RockSat-C 2012 CDR Harding Flying Bison RockSat-C 2012 Team Critical Design Review Harding University Bonnie Enix, Joshua Griffith, Will Waldron, Edmond Wilson, David Stair 28 November

RockSat-C 2012 CDR Mission Overview 2 Bonnie Enix

RockSat-C 2012 CDR Mission Overview – Mission Statement 3 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

RockSat-C 2012 CDR Mission Overview – Mission Requirements 4 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 5.A photodiode sensitive to the same wavelengths as the spectrometer 6.A microprocessor with two programmable clocks, high speed analog to digital converters, and memory to store the acquired spectra

RockSat-C 2012 CDR Mission Overview – Mission Requirements 5 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

RockSat-C 2012 CDR Mission Overview – Science Questions 6 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?

RockSat-C 2012 CDR Mission Overview – Benefits and Use of Results 7 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

RockSat-C 2012 CDR 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 8 SunAtmospheric GasesSpectrometer Computer with Data Storage I0I0 I

RockSat-C 2012 CDR Mission Overview – Concepts Once above Earth’s atmosphere, the spectrum of the Sun’s surface can be measured without interference. 9 SunSpectrometer Computer with Data Storage I0I0

RockSat-C 2012 CDR Mission Overview – Concepts 10 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.

RockSat-C 2012 CDR 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.

RockSat-C 2012 CDR Mission Overview -- Concepts 12 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.

RockSat-C 2012 CDR Mission Overview – Concepts 13 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 oxygen water

RockSat-C 2012 CDR Mission Overview – Theory 14 Intensity of radiation of frequency, Intensity of radiation incident on the sample, after passing through sample Absorption Cross Section at frequency,, cm 2 /molecule N L Transmittance of light through a sample obeys the Beer-Lambert Law Sample path length Number of absorbing molecules per volume Sample I (ν)I (ν) I0(ν)I0(ν) I (ν)I (ν) I0(ν)I0(ν) Spectrometer

RockSat-C 2012 CDR Mission Overview – Concept of Operations t ≈ 1.3 min Altitude: 75 km t ≈ 15 min Splash Down t ≈ 1.7 min Altitude: 95 km G switch triggered -- All systems on -- Begin data collection t ≈ 4.0 min Altitude: 95 km Apogee t ≈ 2.8 min Altitude: ≈115 km End of Orion Burn Rocket above atmosphere t ≈ 4.5 min Altitude: 75 km Altitude t ≈ 5.5 min Chute Deploys When G-switch activates payload, spectra will be measured at a frequency of 2.0 Hz producing 1200 spectra in 10 minutes Rocket re-enters atmosphere t ≈ 0.6 min Altitude: 52 km t ≈ 4.8 min Altitude: 52 km 0 min Time

RockSat-C 2012 CDR Mission Overview – Expected Results 16 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

RockSat-C 2012 CDR Design Description Will Waldron 17

RockSat-C 2012 CDR Mechanical Design Elements 18 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. Photodiode on top Light gathering lens on bottom Spectrometer G- Switch Microcomputer Electronics board

RockSat-C 2012 CDR Mechanical Design -- Spectrometer 19 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

RockSat-C 2012 CDR Mechanical Design Elements 20 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.

RockSat-C 2012 CDR Mechanical Design Elements 21 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.

RockSat-C 2012 CDR Mechanical Design Elements 22 View of 1/8 inch thick top mounting plate with components. Electronics board is mounted under the microprocessor board. TERN Model EL Microprocessor with 2 gigabyte compact flash memory G-Switch Battery compartment holding five 9-volt alkaline batteries

RockSat-C 2012 CDR Mechanical Design Elements 23 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.

RockSat-C 2012 CDR Mechanical Design Elements 24 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. Changes since PDR:

RockSat-C 2012 CDR Electrical Design – Overall Schematic 25 We have not completed our detailed schematic at this time.

RockSat-C 2012 CDR Electrical Design – G-Switch Circuit 26 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.

RockSat-C 2012 CDR Software Design 27 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.

RockSat-C 2012 CDR Software Design – Major Inputs and Outputs 28 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.

RockSat-C 2012 CDR Prototyping/Analysis Joshua Griffith 29

RockSat-C 2012 CDR Prototyping Results 30 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

RockSat-C 2012 CDR Prototyping Results -- Mass 31 Mass Budget SubsystemTotal Mass (lbf) Main Al Plate1.57 Secondary Al Plate0.37 Spectrometer2.37 Batteries0.50 Battery holder0.34 Microprocessor 0.15 Electronics Board 0.20 Fiber Optic Cable 0.13 Standoffs0.34 Total5.97 Over/UnderUnder 0.68

RockSat-C 2012 CDR Prototyping Results -- Power Budget 32 Power Budget SubsystemVoltage (V)Current (A)Time On (min)Amp-Hours Microprocessor CCD Array Photodiode Total (A*hr):0.063 Over/UnderUnder 0.937

RockSat-C 2012 CDR 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 33

RockSat-C 2012 CDR Manufacturing Plan Will Waldron 34

RockSat-C 2012 CDR Manufacturing Plan 35 Items to be constructed: 9 in. x 0.25 inch circular aluminum plate 9 in x 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

RockSat-C 2012 CDR Electrical Elements 36 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

RockSat-C 2012 CDR Software Elements 37 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.

RockSat-C 2012 CDR Testing Plan Will Waldron 38

RockSat-C 2012 CDR System Level Testing 39 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.

RockSat-C 2012 CDR Software Testing 40 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.

RockSat-C 2012 CDR Risks Josh Griffith 41

RockSat-C 2012 CDR Risk Walk-Down 42 Consequence Entire mission fails Partial Mission failure Little to no data collected Once above clouds, measurements will be successful G-Switch doesn’t activate electronics Batteries drain before end of flight Microcontroller has malfunction Sunlight too low due to cloud cover Possibility

RockSat-C 2012 CDR Risk Walk-Down 43 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

RockSat-C 2012 CDR User Guide Compliance Bonnie Enix 44

RockSat-C 2012 CDR 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 45

RockSat-C 2012 CDR Sharing Logistics 46 We are sharing our canister with Frostburg State University Plan for collaboration We communicate by 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

RockSat-C 2012 CDR Project Management Plan Bonnie Enix 47

RockSat-C 2012 CDR Project Management – Organizational Chart 48 Bonnie Enix Software & Testing Joshua Griffith Software & Testing Will Waldron Hardware & Electronics Edmond Wilson Mentor & Logistics David Stair Technician & Graphic Artist

RockSat-C 2012 CDR Project Management Plan 49 Task – February 2012Week 1Week 2Week 3Week 4 G-Switch Implementation ◊ Compression Testing of Plates & Standoffs ◊ Power Distribution System ◊ Constructing 2 Aluminum Plates ◊ Interfacing Controller to Spectrometer Making and Producing Reports ◊◊

RockSat-C 2012 CDR Project Management Plan 50 Task – March 2012Week 1 Week 2 Week 3 Week 4 Week 5 Construction of Brackets & Fixtures to go on mounting plates ◊ Spring Break Assembling Payload Mechanical Spring Break ◊ Interfacing Controller to Spectrometer Spring Break ◊ Reporting and Making Reports Spring Break ◊

RockSat-C 2012 CDR Project Management Plan 51 Task – April 2012Week 1 Week 2 Week 3 Week 4 Week 5 Testing Fully Integrated System In Laboratory ◊ Using Atmosphere Models To Predict Results ◊ Carry Out Vacuum Tests ◊ Carry Out Temperature Tests ◊ Outside Testing ◊ Mass & Center of Gravity ◊ Making And Producing Reports ◊◊◊◊

RockSat-C 2012 CDR Project Management Plan 52 Task – May 2012Week 1 Week 2 Week 3 Week 4 Week 5 Day in the Life Testing #1 ◊ Day in the Life Testing #2 ◊ Outside Testing of Payload ◊ Final Testing of Electrical Shorts ◊ Final Testing of Center of Gravity and Mass ◊ Making And Producing Reports ◊◊◊◊◊

RockSat-C 2012 CDR Project Management Plan 53 Task – June 2012Week 1 Week 2 Week 3 Week 4 Week 5 Final Inspections, Integration and Testing ◊ Making And Producing Reports ◊◊ Travel to Wallops Island ◊ Visual Inspections at Wallops Island ◊ Vibration Tests and Integration at Wallops Island ◊ Launch Day! ◊◊◊◊◊

RockSat-C 2012 CDR Project Management – Budget 54 ItemAmountTotal Canister & Fees7000 Travel & lodging for launch week1800/person7200 Student Fellowship 8 weeks at 40 hr/wk 4000/student12000 Materials & Components1500 Total$27,700

RockSat-C 2012 CDR We believe we have a good workable plan. Our mentor has two years of experience in this program. We are looking forward to progressing rapidly starting at the beginning of the spring semester. We will be working on software familiarization and construction over the Holiday break. Conclusion 55