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

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

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

Mission Objectives Outcomes To obtain accurate, detailed, and collocated measurements of A-band oxygen at 20-40 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

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

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

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

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

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 31 2016

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

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

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 – 15.45 MPa Fig.6 – Structural simulation results

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

CCD Cooling Fig.8 – CCD copper blocks for conduction

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.

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

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

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

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

Weight Fig.13 – Weight reducing implementations

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

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

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

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

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

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

Constructed Skeleton Structure Fig.23 – Components mounted to structure

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

Gondola Fitting Fig.27 – Gondola fitting, CSA

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

References The Stratosphere. Digital image. UCAR Center for Science Education. N.p., 2011. Web. 09 Aug. 2016. <http://scied.ucar.edu/shortcontent/stratosphere-overview>. MPB. “FAST FP Project Status.” Toronto, Canada. 24 Feb. 2016 PowerPoint Presentation