4

baffle 0.0 0.5 W VIS

filter 0.0 0.0 W IR QME,HRIs = 2.9 W

door housing 0.0

Stru (goggles) & MLI 0.3 0.3 0.6 W Total 12.1 W + 1.8 W = 14.0 W QHE = 8.7 W 1.0 HRI EUV 8.7 W QME,FSI = 1.4 W HRI Lya 4.2 W QCE,FSI = 2.3 W FSI 0.0 0.5 W 0.5 IN OUT

(28)

Outline

EUI

Test correlation

(29)

Conclusions

Model correlated

Ultrathin filters survived

Hot & cold thermo-elastic measurement performed & correlated

Lessons learned for QM and FM thermal tests Further unit dedicated test:

– Focal plane assemblies QM – Doors QM

(30)

Thank you for your attention…

(31)

Contact

Lionel Jacques, ljacques@ulg.ac.be Thermal Engineer & PhD student

Centre Spatial de Liège Liège Science Park

Avenue Pré-Aily

B-4031 Angleur Belgium http://www.csl.ulg.ac.be University of Liège

Space Structures and Systems Lab 1, Chemin des Chevreuils (B52/3) Liege, B-4000, Belgium