preliminary design review october 21, 2014 project manager: gabrielle massone deputy project manager...

1

Preliminary Design ReviewOctober 21, 2014

Project Manager:Gabrielle Massone

Deputy Project Manager Financial LeadTanya Hardon

Optics Lead:Jon Stewart

Mechanical LeadJake Broadway

Electrical Lead:Logan Smith

Systems Engineer:Jesse Ellison

Software Lead:Cy Parker

Test and Safety Lead:Franklin Hinckley

Thermal Lead:Brenden Hogan

Customers:Brian Sanders Colorado Space Grant (COSGC)

JB Young and Keith MorrisLockheed Martin (LMCO)

Faculty Advisor:Dr. Xinlin LiDept. Aerospace EngineeringLaboratory for Atmospheric and Space Physics (LASP)

Overview Baseline Design Optics Thermal Electrical Testing Logistics

2

Presentation Overview Mission Overview Baseline Design Feasibility Analysis

• Optics and Mechanical Design• Thermal Design• Electrical and Software Design

Testing Plan and Feasibility Design Summary Logistics


3

PROJECT OVERVIEW


4

Mission BackgroundLockheed Martin 6U CubeSat Bus Design Reference Mission

to Asteroid 101995-Bennu


5

Mission BackgroundLockheed Martin 6U CubeSat Bus Design Reference Mission

to Asteroid 101995-Bennu


Relevant IR Camera Payload Operations that Drive Phoenix ConOps

6

Mission Background LMCO Bus IR Camera Payload will capture sequence

of images of Bennu asteroid and measure the observed angular rate

3.5 µm wavelength in Mid-Wave Infrared (MWIR) Range and geometry specified below:


Bennu Asteroid (Reference Environment)

IR Camera

Bennu

FOV

Distance: 10 km

ω = 0.4061 mrad/s Observed:θ = 21.93 µrad/s

D = 492 m

Tamb = 3KTsur = 180-310Kε = 0.035

7

Mission Background Utilize MWIR nBn detector (Lockheed Martin Santa

Barbara Focalplane)• Operating Temperature: 140 K• Resolution: 1.3 MPx or 1280x1024

First MWIR detector Feasible for CubeSat Operations


Reduced Dark Current, Operating Temp. of 140+ K vs 77 K (Traditional)

InAs N-doped Semiconductor Layers Sandwiching 100 nm AlAsSb Barrier

Figures courtesy of: Applied Physics Letters, October 9, 2006 - 151109

8

Mission Background

1.3 MPx (1280x1024) nBn detector Image


Figure courtesy of: laserfocusworld.com January 17, 2014

9

Phoenix Objectives

Proto-flight Unit: Defined as hardware that is designed to flight form-factor, but may require additional design, development, testing or flight certification.

Not required to undergo environmental testing (thermal-vacuum cycling, vibe, radiation testing, etc…) and will not be flown.

To develop and test the 2U CubeSat MWIR Camera Proto-Flight Payload, a precursor to the flight

camera unit for the LMCO Bus Mission


10

Phoenix Objectives


Req. Description Parent

O.1 The payload shall integrate electrically and structurally into the 2U payload section of the Lockheed Martin 6U CubeSat bus MS

1.SYS.1 The electrical system shall interface with the LMCO 6U CubeSat bus O.1

1.SYS.2 The mechanical system shall interface with the LMCO 6U CubeSat bus O.1

1.SYS.3 The Software system shall interface with the LMCO 6U CubeSat bus O.1

O.2The payload shall capture a sequence of IR images at the 3.5 µm wavelength and determine the angular velocity and axis of rotation of an observed object with characteristics of the reference asteroid 101995-Bennu

MS

2.SYS.1 The electrical system shall capture and store an image from the image sensor. O.2

2.SYS.2 The optical system shall be able to observe and image the reference target O.2

O.3 The payload shall maintain all components in their operating temperature ranges. MS

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CubeSat Bus Design Constraints

Bus Electrical Constraints

Regulated Voltage Lines3.3 V 6.0 A Max

12 V 4.0 A Max

Unregulated Voltage 6.5 V – 8.6 V 6.0 A Max

Total Power 5 W Nominal Average15 W Peak

Command Communication Bus SPI Slave

High-Speed Communication Bus Ethernet, Magnetics-Less Differential

Backup Communication Bus I2C

Bus Structural Constraints

Total Volume 2U (10x10x20 cm)

Total Mass 2.66 kg + 0.1 kg/ - 0.5 kg


12

Timeline and Assumptions

Phase 1: Simplifying Assumptions Simulated range between Phoenix and target will vary

between 10 km and 100 km Zero Relative translational velocity between object and bus

during observation (Phase 2 unit software will account for relative motion)

Phoenix payload is not exposed to direct sunlight (i.e. bus orientation or deployables shade payload volume)

All test target properties are representative of asteroid 101955-Bennu to the extent feasible


Phase 1

May 2015Oct 21

Prototype of all subsystemsFirst integration and ground-

testing

Flight RevisionContinue Remaining

Development

Senior Design Potential Post-Senior Design Development

DeliveryFully-tested,

flight certified

Phase 2

Milestones

13

Phoenix ConOps


Instantaneous observed angular rate of the nearest point is the arctangent of the translational velocity of the surface divided by the observation distance

d

Phoenix is measuring the observed angular rate (theta), not the rotation rate of the object

(omega)

14

Phoenix ConOps Culmination of design is fully-integrated

ground-test of sensor and representative target object


15

BASELINE DESIGN


16

Design Overview

RadiatorPanels

Bus Mechanical Interface

Power BoardCDH Board

Thermal StrapSensor Board

Primary Mirror

Secondary Mirror

2U CubeSat Payload10cmx10cmx20cm


10 C

m10 Cm20 Cm

17

Functional Block Diagram


Structure and Optics Focusing Assembly

Structure

Thermal Control Mechanism

Opti

cs A

ssem

bly

* LM

CO 6

U C

ubeS

at B

us

ElectronicsBu

s Th

erm

al Is

olati

on *Sensor Interface(COSGC)

Field of View

Phoenix Camera Payload

*COTS or Customer-Provided

*Image Sensor (LMCO)

Camera Controller• Main Processor• Image Processing

and Compression Software

Thermal Controller

Power Regulation

Bu

s Po

wer

and

Dat

a In

terf

ace

PWR

PWR

PWR Thermal Feedback

Image Data, Sensor Control

PWRPWR

Post-Processed Image Data

Power

Bus Power Supply

Data

18

Critical Project Elements Mechanical Optics Assembly Design Thermal System Design

• Cooling the nBn sensor Electronics and Software System

• Interfacing with nBn sensor• Measuring Rate from Image Sequence

Testing Plan• Ground testing to simulate flight functionality


19

OPTICS AND STRUCTURE


20

Bennu Radiometry Percentage of total light in 3 to 4 µm band due to

• Solar irradiance (~12-15%)• Bennu blackbody radiation (~85-88%)

Photon Budget:


Total Photon FluxPhoton Flux (photon/s)

Range (km)

Cassegrain Optics

Refractive Optics

40 60 80 100

3x1013

2x1013

1x1013

21

Bennu Radiometry


22

Baseline Optical Design CDD baseline designs:

• Multi-element refractive & Cassegrain optical systems

MWIR bandwidth is diffraction limited


Source: http://microscopy.berkeley.edu/courses/tlm/optics/imaging.html

Diffraction Limit Illustration

Resolvable Airy Disk Resolvable Airy Disk

Unresolvable Airy Disk Unresolvable Airy Disk

Airy Disk

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Baseline Optical Design Chief deciding factors: Mass, Thermal Control, Size, etc…


Cassegrain selected for Optical Design

RefractiveMass ~ 1.8 kgActive Thermal CoolingChromatic AberrationsLength ~ 12.5 cmHigh Design ComplexityBandwidth: 3.0 – 3.74 µm

CassegrainMass ~ 1.0 kgPassive Thermal CoolingNo Chromatic AberrationsLength ~ 10 cmBandwidth: 3.0 to 3.61 µm

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Zemax Simulation Utilized paraxial ray tracing equations to

derive design constraints Zemax simulation to prove design

methodology

• • •


Spot Diagram

FPA

Primary Mirror

Secondary Mirror

Cassegrain Simulation

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Mechanical BudgetSubsystem Mass (g)

Structures 328

Optics 81

Electronics 59

Thermal Control 157

Total 625

Allowable Mass 2000

Contingency 1375


Structure 16.4%

Optics 4.1%Electronics

2.9%

Thermal Control 7.8%Margin

68.75%

Mass Distribution Large Mass Contingency Values from Solidworks

Model Estimates

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Path Forward Design aspherical lenses to reduce

aberrations and add bandpass filter Make Zemax program to optimize system

PSF and minimize ΔT impacts on system Design cold stop to reduce background

thermal noise Thorough calculation of SNR and SBR with

respect to all noise inducing elements Call prospective suppliers to check for issues

with budget and feasibility constraints


27

THERMAL

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Current Thermal Concept Bus will shield the payload from

solar rays Bus interface within -24 to 61 ºC

• Interface will be isolated using low conductance bolts and/or structural elements

• MLI insulation between bus and payload

Aluminum radiators coated in high-emissivity white paint on all payload sides

TEC to reduce focal plane temperature to ~140K• From manufactures

specification


6U Bus Conceptual Configuration

2U Phoenix Camera Volume

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Thermal Electric Cooler (TEC) Operates using the Peltier Effect

• P and N type semiconductors physically in parallel but electrically in series

• Draws heat from one side to the other Can be stacked to produce additional cooling Two Stage Baseline Model

• ~1W of consumed power• Max heat in: 0.3W• Delta Tmax: 92 K

• Small Size• 3.9mm x 3.9mm x 4.4mm

• Long operating life• <100,000 hrs

Source: https://www.ferrotec.com/images/thermal-site/twoStage.png


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Primary Thermal Paths

Bus Interface T = -21 to 64 ºC

Qbus


QSun

Aluminum Radiator 700cm2 (White Paint Coating α=0.09 ε=0.92)

QRadiated

Qalbedo

Opti

cs A

ssem

bly

TEC

Wbus

nBn Focal Plane

Command and Data Handling (CDH) Board

Electrical Power and Bus Interface Board

Thermal Isolation

QRadiated

Bus Solar S

hadeBus Solar Shade

Phoenix Payload

KeyRadiation

Conduction

High Resistance

Low Resistance

Electric Work

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Thermal Modeling StrategyGoal: Full System Thermal Model using

Thermal Desktop Software Fall 2014:

• Develop basic thermal models comparing ~10-25 nodes in both Simulink and Thermal Desktop

Post-CDR: • Continue Thermal Modeling with Thermal Desktop• Goal: model agrees to within ± 5 K of actual

hardware temperatures (AFRL Standard) Driving Issue:

• Thermal Desktop results are complex - it can be difficult to identify errors in basic model

Solution:• Develop two independent models• Verify results of Thermal Desktop model before

moving forwardOverview Baseline Design Optics Thermal Electrical Testing Logistics

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Thermal Desktop Model (Steady State)

Aluminum Radiators with White Paint Coating

Bus-Payload Mechanical Interface• ~10W

CDH Board• ~0.3W

EPS Board (Not-Pictured, behind CDH board)• ~0.7W

Not currently in model• Thermal Electric Cooler

• ~1W• nBn Focal Plane

• ~0.3W• Optics Assembly

Bus Simulator• Modeled as

10W constant heat source

Hottest part of the payload is the bus interface

CDH Board

EPS Board

EPS Board

Cold Space ~3K

• Green Arrows-Conduction to parts contacting that face• Brown Arrows-Conduction receiving nodes from other parts contacting that face• Red Arrows-Heat loads on that surface• Balls-Nodes of the model


33

Simulink Thermal Model


Major components modeled as Simulink subsystems with heat inputs and outputs

Subsystem blocks contain models of thermal resistivities and conductivities

34

Feasibility Analysis (Simulink)

Radiator

Area 700 cm2

Emissivity 0.92

Material Aluminum

Thermal Conductivities

Aluminum 237 W/(m*K)

PCB (FR4/Copper) 0.33 W/(m*K)

Glass (Optical Lenses) 1.05 W/(m*K)

Bus Inputs

Max Qin 10 W

Qin to Electronics 7 W (30%)

Qin to Optical Assembly 3 W (70%)

Qin to TEC/Focalplane 0 W (negligible)

Asteroid Inputs

Max Qin 1.56 μW

Qin to Focalplane 0.312 μW (20%)

Qin to Optical Assembly 1.248 μW (80%)

Qin to TEC/Focalplane 0 W (negligible)Other Properties

Glass Emissivity 0.93

Time to Steady State 10,000 seconds

Simulink Simulation Assumptions & Parameters:


35

Feasibility Analysis

Using the worst case power inputs, the steady state temperature is low enough for the TEC to cool the focal plane to 143K (ΔT ~92K). While this is higher than the optimal 140K, the noise induced by the higher temperature could be processed out.

Additionally the optical assembly does not need to be cooled

Simulation Inputs

Heat from Bus into Sys. 10 W

Heat from Asteroid 1.5 μW

Power into Focalplane 0.3 W

Power into Electronics 1.0 W

Power into TEC 1.0 W

Total Energy into Sys. 12.3 W

Simulation Outputs

Heat out of Radiator 11.2 W

Heat out of Optics 3.0 W

Heat out of TEC 2.4 W

Heat out of Electronics 7.3 W

Heat out of Focalplane 0.8 W

Steady State Tradiator 235.4 K


36

Feasibility Analysis

The steady state temperature drops by 5K, reducing the necessary ΔT to 90K. This shows that with a 10% reduction in heat from the bus the TEC can cool the focal plane to the desired temperature.

Simulation Inputs

Heat from Bus into Sys. 9.0 W

Heat from Asteroid 1.5 μW

Power into Focalplane 0.3 W

Power into Electronics 1.0 W

Power into TEC 0.3 W

Total Energy into Sys. 10.6 W

Simulation Outputs

Heat out of Radiator 10.2 W

Heat out of Optics 2.70 W

Heat out of TEC 2.24 W

Heat out of Electronics 6.6 W

Heat out of Focalplane 0.69 W

Steady State Tradiator 230.0 K


Considering a case where the payload receives less heat from the bus (the bus is in a power saving mode, and less subsystems are

turned on, therefore less heat is generated)

37

Path Forward Continue adding payload elements to the

Thermal Desktop Model Update the Simulink Model material properties

as materials are chosen Compare the results of the two models to

verify consistency and accuracy Use Thermal Desktop Model for final thermal

analysis Extra volume available if additional active

thermal control required • Linear Stirling Cooler or multiple TECs

Exploring Thermal Isolation mechanisms• MLI, high thermal-resistance materials


38

ELECTRICAL AND SOFTWARE


39

Electronics Overview


nBn Image Sensor

Image Sensor Backplane

Command and Data Handling

Power Regulation

Raw Image Data

Power

• Small Adapter Board for nBn Mid-Wave IR Sensor

• Low Thermal Resistance Substrate

• Processes Images and Commands• High-Density Multi-Layer Board

• Provides power regulation and isolation from the bus

• Primary bus interface

Baseline Design: Custom PCB Stackup

40

Electronics



Power Regulation & Isolation

Bus Interface

Power Regulation

IsolationThermal Electric Cooler

Switching

Monitoring &

Protection Circuitry

Image Sensor

Interface

Memory

CPU nBn Sensor

TEC


41

Power Budget

Design Element Reference Component Nominal Power Consumption

TEC Laird MS2 series 1.0 W

CPU Atmel SAMA5D4 series 0.20 W

Image Sensor Interface Xilinx Spartan3 series 0.16 W

Focal Plane nBn-sensor 0.05 W

Memory Micron SDRAM 0.39 W

Power Regulation Buck/Boost 90% efficient 0.80 W

TEC Control Buck 90% efficient 0.10 W

Raw Total No Margin 2.7 W

System Margin 20% 0.54 W

Total + Margin 3.2 W

Contingency 1.8 W

Budget 5W nominal, 15W 10 minute burst


42

Software Flow DiagramStandby Mode Active Mode

Initialize

Wait for Command

Package Data

Send Data to Bus

Command?

Picture Command

Report Health and Status

Get Focalplane Temp

nBn Cool?

Take Picture Burst

Picture Cmd Type

Compress Image and Package

Send Image to Bus

Determine Rate

No

Yes


Rate Determination Algorithm

(Cont. Next Slide)

43

Software Flow Diagram

Harris Corner Detection• Interest point

identifier• Invariant to

translations and rotations

SIFT• Used to classify each

interest point and keep only those robust to local affine distortion

Rate Determination Algorithm

Noise Reduction (Optional)

Harris Corner Detection & SIFT Keypoint Descriptors

Repeat for 2+ Image Sequence


Match SIFT Keypoints

Calculate Rate Solution

Send Solution to Bus

44

Examples HarrisSIFT Algorithm

• Interest Point Detection and Matching• Image Rotated 180º


Figure generated using Integrated Vision Toolkit and HarrisSIFT Algorithm

45

Temporal Budget Maximum allowable exposure time 2.28

seconds• Bennu rotation rate + 1σ = ~22μradians/second• Rotation of 50 μradians corresponds to a single

pixel• Corresponds to minimum spacing of images

Maximum image capture spacing• Case of rotation gives about 9 hours

• Will use as baseline limit


T = 9 Hrs

Surface Feature

T = 0 Hrs

46

Path Forward Determine data rates and create data

budget Select Processor and Electrical Components Begin Electrical Schematics Select Software Platform

• Operating System (i.e. Linux)• Bare Metal

Software Algorithm development

47

TESTING FEASIBILITY


48

Preliminary Testing Plan

Setup and Procedure Test Chamber contains

• Phoenix Camera and Test Target• Optics Adapter• MGSE structure• EGSE conduits

Phoenix captures MWIR images, determines observed angular rate

Compare theoretical and actual angular rate

Test Equipment Vacuum chamber capable of < 1

torr (procurable) Liquid Nitrogen cooled to 75K

(procurable)• Radiative heat transfer error 5% at

Tsurr = 108.9 K

• 0.632 L/min circulation rate for∆T = 5K

• 16.6 mL/min vaporization rate EGSE and MGSE


49

Environmental Control

Phoenix Camera and test hardware mounted to sled

LN2 cooling jacket maintains ~75 K wall temperature

12.5” fiberglassinsulation (two layers of R19 batt) to reduce LN2 loss


Cross Section of Test Chamber, with minimum required dimensions

12.5”

50

Test Target and Scaling

Test Target Objective: To replicate the scale, motion, and spectral qualities of reference asteroid 101995-Bennu Hollow Sphere, 10 cm diameter Internal heating elements heat to 310 K (illuminated side)

and 180 K (dark side)• Heater wires through slip-ring to allow target rotation

Optics Adapter (Zoom 0.300X)• Scaled distance: 203 cm• Actual distance: 61 cm

Parameter Value (Bennu) Value (Target)

Diameter 492 m 10 cm

Observation Distance 10 km 203 cm (effective)

Rotation Rate 0.4061 mrad/s 0.8904 mrad/s

Observed Angular Rate 21.93 µrad/s 21.93 µrad/s


51

Phoenix Scaled TestingBennu Asteroid (Reference Environment)

Phoenix (Scaled Ground Test)

Camera

Phoenix

Optics AdapterZoom: 0.300X

101995-Bennu

Actual Distance: 63 cm Effective Distance: 203 cm

FOV

FOV

Distance: 10 km

Test Target• Hollow Sphere• Heated

ω = 0.4061 mrad/s

ω = 0.8904 mrad/s

Observed:θ = 21.93 µrad/s

Observed:θ = 21.93 µrad/s

D = 10 cm

D = 492 m

Tamb = 3K

Tamb = 75 K

Tsur = 180-310Kε = 0.035

Tsur = 180-310Kε = ~0.035


52

Path Forward Explore testing opportunities and

capabilities at Space Operation Simulation Center (SOSC) at Lockheed Martin in Waterton

Confer with Matt Rhode for all LN2 Handling and Testing

Detail intermediate testing plans for system build-up

Determine required optical/thermal properties of test target to accuracy required for construction


53

DESIGN SUMMARY


54

Design Summary

nBn Image Sensor



Power Regulation

Raw Image Data

Power

2U MWIR Camera Volume, 700 cm2 Radiator Area

Two-Stage Thermoelectric Cooler Custom Electronics and Software

Cassegrain Reflector Optics


55

LOGISTICS


56

Fall ScheduleOctober November December

Major Milestones

10/13-10/19

10/20-10/26

10/27-11/02

11/03-11/09

11/10-11/16

11/17-11/23

11/24-11/30

12/01-12/07

12/08-12/14

12/15-12/21

12/22-12/28

12/29-01/05

PDR

Simulink Thermal Model

Thermal Desktop Model

Zemax Optics Model

Solidworks Model

Electrical Component Selection

Electrical Schematics

Electrical Layout

CDR

FFR


57

Monetary Budget


Component Cost Estimate

Optics (mirrors, lenses) $5,000

Electronics $1,500

Thermal $1,000

Mechanical $1,000

Test Equipment $1,000

Total $9,500

Margin 20% $1900

Total + Margin $11,400

Contingency $8600

Funds available to team: $20,000

58

Team Management Tools Redmine

• Project Management Web Application• Issue tracking system• Gantt Chart and Calendar

Configuration Management• Git version control• Central file storage – Odyssey servers• File and component naming schemes

SYS.###.Rev_FileDescriptorEx: STR101.2_MassBudget

Test/Requirements Verification Software


59

CONCLUDING STATEMENTS


60

Conclusions

Thank you for your time

Acknowledgements PAB Faculty and Staff Faculty Advisor

• Dr. Xinlin Li Our customers

• Brian Sanders (COSGC)• JB Young (LMCO)• Keith Morris (LMCO)


61

References[1] Adams, Arn. "ADVANCES IN DETECTORS: HOT IR Sensors Improve IR Camera Size, Weight, and Power." Laser Focus World. PennWell Corporation, 17 Jan. 2014. Web. 13 Sept. 2014.

[2] "An Introduction to the NBn Photodetector." UR Research. University of Rochester, 2011. Web. 12 Sept. 2014.

[3] "ARCTIC: A CubeSat Thermal Infrared Camera." TU Delft. Delft University of Technology, 2013. Web. 13 Sept. 2014.

[4] Cantella, Michael J. "Space Surveillance with Infrared Sensors." The Lincoln Laboratory Journal 1.1 (1989): n. pag.Lincoln Laboratory. MIT, June 2010. Web. 9 Sept. 2014.

[5] Cleve, Jeffrey V., and Doug Caldwel. "Kepler: A Search for Extraterrestrial Planets." Kepler Instrument Handbook (2009): n. pag. 15 July 2009. Web. 12 Sept. 2014.

[6] "James Webb Space Telescope - Integrated Science Instrument Module."ISIM. Space Telescope Science Institute, n.d. Web. 13 Sept. 2014.

[7] "NBn Technology." IR Cameras. IRC LLC, n.d. Web. 13 Sept. 2014.

[8] Nolan, M.C. et al, “Shape model and surface properties of the OSIRIS-Rex target Asteroid (101955) Bennu from radar and lightcurve observations,” Icarus, Vol. 226, Issue 1, 2013, pp. 663-670.

[9] Otake, Hisashi, Tatsuaki Okada, Ryu Funase, Hiroki Hihara, Ryoiki Kashikawa, Isamu Higashino, and Tetsuya Masuda. "Thermal-IR Imaging of a Near-Earth Asteroid." SPIE: International Society of Optics and Photonics. SPIE, 2014. Web. 13 Sept. 2014.

[10] "Spitzer Space Telescope Handbook." Spitzer Space Telescope Handbook 2.1 (2013): n. pag. Spitzer Space Center, 8 Mar. 2013. Web. 8 Sept. 2014.

[11] Vanbebber, Craig. "Lockheed Martin Licenses New Breakthrough Infrared Technology." Lockheed Martin Corporation, 7 Dec. 2010. Web. 9 Sept. 2014.

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BACKUP SLIDES

63

TRADE STUDIES BACKUP

64

Trade Study Scoring 10 Excellent, design best satisfies the criteria compared to

the other design options 8-9 Good, satisfies the criteria well 5-7 Mediocre, satisfies the criteria with some difficulty or

challenge 3-4 Poor, difficult to satisfy design criteria, presents technical

challenges 1-2 Very poor, presents significant challenge to satisfy

criteria

R = Raw Score W = Raw Score*Weight Total = Sum(W)

65

Optics Trade Study

Sensitivity Analysis

66

Thermal Trade Study


67

Electronics Trade Study


68

OPTICS BACKUP

69

Paraxial Ray Tracing Equations

Equation 2:

Equation 1:

http://ecee.colorado.edu/~ecen5616/WebMaterial/05%20paraxial%20ray%20tracing.pdf

70

Optics Design Equations Photon Budget:

• Planck’s Blackbody Radiation Equation

• Stefan-Boltzmann’s Law

Cassegrain Constraints:

𝐼𝑏𝑙𝑎𝑐𝑘𝑏𝑜𝑑𝑦=2 h𝑐2

𝜆5 ∗ 1

𝑒h𝑐𝜆 𝑘𝑇 − 1

𝑃𝑆𝐵=4𝜋 𝑅2𝜎𝑇 4

𝑅𝑝𝑟𝑖𝑚𝑎𝑟𝑦=−2∗𝑡𝑝𝑠∗𝐸𝐹𝐿𝐸𝐹𝐿−𝐵𝐹𝐷

𝑅𝑠𝑒𝑐𝑜𝑛𝑑𝑎𝑟𝑦=−2∗𝑡𝑝𝑠∗𝐵𝐹𝐷

𝐸𝐹𝐿−𝐵𝐹𝐷−𝑡𝑝𝑠

EFL – effective focal lengthBFD – back focal distancetps – mirror separation

71

Transmissive Design Cooke Triplet Constraints

Zemax Simulation

Φ𝑝𝑜𝑠𝑖𝑡𝑖𝑣𝑒=− −

(Φ¿¿𝑝𝑛𝑝 𝑣𝑝−2 Φ𝑣𝑎)+√ (Φ𝑝𝑛𝑝 𝑣𝑝−2 Φ 𝑣𝑎 )2− 4 (𝑣𝑎−𝑛𝑎𝑛𝑏𝑣𝑏)𝑣𝑎Φ2

2(𝑣𝑎−𝑛𝑎

𝑛𝑏

𝑣𝑏)¿

Φ𝑛𝑒𝑔𝑎𝑡𝑖𝑣𝑒=−(Φp −2 Φ𝑎

𝑛𝑎 )𝑛𝑏

Custom Gauss TripletCooke Triplet

72

Optical Thermal Analysis Used Stefan-Boltzmann equation to calculate

light passing through Cold Stop Signal to background ratio for 230° K optical system

Bennu

73

THERMAL BACKUP

74

Peltier Effect in TECThermoelectric coolers use the Peltier Effect to generate temperature gradient

Where is the Peltier coefficient of the conductor A, of the conductor B, and I is the electric current from A to B.

Peltier coefficients represent how much heat is carried per unit charge. If A and B are different, and a simple thermoelectric circuit is closed then the Seebeck effect will drive a current, which in turn will always transfer heat from the hot to the cold junction.

75

Simulink – Electronics Subsystem

Subsystem Specific Values:Electronic Board Area – 200cm^2Electronic Board Thickness – 0.173cm Radiation Coefficient of PCB – 4.82E-8 W/m^2*K^4Specific Heat of PCB – 810 J*K/kg

76

Simulink – Optical Subsystem

Subsystem Specific Values:Optical Assembly Area – 314cm^2Radiation Coefficient of Glass – 1.1E-9 W/m^2*K^4Specific Heat of Glass – 447 J*K/kg

77

Simulink – Focalplane Subsystem

Subsystem Specific Values:Focal Plane Area – 19.625cm^2

78

Simulink – TEC Subsystem Subsystem Specific Values:TEC Area – 15.21mm^2TEC Thickness – 4.4mm

79

Simulink – Radiator Subsystem Subsystem Specific Values:Radiator Area – 700cm^2Radiator Thickness – 5mmRadiation Coefficient – 5.21e-8 W/m^2K^4Radiator Mass – 0.25 kgSpecific Heat of Aluminum – 900 J*K/kg

80

ELECTRONICS BACKUP

81

Custom PCB Examples Previous designs by Phoenix team members

Communications Board: Xilinx Kintex 7 FPGA, high-speed DDR3 Memory

82

Custom PCB Examples

Attitude Determination and Control: SAMA5 ARM Processor and High-Speed Memory

preliminary design review october 21, 2014 project manager: gabrielle massone deputy project manager...

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