1. Mechanical Design of the Fabry-Perot Spectrometer for Balloon Flight
By: Mohammed Kagalwala
Faculty: Lassonde School of Engineering
Dept. : ESSE
Supervisor: Dr. Jinjun Shan

2. “We do not inherit the Earth from our fathers; we are borrowing it from our children” ~ Lester Brown, environmentalist

3. Contents Background My Role Design Criteria Challenges Final Design
Design to Construction

4. Mission Objectives Outcomes
To obtain accurate, detailed, and collocated measurements of A-band oxygen at km
To retrieve simultaneously surface pressure, aerosol information, and surface albedo from the measurements
Outcomes
The O2 measurement provides information on the surface pressure, which is needed to develop accurate column measurements of gases like CO2 and CH4

5. Mission Briefing
Spectrometer will be flying on a high altitude balloon from Kiruna, Sweden at the end of August
Fig.1 – Atmospheric division,UCAR1

6. Mission Briefing
Fig.2 – Fabry- Perot (F-P) optical spectrometer made by MPB2

7. Mission Briefing Fig.3 – PI Amplifier Fig.4 – PI Amplifier network
Fig. 5- PC104

8. My Role
Primary Duties
Design and assembly of mechanical structure for optical and electrical system
Perform structural simulations in NX
Secondary Duties
Design electrical system to power electronics and instruments
Assist in thermal management and Arduino health system

9. CSA Requirements
Table 1 – List of CSA requirements based on gondola structure
Criteria Type
Criteria
Dimensions
Optical System: 300mm x 300mm x 750mm
Electrical System: 150mm x 200mm x 200mm
Gondola Mass
<200kg
Deadline
July

10. Payload Requirements Table 2 – List of payload requirements
Criteria Type
Criteria
Operational Pressure
1 atm
Spectrometer Temperature
25°C - 27°C
CCD Cooling
Ensure CCD temperature remains cool

11. Pressure
Problem
Due to capacitors on the F-P and PI Amplifiers, the operability of system is under question in vacuum conditions
Solution
Build entire system inside a sealed container

12. Pressure Interior Pressure: 1 atm Exterior Pressure: 0.08 atm
Stress Range:
1.42 MPa – 1.88 MPa
Interior Pressure: 1 atm
Exterior Pressure: 0.08 atm
Stress Range:
4.45 MPa – MPa
Fig.6 – Structural simulation results

13. CCD Cooling
Problem
Inside a sealed container, small fans will not be able to create enough circulation according to simulation, thus will not be able to cool CCD properly
Fig.7 – CCD fans
Solution
Replace fans with copper blocks and to use conduction as primary heat transfer mechanism

14. CCD Cooling
Fig.8 – CCD copper blocks for conduction

15. Temperature
Problem
F-P spectrometer operation temperature should be 25-27°C, due calibration environment
At 30 km the avg. temperature ranges from -20 °C to -40 °C. According to CSA thermal simulations, inside our optical tube the temperature will range from 0 °C to 16 °C.

16. Temperature
Fig.9 – Thermal simulation with copper blocks, CSA

17. Temperature
Solution
Localized heating and insulation around the spectrometer
From thermal simulations we found three 10” heater strips evenly spread around the spectrometer gave the best heating results.
Using FR4 to isolate the spectrometer from rest of the system
Paint exterior surfaces white to prevent overheating

18. Temperature Fig.11 – Thermal insulation rings Fig.10 – Thermal results
Fig.12 – F-P with thermal insulation rings

19. Weight Problem After implementing our solutions we were overweight
Cut section from structure components to reduce weight

20. Weight
Fig.13 – Weight reducing implementations

21. Final Design Electrical Box
Fig.15 – Interior views
Fig.14 – Exterior views

22. Final Design Optical System
Fig. 16 – Side-side comparison of real setup to model

23. Final Design Skeleton Structure
Fig. 17 – Component layout on skeletal structure

24. Final Design Optical Tube
Fig. 18 – Tube interior and exterior

25. Constructed Electrical Box
Fig. 19 – Electrical box exterior
Fig. 20 – Electrical interior

26. Heating and Health Fig. 21 – F-P heaters
Fig. 22 – Thermal control and health system

27. Constructed Skeleton Structure
Fig.23 – Components mounted to structure

28. Constructed Optical Tube
Fig.25 – Top face
Fig.24 – Side face
Fig.26 – Nadir face

29. Gondola Fitting
Fig.27 – Gondola fitting, CSA

30. Special Thanks
To the CSA, Lassonde School of Engineering, and SDCN Lab for this opportunity

31. References
The Stratosphere. Digital image. UCAR Center for Science Education. N.p., Web. 09 Aug <
MPB. “FAST FP Project Status.” Toronto, Canada. 24 Feb PowerPoint Presentation