Objectives Overview

• Objective: Create an Earth field unit to test electrochemical sensors

• Deliverables:– Field-ready unit– Test data verifying requirements– Operational manual for use– Document proposing design solutions to

make the instrument more Mars-ready• Mars-applicable solutions do NOT have to be

implemented on field unit

Requirements Overview

• Changes to PDD requirements:– Requirement 4.24 removed: MiDAs must no longer provide

its own power– Will still be able to accept power from various sources– Power supply options will be included in design document

• Project Focus Change: – Complete autonomy no longer crucial component

• Increased reliance on experimenter to open valves and deliver inoculation sample

• Change at request of customer – tradeoff of autonomy versus reliability in field instrument

• Autonomy deemed out of the scope of this project• Autonomy options will be included in design document

– Autonomous data collection and storage, heating, cooling, and mixing still part of design

System Architecture

Chambers

Reaction Chambers

Reagent Water Chamber

Autoclave Chambers and Cap

Subsystem Breakdown

ChassisEnvironmental Chamber

Pump and Mount

Electrical Block Diagram

Reagent Water Chamber

Autoclave 1 Autoclave 2

Control Chamber Test Chamber

Data Acquisition/Control

Electrochemical Sensors(18)

Water Pump

Test Chamber Environment

V1

V2

IHCTemp control

Dig.Out: Digital Output

ET: Environmental Temperature Sensor

IHC: Incubator Heater/Cooler

L1: Light 1

L2:light 2

M1: Mixer 1

M2: Mixer 2RT: Reagent Water Temperature SensorSG1: Soil Transportation Gate 1SG2: Soil Transportation Gate 2TT: Test Chamber Temperature SensorTP: Test Chamber Pressure SensorV1: Water Valve 1V2: Water Valve 2

Speed control M1 Speed controlM2

SG2SG1

Control Switch

AT AP

CP

AHC1 AHC2

CT

TP

ET

TT

RT

AT1

AP1AP2 AP2

Power SourcePower

Conditioning/Protection

Power Distribution/Switching

AHC2: Autoclave heater/cooler 2AHC1: Autoclave heater/cooler 1An.In: Analog inputAn.out: Analog outputAP: Ambient Pressure SensorAT: Ambient Temperature SensorAP2: Autoclave Pressure Sensor2AT2: Autoclave Temperature Sensor2CP: Control Chamber Pressure SensorCT: Control Chamber Temperature Sensor

Temp control/Power Cut off

TempControl/

Power cut off

Dig.Out

An.In

An.out

CPU Communication (USB)12VAC/

12VDC

12V 12V

L2L1

Experiment Timelinemin Description Measurement Test yes/no Control heat cool

t = 0 begin autoclave cycle again

  Is t = 317? yes   off off increment time, move to next step

        no   ----- ----- continue autoclave cycle

t = 318 begin autoclave cycle again

  Is t = 635? yes   off off increment time, move to next step

        no   ----- ----- continue autoclave cycle

t = 636 begin autoclave cycle again

  Is t = 953? yes   off off increment time, move to next step

        no   ----- ----- continue autoclave cycle

t = 954 Autoclaving complete visual Are heater and cooler off? yes open auto clave ejection valve and water valve

    perform next test

        no Stop, check for failure     stop

  Heater is off Cooler is off

  Are valves open? yes pump 25mL water through autoclave

    increment time, move to next step

  begin soil transportation

    no Stop, check for failure     stop

t = 955 finish soil transportation

temperature Is pump done? yes close valves, begin taking measurements, zero electrochemical sensors

    perform next test

  initialize sensors pressure   no --------------     increment time, repeat

  inoculate Electro-chemical Is data being recorded/electro-chemical zeroed? 

yes inoculate     increment time, move to next step

        no Stop, check for failure     stop

t = 956 begin mixing temperature Is test chamber inoculated? yes turn on mixers     perform next test

  temperature control pressure   no stop, check experiment for failure     stop

    Electro-chemical Is temperature <= 6°C? yes -------------- on off perform next test

        no -------------- off off perform next test

      Is temperature >=35°C? yes -------------- off on increment time, repeat until t = 21116

        no -------------- off off increment time, repeat until t = 21116

Thermal Analysis

total

gssurroundininside

R

TTQ

tQ

Q hrst

hrst

cool

heat

3.1

8.2

soilpwaterpsteelp TmcTmcTmcQ

Mass Analysis

• Peristaltic Pump & Motor = 106g• Shared Environment = 646g• Reaction Chambers =173g• Water Chamber = 132g• Autoclaves = 263g• Insulation = 20.5g• Chassis = 1.150 kg• Sensors = 10.0g• Valves = 454g

• Total = 2.95Kg

Power Summary

Power Summary (Experiment)

0

5

10

15

20

25

012

024

036

048

060

072

084

096

010

8012

0013

2014

4015

6016

8018

0019

20

Operation Time (min)

Po

wer

Co

nsu

mp

tio

n (

W)

Thermal

Structures

Electronics

Total

Autoclave Power Summary

Power Summary (Sterilization Phase)

0

5

10

15

20

25

30

012

024

036

048

060

072

084

096

010

8012

00

Operation Time (min)

Po

wer

Co

nsu

mp

tio

n (

W)

Autoclave Heater/Cooler 1

Autoclave Heater/Cooler 2

DAq

Temp/Pressure Sensors

Total Power