Microbial Detection Arrays Critical Design Review December 5th, 2006 Aerospace Senior Projects University of Colorado – Boulder Advisors: Dr. Forbes and Dr. Maslanik Customers: BioServe and Tufts University Jeff Childers Dave Miller Elizabeth Newton Ted Schumacher Shayla Stewart Steven To Charles Vaughan Sameera Wijesinghe

2 Briefing Overview Overview of Objectives and Requirements System Architecture Prototype Results Mechanical Design Elements Electrical Design Elements Software Design Elements Integration, Verification, and Test Plan Project Management Plan Appendices

3 Objectives Component of larger project –Future Mars astrobiology mission from BioServe/Tufts University/JSC –Astrobiology objective: electrochemical sensing of metabolic activity –Three components: biology (JSC), sensors (Tufts), instrument hardware (CU) MiDAs team objective: instrument hardware component –Design/build integrated field instrument with meaningful biological and spaceflight constraints –Validate key functions to enable field research –Extends proof-of-concept from lab to field Raise TRL from 1-3 to 4-5

4 TRL Objective

5 Deliverables Field-ready unit (TRL 4-5) Test data that verifies requirements Operational manual for use Document proposing design solutions to further raise the TRL (to 6-7)

6 Requirements Overview 1.Samples placed in autoclaves 2.Autoclaves heated to 121°C and held for 15 minutes 3.Autoclaves cooled to 20°C and held for 24 hours 4.Process may be repeated up to 3 times 5.Valves opened 6.Water pumped into autoclaves 7.Sample flushed into reaction chambers 8.Inoculation sample added to test chamber 9.Environmental chamber maintained between 4°C and 37°C 10.Mixers stir sample and water 11.Sample is tested for 14 days Water tubing not shown

7 Requirement Refinement Complete autonomy no longer primary goal –Increased reliance on experimenter to open valves and deliver inoculation sample –Instrument will not provide its own power Reason: –Change at request of customer – trades autonomy for reliability in field instrument –Autonomy adds expense, complexity, and failure modes without proving key concepts or raising TRL –Autonomy options will be included in design document –Key components maintained in field instrument

8 Mars/Earth Comparison Theoretical Mars MissionMiDAs Earth Based Apparatus Receive low power from RoverReceive low power from external source Receive startup command from uplinkPress power button Rover opens Autoclave lidPerson opens Autoclave lid Rover inputs samplePerson inputs sample Rover closes Autoclave lidPerson closes Autoclave lid Autoclave cycle beginsAutoclave cycle begins through SW run command Rxn chamber environment controls begin Valve opensPerson opens valve Water flushes sample out of autoclave Valve closesPerson closes valve Mixing beginsMixing begins through SW run command DAq beginsDAq begins through SW run command Inoculation sample addedPerson adds inoculation sample DAq runs for 14 days Data downlink from rover to satellite to Earth Data stored on-board, transfer to PC

9 System Architecture (External) Dimensions: 18” x 18” x 15” (46 cm x 46 cm x 39 cm)

10 System Architecture (Internal) 16” (40 cm) 10” (25 cm) 15” (39 cm)

11 Mass Analysis 2 Autoclaves 1890g 4 TECs 720g 2 Pumps 127g Water Chamber 132g Insulation 9.83g 2 Valves 1450g Tubing 396g 2 Reaction Chambers 173g Environmental Chamber 656g 2 Mixers 95.8g Chassis 1150g CPU and DAq (not shown) 292g Sensors (not shown) 10.0g Internal Mass: 7.10kg (15 lbs) Total Mass: kg (30 lbs)

12 2 weeks + 27 to 75 hr 25.5 hr 27 hr1.5 hr 3 hr Experiment Timeline Soil Start Finish Soil t=0Insert sample manually ___A B___ Heater A:Heater B: Cooler A:Cooler B: Cycle A: Cycle B: t1t1 S-- t2t2 --S t3t s t4t4 F*-- t5t5 **F* 49.5 hr 51 hr 73.5 hr 75 hr Autoclavet 6,7,8,9 **optional Can repeat two more times t6t6 Reaction ___A B___ Heater A:Heater B: Cooler A:Cooler B: Soil AB

13 Electrical Overview KEY

14 Autoclave Prototype Concerns: –Low power heating –Seals 304 Stainless Steel Height = 2.25 in. Inner Diameter = 1.5 in LabView External temperature sensor Internal pressure sensor

15 Prototype Thermal Analysis Steady state 2W energy loss Heater on flat area Large thermal gradient

16 Autoclave Prototype Results Results: –121 C for small 12W strip heater, higher pressure than expected –Very uneven heating –Seals held Conclusions: − 3 smaller strip heaters evenly spaced −TEC used only for cooling −O-ring seals were effective −Melamine insulation was effective

17 Mixing Prototype Ultrasonic –Frequency function of tip length –18 kHz not feasible Magnetic –May disrupt electrochemical sensors Pending tests by Tufts Mechanical –No off-the-shelf impeller options –Custom impeller designed

18 Mixing Prototype Results Results: Too much slip with impeller to use motor –Had to rotate impeller manually Sample developed air bubbles Flour-like consistency  very slow settling time Sediment remains on bottom of chamber Conclusions: Fluid movement around sides easily maintained Need cross-bar near the bottom Can maintain colloidal solution for several minutes without continuous mixing with 10-micron grains

19 Sample Transport Prototype Results Results: ¾” tubing did not transport sample 30% soil transported when dry 95% soil transported when wet Autoclaving did not affect soil consistency Conclusions: 1” tubing Water added to move sample

20 Autoclave Drawings 316 stainless steel Height = 2 in. with flat sides = 1.6 in. x 1.6 in. Wall thickness = in. Inner Diameter = 1.5 in. tapered Bottom View Valve Interface Lid Body O-ring Sensor Ports 1” diameter

21 Reaction Chamber Drawing Reaction Chamber with Mixer and Cap Ultem 1000 Height = 5.2 in. (13.19 cm) Diameter = 1.6 in. (3.95 cm) Wall thickness = in. (0.5 cm) Soil transport pathway = 1.0 in. (2.5 cm) Cap to support mixing shaft 20 sensor ports –12 electrochemical sensors –7 multi use ports –1 temperature sensor Motor Impeller Cap Sensor ports

22 Autoclave Stress Analysis Autoclave technique: –121 C with steam to aid heat flow –15 psi above atmosphere for saturated steam at 121 C Thin wall pressure formulas: –Minimum thickness = in. while actual used = in. –Critical pressure for in. is 20 kpsi Seals: –Regular threads alone will not seal –O-ring compression seals made of silicone for high temperature and pressure Conclusions: –O-ring seals are effective –Temperature of chamber is regulated and heater has limited heating power –Pressure relief valve added to port on lid

23 Electrical System Power supply is 12V Power conditioning is added to give cleaner power 5V power will be used to run sensors because of voltage stability Power supply AC-DC converterVoltage regulator

24 Sensors and Control Sensors will run constantly Switchboard controls power to: –TECs, mixers and LEDs The DAQ card can proportionally control: –Pumps, TECs and mixers

25 Software Timeline Start 0 Insert sample 30 s Autoclave A Turn on Autoclave control 1.User turns on program 2.Autoclave A begins heating 3.At 121˚C Autoclave A holds for 15 min 4.Autoclave A begins cooling and Autoclave B begins heating 5.Autoclave A finishes cooling 6.Autoclave B finishes cooling 7.Program notifies user autoclave has completed 1.5 hr Autoclave B Heating complete 27 hr Done 2 weeks + 27 to 75 hr Finish Done Water pump A & B Turn Valve Reaction Chamber Pumping complete Reaction control 1.User turns valves open and beings program 2.Turn on pumps for 25 sec (at 1mL/sec flow rate) 3.Turn on Reaction Chamber control

26 Assembly Flow Diagram Chassis Autoclave chambers (x2) Body Assembly Body Pressure Seal Insulation Strip Heater Cap Assembly Cap Temp & Pressure Sensors TEC Assembly TEC Heat Sink Reaction Chamber Envir. Reaction chamber (x2) Body Assembly Body ISE Package Mixer Assembly Motor Bearing Gears Impeller Body Assembly Body Insulation Temp & Pressure Sensors TEC Assembly TEC Heat Sink Reagent H2O Chamber Body Assembly Body Insulation Strip Heater Temp & Pressure Sensors DAQ Embedded CPU Interface Temp. & pressure Sensors ISE Package Power supply Power Supply Interface Sensors Temp & Pressure ISE Package Thermal Control TECs Strip Heater DAQ Peristaltic Pump Make Buy

27 Functional Test Plan Autoclave Reaction Chamber TEC Strip Heater Thermal Control Thermal Control TEC Sample Transport Mixing Motor Butterfly Valve Sample Consistency Heat from -10°C to 121°C Hold for 15 min Cool to 20°C Repeat 3 times Transport 90% of sample when reagent water pumped through Impeller Maintain temperature between 4°C and 37°C Maintain fluid movement around sides; Maintain minimal sedimentation on sides and bottom of chamber DAQ & Control Collection & Storage Command Interface Software Collect & store data from each sensor Receive commands from SW Provide caution, warning, status signals

28 Verification and Test Plan Reaction Chambers Autoclaves Reagent H 2 O Chamber Sample Transport Temperature Pressure Mixing Temperature Pressure Containment Delivery Sterilized sample Inoculation 4°C – 37°C 1 psi differential Small sedimentation, fluid sensors Thermistor in environmental chamber Pressure sensor in environmental chamber Visual/Video verification ≥121°C ≥15 psi Thermistor inside autoclave chamber through cap Pressure sensor inside autoclave chamber through cap Solid & liquid form ≤50mL (±5% accuracy) Thermistor inside autoclave chamber through cap < 60°C Time-based flow rate in peristaltic pump (controlled flow) Thermistor inside water chamber Aseptic deliverySterile swabbing of wet surfaces, culture test Data Acquisition & Control Collection & Storage Caution, Warning, Status Collected & stored for entire experiment Provide status, caution & warning signals DAQ storage capability analysis Testing LabView command software with set max temperature and shut-off abilities Power Nominal Consumption Peak Consumption ≤ 30W ≤ 30W for ≤ 30 sec Power model for all parts, measurement through multimeter in circuit Petri dish testing with bacteria and medium (BioServe)Sample sterilityNo microbial life in sample

29 Risk Assessment Probability Severity Low Medium High MediumHigh Sample transport Autoclave Mixing Water transport DAQ Reaction Chamber Thermal Control Budget Machining Time

30 Work Breakdown Structure MiDAs Project Management Project Manager Elizabeth Newton Assistant Project Manager Ted Schumacher Fabrication Lead Fabrication Engineer Dave Miller Assistant Fabrication Engineer Sameera Wijesinghe Assistance as Needed from Team Design Document Design Engineer Chuck Vaughan Design Engineer Jeff Childers Assistance as Needed from Team Verification and Testing Systems Engineer Shayla Stewart Software Engineer Steven To Assistance as Needed from Team

31 Schedule

32 Overall Budget ITEMPART NUMBERQUANTITYPRICE ($) THERMAL CONTROL Insulation (Melamine)86145K271 (24"x48"x2") $ Strip HeaterHK5544R33.1L12B7 $ Thermoelectric Cooler (TEC)CP L4 $ Heat SinkHX6-201-L-M4 $ SENSORS TemperatureSA1-RTD6 $ PressurePX1394 $ ISE Package (18/pkg.) -2 $ MECHANICAL Ultem K811 (24”X2” rod)$ Stainless steel89325K6732 (12”X2.5” rod)$ Aluminum89015K532 (48”X48”X0.0625”)$ Bearing6384K441 $ 7.41 Rotary-Shaft 1/4" Ring Seal9562K411 $ 3.15 PumpsP625/ $ Motors12242 $ Butterfly Valve4820K312 $ COMPUTER/DAQ DAQDMM-37X-AX2 $ Embeded CPUMOPSlcdLX1 $ Mixer ControllerPA75CC2 $ Thermoelectric ControllerWTC32434 $ TOTAL $

33 Resources and Facilities BioServe Laboratories –Matching funds –Spare/small parts –Machine shop –Temperature-controlled testing environment –Wet/Biological lab –Clean room Aerospace Department –Machine Shop –Electronics Shop

34 Conclusions Project feasible Team has necessary expertise, time and resources Risk mitigated through prototyping Can increase overall TRL

35 References 1.Cengel, Yunus. Introduction to Thermodynamics and Heat Transfer. McGraw-Hill. University of Nevada, Reno Gilmore, David. Spacecraft Thermal Control Handbook. Aerospace press. El Segundo, California Mankins, John C. “Technology Readiness Levels.” April 6,

36 Presentation Appendix 1.Title PageTitle Page 2.Briefing OverviewBriefing Overview 3.ObjectivesObjectives 4.TRL ObjectiveTRL Objective 5.DeliverablesDeliverables 6.Requirements OverviewRequirements Overview 7.Requirement RefinementRequirement Refinement 8.Mars/Earth ComparisonMars/Earth Comparison 9.System Architecture (External)System Architecture (External) 10.System Architecture (Internal)System Architecture (Internal) 11.Mass AnalysisMass Analysis 12.Experiment TimelineExperiment Timeline 13.Electrical OverviewElectrical Overview 14.Autoclave PrototypeAutoclave Prototype 15.Prototype Thermal AnalysisPrototype Thermal Analysis 16.Autoclave Prototype ResultsAutoclave Prototype Results 17.Mixing PrototypeMixing Prototype 18.Mixing Prototype ResultsMixing Prototype Results 19. Sample Transport Prototype ResultsSample Transport Prototype Results 20. Autoclave DrawingsAutoclave Drawings 21. Reaction Chamber DrawingsReaction Chamber Drawings 22. Autoclave Stress AnalysisAutoclave Stress Analysis 23. Electrical SystemElectrical System 24. Sensors and ControlSensors and Control 25. Software TimelineSoftware Timeline 26. Assembly Flow DiagramAssembly Flow Diagram 27. Functional Test PlanFunctional Test Plan 28. Verification and Test PlanVerification and Test Plan 29. Risk AssessmentRisk Assessment 30. Work Breakdown StructureWork Breakdown Structure 31. ScheduleSchedule 32. Overall BudgetOverall Budget 33. Resources and FacilitiesResources and Facilities 34. ConclusionsConclusions 35. ReferencesReferences

37 Drawing Tree

38 Drawing Tree (continued)

Mechanical Drawing Tree

40 Autoclave Body

41 Autoclave Cap

42 Autoclave Bottom

43 Thermoelectric Cooler (TEC)

44 Heat Sink

45 Reaction Chamber

46 Reaction Chamber Cap

47 DC Motor

48 Impeller

49 Reaction Chamber Environment

50 Reaction Chamber Environment Side Door

51 Peristaltic Pump

52 Pump Mount

53 PharMed Tubing

54 DAq

55 Embedded CPU

56 Chassis

57 Chassis Top

58 Chassis Front Interface

59 Electrical Schematic Tree

60 Electrical Schematic

61 Power System

62 Sensor Schematics

63 Sensor Wire Harness

64 Control Schematics

65 Control Schematics continued

66 Control Wire Harness

67 Switch board

68 DAq Block Diagram

69 Embedded CPU

70 Software tree AIn = Analog Input: Acquires pressure and temperature data DBit Out = Digital Bit Out: toggles output high or low to control the switch board Err Msg = Error message: displays error message if output is not configured right To Eng = Converts binary inputs from levels to voltage level ToEngArray= Converts array of binary inputs to voltage level = Autoclave temperature/pressure.vi = Elapse Timer: Counts amount of time elapsed after specific case = Time Delay: Waits specified time before taking next sensor data = Write File: Writes data to measurement file

71 Software Prototype