Lagrange Remote Sensing Instruments: the Extreme Ultraviolet Imager (Euvi)

1 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Mission overview

4 remote-sensing instruments See Poster 23 by J. Davies

2 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Mission overview

5 in-situ instruments

3 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Mission overview

• Overall Remote Sensing Instruments leader: RAL Space (UK) • EUVI study led by three institutes: – CSL (BE) – ROB (BE) – PMOD/WRC (CH)

• CSL activities • ROB activities • PMOD activities – EUVI Instrument manager: – instrument – electrical engineering • Overall management requirements – mechanisms • System study – instrument operation – mechanical engineering • Optical engineering – ground segments • Thermal engineering • AIT engineering

• Roles & Responsibilities – BPI: Pr. Dr. Serge Habraken (CSL) – Bco-I: Dr. Matthew J West (ROB) – CSL work funded by Belspo via Prodex Programme

4 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Mission overview

• EUV Imager – SSA programme (SWE) – Location: L5 – Goal: image the full solar disc – Waveband: EUV wavelength (e.g. 193 Å) – Heritage: PROBA-2 SWAP ESIO (GSTP) Solar Orbiter EUI

Parameter Requirement Spectral resolution < 1.5 푛푚 퐹푊퐻푀 Spatial resolution < 5 푎푟푐푠푒푐 Field of view 42.6′ 푥 42.6′ Mass < 8 푘푔 Size < 600 푥 150 푥 150 푚푚 Power < 10 푊

5 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Instrument overview

• Selected wavelengths

131 nm 19.5 nm 30.4 nm

Semi-Static Structures Dynamic structures Regions

Filaments/Prominences Flares Chromosphere Active Regions Eruptions Million Degree Corona Coronal Holes EUV Waves Dimmings

6 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Instrument overview

• Field of view

– Differs between selected wavebands

1. 195 Å

43 arcmin Toward Earth

62 arcmin

2. 131 + 304 Å

43 arcmin

7 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Instrument overview

• Detector: EUI spare 3k by 3k, separate windowing options 1. 195 Å: 2300x1600, 1,6”/pixel, 3.2” spat. res. over 2 pixels 2. 131 + 304 Å: 2x2 binning, 800x800, 3.2”/pixel, 6.4” spat. res. over 2 pixels

• Cadence: Different for each spectral channel 1. 195 Å: 3 min 2. 131 Å: 2 min 3. 304 Å: 5 min • Schematic configuration:

Channel 1 FEE DC/DC Entrance f ilter FPA camera

Detector PE Power Optical sy stem Door

Channel 2 Entrance f ilter Filter wheel FPA camera

Detector PE

Optical sy stem Door HK, data Mechanism EUVI Optical Unit control TC

EUVI Electronic Box IPU

8 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Instrument overview

• Obtained design

– ESIO-like truss structure

• Separate avionic box

• Lightweight and stiff – SWAP-based optical design

• Improved spatial resolution and larger FOV wrt SWAP (and ESIO)

• Similar baffling system – Filter wheel

• Selects between 131 and 304 observation – One-shot opening doors

9 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Performed analyses

• Performed analyses

– Understanding of requirements

– Optical design

• Tolerancing

EUVI Electronics IPCU

Optical Unit • Straylight Heater TL 2*(1) EUVI Survival Heater RadiatorLink Radiator Thermal Link Thermistor TL 2*(1) EUVI Thermistor RadiatorLink

Camera 1 SpW 2*(1) EUVI-A CCSDS SpW 2*(1)

Heater APS(A) 2*(1) EUVI Operational Heater APS (A)

Thermistor APS(A) 2*(1) EUVI Thermistor APS (A)

Camera 2 SpW 2*(1) EUVI-B CCSDS SpW 2*(1)

Heater APS(B) 2*(1) EUVI Operational Heater APS (B) – Electrical design Thermistor APS(B) 2*(1) EUVI Thermistor APS (B) Power EB HK Control

EB HK Control

Filter Wheel Power

Electronic Box – Instrument performance model Power 2*(1) EUVI SU 2*(1)

Heater EB 2*(1) EUVI Survival Heater EB

Thermistor EB 2*(1) EUVI Thermistor EB – Thermal analysis:

• Undergoing at CSL

– Structural analysis

• Undergoing at PMOD/WRC

10 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Performed analyses

• Encountered issues:

– Coating: dual-band coating for 131 + 304 Å is not “off-the-shelf” because those two wavelengths do not fall within two successive Bragg orders (need to be factor ~2 between wavelengths)

• is feasible

• requires simulation and development

Other alternatives:

• Superpose 2 mono-band coatings on top of each other

• Implement a patterned coating on primary mirror

will lead to ~50% loss in efficiency BUT mono-band coating may be as high as 2x more efficient than dual-band.

11 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Way forward after PRR

12 ESWW 2018, 9 Nov. 2018 LGRRS-EUVI | Conclusion

13 ESWW 2018, 9 Nov. 2018