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SwissCube Project Phase B March 8, 2007 N. Scheidegger | 8 March 2007 © 2007 EPFL | UNINE | HES-SO EPFL - LMTS N. Scheidegger Science Payload.

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Presentation on theme: "SwissCube Project Phase B March 8, 2007 N. Scheidegger | 8 March 2007 © 2007 EPFL | UNINE | HES-SO EPFL - LMTS N. Scheidegger Science Payload."— Presentation transcript:

1 SwissCube Project Phase B March 8, 2007 N. Scheidegger | 8 March 2007 © 2007 EPFL | UNINE | HES-SO EPFL - LMTS N. Scheidegger Science Payload

2 © 2007 EPFL | UNINE | HES-SO 2 Science Objectives Measure the airglow emission in the upper atmosphere at 100 km altitude to : Demonstrate the feasibility of using airglow as a basis for a low-cost Earth Sensor Validate the established airglow model or bring additional information about airglow dependence on latitude altitude local solar time Nightglow and aurora borealis

3 Science Payload © 2007 EPFL | UNINE | HES-SO 3 Earth Appearance at 762 nm for different Solar Local Times Min 24:00 SLTMean 24:00 SLTMax 24:00 SLT Min 06:00 SLTMean 06:00 SLTMax 06:00 SLT Min 12:00 SLTMean 12:00 SLTMax 12:00 SLT

4 Science Payload © 2007 EPFL | UNINE | HES-SO 4 Expected airglow at 700 km altitude MinMeanMax Zenith At night150370750 At day9 k22 k90 k Limb At night30 k75 k150 k At day1.8 M450 M180 M Airglow [photons/pixel/s] * *for an aperture of Ø4 mm and a FOV of 0.16°/pixel = minimum photon flux

5 Science Payload © 2007 EPFL | UNINE | HES-SO 5 Driving Requirements Payload may be a technology demonstrator of the Earth Sensor based on airglow –Observes the emission at 762 nm with a bandwidth of at least [10] nm –Has a spatial resolution of at least [0.3]° and a FOV of at least [20]° –Observes the airglow with a CMOS SPAD array if possible –Survives having its boresight directly sun pointing for a period of at least 10 hours –Can perform science mission with the sun no closer than [30]° from its boresight. Physical constraints –Volume: [30 x 30 x 70] mm 3 for optics and detector [70 x 30 x 20] mm 3 for mainboard –Mass: [60] g –Power: [450] mW, during [10]s for each image

6 Science Payload © 2007 EPFL | UNINE | HES-SO 6 Science Payload Instrument Design mainboard headboard detector optical system filter baffle

7 Science Payload © 2007 EPFL | UNINE | HES-SO 7 Design Description Detector and control electronics –Detect photons and generate digital output which is proportional to local light intensity –Provides required power and control signal for the detector –Interfaces with CDMS and ground station Optical system –Magnifies the image –Filters the selected airglow line –Protects detector from sun –Links the detector mechanically to the satellite bus

8 Science Payload © 2007 EPFL | UNINE | HES-SO 8 Detector PerformanceUnitMT9V032KAC-9619SPAD Array sizepixels188 x 120 162 x 122 128 x 128 Pixel pitchμmμm24 x 24 30 x 30 Total FOV°29.4 x 18.831.6 x 23.825 x 25 Dynamic rangedB100110140 Fill-factor%204715 Photon Detection Probability %45275 Dark Counts (at 25° C)Hz4 k3.5 k25 Power consumptionmW320170??? Detected airglow signal at limb at night counts/pixel/s4 k – 19 k6 k – 29 k350 – 1.7 k Detected airglow signal at limb at day counts/pixel/s227 k – 2.3 M354 k – 3.5 M21 k – 209 k * for an aperture of Ø4 mm and a total FOV of 25° for a SPAD array = current baseline design including a Binning of 4 x 4 pixels

9 Science Payload © 2007 EPFL | UNINE | HES-SO 9 Optical System: Design Parameters ParameterUnitPossible Values Targeted Design Remarks (Limiting parameters) Total FOV°22 – 30Required FOV to guarantee limb detection with a attitude determination of 10° FOV per pixel°< 0.23Required resolution for ES operation Aperture Ømm 6SNR > 3 for limb measurements Focal LengthmmDetermined by aperture, pixel pitch and FOV per pixel Pixel Pitch ( = pitch of the microlenses for the SPAD- array) μmμm24 /30Size of a pixel of a CMOS/SPAD For the SPAD-array: Size of the Active Spot of the pixel μmμm6 – 9DCR < 25 Hz Massg 30SwissCube mass budget Volumemm Ø 30 x 50 SwissCube volume budget FilternmTBDcentered at 762 nm BafflemmTBDprotect the detector from sun radiation no closer than [30]° from its boresight Max. optical losses%< 50%vignetting

10 Science Payload © 2007 EPFL | UNINE | HES-SO 10 Optical System: Baseline Design ParameterUnitPossible Values Targeted Design Remarks (Limiting parameters) Total FOV°25Required FOV to guarantee limb detection with a attitude determination of 10° FOV per pixel°0.2Required resolution for ES operation Aperture Ømm6SNR > 3 for limb measurements Focal LengthmmDetermined by aperture, pixel pitch and FOV per pixel Pixel Pitch ( = pitch of the microlenses for the SPAD- array) μmμm24 /30Size of a pixel of a CMOS/SPAD For the SPAD-array: Size of the Active Spot of the pixel μmμm6DCR < 25 Hz Massg30SwissCube mass budget VolumemmØ 30 x 50 SwissCube volume budget Filternm[10]centered at 762 nm BafflemmTBDprotect the detector from sun radiation no closer than [30]° from its boresight Max. optical losses%50%vignetting

11 Science Payload © 2007 EPFL | UNINE | HES-SO 11 Diploma project: Design of a Telescope for the SwissCube Picosatellite Understanding of the science and project requirements on the payload Optical design for the payload Opto-mechanical design for the payload, including selection of material for lens and support structure Assembly of the overall payload subsystem based on the CMOS detector Testing and verification of the optical properties of the payload Documentation, preparation of end-of-phase review. (Electrical design for the CMOS detector control) (Establishment of hardware, data flow and cabling block diagrams for the payload subsystem, including connection with the other subsystems) (Testing and verification of the electrical, power and sensitivity performance of the detector)

12 Science Payload © 2007 EPFL | UNINE | HES-SO 12 My inputs: Filter design (1.5.07) Determination of the interface with the CDMS sub-system (1.4.07) (Electrical design for the CMOS detector control) (1.5.07) (Establishment of data flow and cabling block diagrams for the payload subsystem, including connection with the other subsystems) (1.5.07)

13 Science Payload © 2007 EPFL | UNINE | HES-SO 13 Planned meetings and reports: 1 x per month with the whole payload subsystem team Every week: each student reports briefly his/her last analyses and results (1 A4 page)

14 Science Payload © 2007 EPFL | UNINE | HES-SO 14 Questions ?

15 Science Payload © 2007 EPFL | UNINE | HES-SO 15 PL microcontroller: –Guarantees a standard interface between the detector and the CDMS subsystem or commands coming from the ground station CDMS subsystem: –Controls activation of the payload subsystem –Provides the parameters for the detector initialization (integration time, binning factor, DCR suppression factor,…) –Reads the science data directly form the detector –Does image compression if necessary –Formats science data according to the science data product –Stores the science data until transfer to the ground station CDMS – Payload Interface


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