Harding Flying Bison RockSat-C 2012 Team Critical Design Review

1. Harding Flying Bison RockSat-C 2012 TeamCritical Design Review Harding University Bonnie Enix, Joshua Griffith, Will Waldron, Edmond Wilson, David Stair 28 November 2011

2. Mission Overview Bonnie Enix

3. Mission Overview – Mission Statement Design, build, test and fly a spectrometer that will measure visible and near-infrared spectra of gases in Earth’s atmosphere at lower altitudes and the Sun’s irradiance at high altitudes Tabulate and interpret spectra and create a technical report summarizing the results obtained and conclusions reached

4. Mission Overview – Mission Requirements Requirements 1. An optical port is mandatory 2. An adequate, stable and reliable power supply 3. A robust, responsive G-Switch 4. A sensitive, rugged spectrometer operating in the 200 – 1000 nm wavelength range • A photodiode sensitive to the same wavelengths as the spectrometer • A microprocessor with two programmable clocks, high speed analog to digital converters, and memory to store the acquired spectra

5. Mission Overview – Mission Requirements Requirements - continued 7. Power distribution board to allocate the correct voltages and currents to each device requiring power 8. Signal conditioning board to insure the electrical inputs and outputs between the sensors and the microprocessor match in terms of voltage ranges, currents and impedances 9. Software program to operate the payload 10. Mounting hardware for the payload that will withstand the g-forces imposed during testing and flight and will not interfere with the Frostburg State University payload

6. Mission Overview – Science Questions Science questions to be answered: 1. What atoms and molecules can be identified in the spectra acquired by our spectrometer during the flight? 2. What are the concentrations of these substances? 3. Can the lineshapes of the oxygen and water spectra be used to reveal the altitude, temperature and number density of each gas? 4. Is this spectrometer system accurate, sensitive, useful and robust enough to be deployed on future Solar System missions?

7. Mission Overview – Benefits and Use of Results This project fits into a larger program to build a suite of spectrometers to be deployed on a mobile robotic vehicle on the surface of Mars The spectrometers will be used to detect, measure, and pinpoint the location of biomarker gases on Mars (if they exist) and to gain new information about the atmosphere of Mars to evaluate regions of habitability for human exploration Successful completion of this mission will provide a heritage for the spectrometer as we move up the TRL ladder seeking approval for inclusion of this instrument on a future Solar System mission A comprehensive technical report will be created and an oral summary prepared for presentation at a technical meeting

8. Mission Overview – Concepts With the spectrometer located inside the Earth’s atmosphere, the Sun’s light can be used as the optical light source in obtaining transmission spectra of Earth’s atmosphere I0 I Computer with Data Storage Spectrometer Atmospheric Gases Sun

9. Mission Overview – Concepts Once above Earth’s atmosphere, the spectrum of the Sun’s surface can be measured without interference. I0 Computer with Data Storage Spectrometer Sun

10. Mission Overview – Concepts The spectrometer measures atmospheric spectrum through optical port in rocket airframe using Sunlight as the source. Any gases that absorb radiation in the 200 to 1100 nm range will contribute to the acquired spectra.

11. Mission Overview – Concepts Percent of atmosphere below rocket as a function of flight time. The flight will be above the atmosphere for about half the flight.

12. Mission Overview -- Concepts We can definitely measure water and oxygen! Spectrum of Earth’s atmosphere at sea level over a 10 km path. Water (green) and oxygen (blue) dominate the atmospheric spectrum in the region of 200 to 1080 nm -- the range of our instrument. Spectrum created from HITRAN 2008 Database and HITRAN-PC software.

13. Mission Overview – Concepts oxygen water Spectrum of Earth’s atmosphere at 297 ft. above sea level measured with flight spectrometer. Water and oxygen peaks are clearly visible. Blue trace made with spectrometer pointed to bright clear sky away from Sun. Red trace made with instrument pointed directly at the Sun

14. Mission Overview – Theory Transmittance of light through a sample obeys the Beer-Lambert Law I(ν) I0(ν) Spectrometer Sample I0(ν) Intensity of radiation incident on the sample I(ν) Intensity of radiation of frequency, , after passing through sample Absorption Cross Section at frequency, , cm2/molecule Number of absorbing molecules per volume N L Sample path length

15. Mission Overview – Concept of Operations Altitude t ≈ 4.0 min Altitude: 95 km t ≈ 1.7 min Altitude: 95 km Apogee t ≈ 2.8 min Altitude: ≈115 km t ≈ 4.5 min Altitude: 75 km t ≈ 1.3 min Altitude: 75 km t ≈ 0.6 min Altitude: 52 km t ≈ 4.8 min Altitude: 52 km Rocket re-enters atmosphere End of Orion Burn Rocket above atmosphere When G-switch activates payload, spectra will be measured at a frequency of 2.0 Hz producing 1200 spectra in 10 minutes t ≈ 5.5 min Chute Deploys 0 min Time t ≈ 15 min Splash Down G switch triggered -- All systems on -- Begin data collection

16. Mission Overview – Expected Results G-Switch will function properly to turn on electronics Batteries will be sufficient to power the payload for 20 minutes Instrument will perform well and at least 100 useable spectra will be recorded, 50 in the atmosphere and 50 above the atmosphere Concentrations of water vapor and oxygen will be measured as a function of altitude Ozone will be measured at higher altitudes Other atmospheric pollutant gases may be detected

17. Design Description Will Waldron

18. Mechanical Design Elements Microcomputer G- Switch Electronics board Spectrometer Photodiode on top Light gathering lens on bottom SolidWorks rendering of spectrometer payload mounted in top half of canister using optical port to right of wire-way as viewed from top or bottom of rocket.

19. Mechanical Design -- Spectrometer Light enters spectrometer through fiber optic cable in the front of the instrument, goes through a slit and strikes the round mirror facing front. From there the light is directed to the diffraction grating (mounted on hemi-cylinder) which diffracts the light onto the collimating mirror on the left of the instrument and then to a CCD array detector. A plastic filter in front of the CCD array removes unwanted spectral orders

20. Mechanical Design Elements Cut away portion of payload diagram showing spectrometer mounted on main mounting plate and with cover removed from spectrometer. Fiber optic cable also removed. Spectrometer has no moving parts and is mounted in a sturdy aluminum optical bench.

21. Mechanical Design Elements Spectrometer payload occupies exactly half the vertical space of the canister. In order to mount all the components, two aluminum mounting plates are required. One-half inch stainless steel standoffs are used to secure the payload to the top of the canister using 8-32 stainless steel socket head cap screws.

22. Mechanical Design Elements TERN Model EL Microprocessor with 2 gigabyte compact flash memory G-Switch Battery compartment holding five 9-volt alkaline batteries View of 1/8 inch thick top mounting plate with components. Electronics board is mounted under the microprocessor board.

23. Mechanical Design Elements Side view of payload showing positioning of spectrometer with attached fiber optic cable. Fiber optic cable is terminated with light collecting lens aimed at rocket viewport. Photodiode is mounted above light collecting lens. Batteries, G-switch, microprocessor and electronics board mounted on secondary plate.

24. Mechanical Design Elements Changes since PDR: • The only change since PDR is the decision to leave off the accelerometers from the payload. • The purpose of the accelerometers was to provide accurate knowledge of the rocket view port direction at each instance • of the rocket flight. • It was realized that obtaining this information would require time and effort beyond our time budget. • The same information can be obtained from the flight data • WFF will record during flight.

25. Electrical Design – Overall Schematic We have not completed our detailed schematic at this time.

26. Electrical Design – G-Switch Circuit We have decided to use the RockOn workshop G-switch circuit. We have studied the schematic for it and are making inroads into exactly how it works.

27. Software Design The program starts with a power-on reset on microprocessor. The initial real time clock reading is taken and stored to determine the length of time for the data collection. Begin iterations by storing the real time clock, photodiode reading and 2048 pixels of the CCD Linear Array.

28. Software Design – Major Inputs and Outputs Timing diagram for spectrometer operation. Top two traces show timing relations for the two clocks that clock the data out of the spectrometer. Bottom trace is the 2048 pixel data output for one complete spectrum. Two DACs are need for clocking and two ADCs are required to read the spectrometer and photodiode sensors for each clock cycle.

29. Prototyping/Analysis Joshua Griffith

30. Prototyping Results • Our prototyping is being carried out by exhaustive SolidWorks modeling of our • payload. • The spectrometer has been operated and spectra of the sky have been recorded successfully

31. Prototyping Results -- Mass

32. Prototyping Results -- Power Budget

33. Prototyping Results Mass, volume and power analysis The total allowed mass for a canister including its payload is 20.0 lbf. The canister has a mass of about 6.7 lbf. If the remaining mass is divided equally between two teams, each team will have 6.65 lbf. Our payload has a mass of 5.97 lbf. We have ample room for mounting our instrument and power supply in the volume allocated (1/2 canister) Our energy requirements can be amply met with several 9 VDC batteries. Our current consumption is 260 mA. One 9 VDC battery would last 1.25 h at this drain rate

34. Manufacturing Plan Will Waldron

35. Manufacturing Plan • Items to be constructed: • 9 in. x 0.25 inch circular aluminum plate • 9 in x 0.125 inch circular aluminum plate • G-switch brackett • Battery holder for 5 9-volt batteries • All other items have already been acquired • Manufacturing of the above four items will be done in January/February

36. Electrical Elements • Items to be manufactured • Cable to connect spectrometer CCD array electronics to power and to • Microprocessor • Connections between battery stack, G-switch, WFF RBF wires, • Microprocessor and spectrometer • G-switch circuit • All items to needed for electrical circuits are in place • Manufacturing of these items will take place in January/February

37. Software Elements • No computer code has been written at this time • We are working on learning to use the TERN Development System software • to carry out analog to digital and digital to analog conversion and data • storage and retrieval. • It is estimated that most of January – April 2012 will be needed to perfect the • software.

38. Testing Plan Will Waldron

39. System Level Testing • Tests have already been successfully carried out with the spectrometer • And these tests will continue until we have completed a successful flight • simulation test. • The G-switch circuitry will be tested many times once the electronics • board is fabricated. • After the software becomes somewhat operational, testing of the • Instrument under a variety of sunlight/cloudy conditions will proceed until • the instrument can respond satisfactorily to a wide range of sky conditions. • Power supply testing will be carried out to insure the instrument has an • adequate amount of current/voltage capability plus a reserve.

40. Software Testing • Testing of the system to produce the two clock timing pulse trains required • will be carried out by feeding the output pins of the two DACs to a two-channel • oscilloscope to evaluate the frequencies, voltages and synchronous behavior • desired. • Testing of the system to acquire the voltages produced by the two sensors, • the photodiode and the CCD array, will be carried out by first feeding the • outputs of these two transducers to an oscilloscope to make sure the signals • to be measured are actually being produced as well as what the voltage • and frequency ranges are. • Then the software will be tested to see if this same data can be read in via • the two ADCs to the memory on board the microprocessor and then read out • into a spreadsheet file.

41. Risks Josh Griffith

42. Risk Walk-Down

43. Risk Walk-Down • Risks: • G-switch malfunction • Batteries drain early • Microprocessor not started • Cloud cover to thick • Sun too low on horizon • Mitigation: • Testing the system with many • trials is the only reasonable • way to minimize failure

44. User Guide Compliance Bonnie Enix

45. User Guide Compliance • Mass of payload plus canister is 13.4 lbf • CG within 1”x1”x1” envelope? – Information not available yet • Batteries? 5 9-Volt Alkaline, non rechargeable batteries • One optical port required • G-switch activation at time of launch is the method chosen

46. Sharing Logistics • We are sharing our canister with Frostburg State University • Plan for collaboration We communicate by e-mail and RockSat-C website We will send a copy of our CDR to Frostburg and request a copy of their CDR • We plan to joining our payload to Frostburg’s with stainless steel standoffs. grandpmr.com

47. Project Management Plan Bonnie Enix

48. Bonnie Enix Software & Testing • Joshua Griffith Software & Testing • Will Waldron Hardware & Electronics Project Management – Organizational Chart • David Stair Technician & Graphic Artist • Edmond Wilson Mentor & Logistics

49. Project Management Plan

50. Project Management Plan