Manufacturing Status Review
February 3, 2015
Project Manager:
Gabrielle Massone
Systems Engineer:
Jesse Ellison
Deputy Project Manager
Financial Lead
Tanya Hardon
Software Lead:
Cy Parker
Optics Lead:
Jon Stewart
Mechanical Lead
Jake Broadway
JB Young and Keith Morris
Lockheed Martin (LMCO)
Test and Safety Lead:
Franklin Hinckley
Thermal Lead:
Brenden Hogan
Customers:
Brian Sanders
Colorado Space Grant (COSGC)
Faculty Advisor:
Dr. Xinlin Li
Dept. Aerospace Engineering
Laboratory for Atmospheric and
Space Physics (LASP)
Electrical Lead:
Logan Smith
Purpose and Objectives
Schedule
Manufacturing Status
Budget
1
Presentation Overview
 Project Purpose and Objectives
 Schedule
 Manufacturing Status
•
•
•
•
Optical and Mechanical
Thermal
Electronics and Software
Testing
 Budget
 Concluding Statements
Purpose and Objectives
Schedule
Manufacturing Status
Budget
2
PROJECT PURPOSE AND
OBJECTIVES
Purpose and Objectives
Schedule
Manufacturing Status
Budget
3
Phoenix Mission Objective
Develop a proto-flight, angular-velocity sensor payload that
can observe an object in mid-wave infrared and determine the
angular velocity of the object in the field of view
Proto-flight Unit:
Defined as hardware that is designed to flight form-factor, but will be tested
exclusively on the ground and is not required to undergo environmental testing.
Purpose and Objectives
Schedule
Manufacturing Status
Budget
4
Mission Concept
Example angular velocity sensor concept
ω
6U CubeSat with
Rate Sensor Payload
Observing asteroid in FOV
Characterize rotation of asteroid for
rendezvous operations
Bennu 101955
Asteroid
Video courtesy of www.asteroidmission.org
Purpose and Objectives
Schedule
Manufacturing Status
Budget
5
Mission Concept
Use this sequence of images to determine the object’s
angular velocity vector in the camera FOV
Report this observed rate to
the bus
Effectively an infrared
angular velocity sensor
Purpose and Objectives
Schedule
Manufacturing Status
Budget
6
Design Overview
Phoenix Interfaces with the 6U LMCO Bus
•
Inhabits 1/3 of spacecraft volume
Phoenix CPE’s:
1. Optics and Mid Wave IR
Imaging system
2. Thermal Control System
3. Supporting Electronics
4. Software Angular
Velocity Determination
Algorithm
10 cm
Purpose and Objectives
Schedule
Manufacturing Status
Budget
7
SCHEDULE
Purpose and Objectives
Schedule
Manufacturing Status
Budget
8
Critical Path
Optics:
•
•
Mirrors Complete: 3/15
Integrated by: 3/24
Electronics:
•
Integrated by: 3/20
Thermal:
•
Integrated by: 3/20
Software:
•
Integrated by: 3/18
Testing:
•
TVAC 1st week of April
at LMCO
Today
Purpose and Objectives
Schedule
Manufacturing Status
Beginning of
Full System Tests
Budget
9
OPTICAL AND MECHANICAL
Purpose and Objectives
Schedule
Manufacturing Status
Budget
10
Mechanical Overview
Structural Panels
Maximize radiative surface area
Provide mounting to other components
Create stand-alone electronics module
Focusing Mechanism
Ensures optics are placed within tolerance
Allows focus to be changed if needed
Bus Interface Tabs
Mechanical mounting to bus
High thermal resistivity
Purpose and Objectives
Schedule
Manufacturing Status
Budget
11
Detailed Design
Ritchey-Chretien Optics Design - Ray Trace Diagram
Incoming
Light Ray
Hyperbolic
Primary Mirror
On-axis ray
9.5 cm
Hyperbolic
Secondary
Mirror
nBn Focal
Plane
14.3 cm
Primary Mirror Specs
Diameter
Vertex Radius
Conic Constant
Surface Irregularity
Surface Finish
Scratch-Dig
Final Coating
Purpose and Objectives
95 + 0.05 mm
407.4 + 0.4 mm
-1.19
λ/10 @ 3.5 µm
120 Å rms
60-40
Gold
Schedule
Secondary Mirror Specs
Diameter
Vertex Radius
Conic Constant
Surface Irregularity
Surface Finish
Scratch-Dig
Final Coating
Manufacturing Status
34 + 0.05 mm
294 + 0.4 mm
-13.92
λ/10 @ 3.5 µm
120 Å rms
60-40
Gold
Budget
12
Component Status
Component
Priority
Source
Progress
Next Steps
Machining
Time
Structure Panels
Mid
In-house
Jig made, 2/4 machined
Machining
Remaining Panels
One Day
Focusing
Mechanism
Mounts
Low
In-house
4/8 Machined
Machining
Remaining parts
< One day
Focusing
Mechanism
Stages
High
In-house
0/3, Delayed due to focal
plane size uncertainty
Final focal plane
fit, machining
1.5 weeks
Secondary
Mirror Mount
High
In-house
Stock Squared
Machining part
3 days
Bus Interface
Tabs
Mid
In-house
0/3
Machining
2 Weeks
Fasteners,
Springs, Pins
Mid
McMaster
Arrived
None
N/A
Micrometers
High
Altos
Photonics
Ordered
Wait for Arrival
Scheduled
arrival
2/11
Purpose and Objectives
Schedule
Manufacturing Status
Budget
13
Component Status
Component
Priority
Source
Progress
Next Steps
Lead Time
Bandpass
Filter
Low
Edmund
Optics
In-house
Assembly
None
Cold Stop
Low
In-house
Finished CAD model
Machining,
Painting, and
Assembly
None
Primary &
Secondary
Mirrors
High
In-house,
Denver
Metal, etc.
Started machining mirror
blanks to be sent out for
coating
Machining,
Coating,
Machining,
Coating, and
Assembly
4 weeks
PSF Testing
Optics & Laser
High
Lockheed
Martin,
Thorlabs
Once mirror cost
determined, be able to
know how many testing
optics we can afford
Assembly and
2-3 weeks
surface treatment
Purpose and Objectives
Schedule
Manufacturing Status
Budget
14
Future Work
 Determine suppliers to
diamond turn mirror blanks
• Cost & Lead time
 Hand polish extra mirrors
 Manufacture cold stop
 Find 3.39 um HeNe laser for
PSF testing
 Purchase or borrow required
optics for PSF testing
Purpose and Objectives
Schedule
 Finish Machining
Components
 Paint Structural Panels
 Integration and assembly of
components and
mechanisms
 Focusing Procedure (PSF)
 Wire Harnessing and
Thermal Braid Mounting
Manufacturing Status
Budget
15
THERMAL
Purpose and Objectives
Schedule
Manufacturing Status
Budget
16
System and Hardware
 Cooling
• Passive cooling using high emissivity radiators
• Active cooling using thermal electric coolers
 Isolation
• Interface panels isolate from conduction
• MLI Isolates from radiation
Thermal Sensors
8 Total
Radiators
MLI Layers
Thermal Electric Coolers
White Paint
Not Shown in Model
• MLI Insulation
• Thermal Epoxy
Thermal Strap
Bus To Structure
Titanium Panels
Purpose and Objectives
Schedule
Manufacturing Status
Budget
17
Component Status
Component
Priority
Source
Progress
Platinum RTD’s Low
QTI
Sampled and tested in Integrate to the
house
system and test
None
Thermal
Electric
Coolers
Med
Laird
Components selected
and samples in house
Test samples and
order system
components
2 Weeks
White Paint
Low
Krylon
Component selected
and supplier located
Purchase and coat
the outer radiators
Less then
1 Week
Thermal
Braids
Low
McMaster
Component selected
and mounting
creation in progress
Order straps and
integrate to the TEC
interface
Less then
1 Week
Titanium
Interfaces
Med
McMaster
Beginning creation of
the set-ups and paths
Machine all three
interfaces
None
MLI
High
Dunmore/
Lockheed
Ordered
Receive and Integrate 3 Weeks
Thermal Epoxy Low
McMaster
Epoxy selected
Will buy when
needed for assembly
Purpose and Objectives
Schedule
Next Steps
Manufacturing Status
Budget
Lead Time
Less then
1 Week
18
Future Work
 High priority
• Machine the three titanium interface panels needed
structure completion.
• Long machining time.
• Obtain & assemble MLI and integrate to the system.
• Potential for long lead time.
• Assemble TEC stack and integrate to the focal plane.
• Delicate work with fragile components.
 Normal Priority
• Coat all radiating surfaces in white paint.
• Integrate the thermal braids to the structural panels using
epoxy.
• Integrate thermal sensors to components.
Purpose and Objectives
Schedule
Manufacturing Status
Budget
19
ELECTRONICS
Purpose and Objectives
Schedule
Manufacturing Status
Budget
20
Electrical Overview
Custom Boards
• Power and Thermal Board
• Shorter lead-time
• Low cost
• Required to power Image Processing
Board
• Required to control Thermoelectric
Coolers
• Image Processing Board
• Long lead-time
• High cost
• Required to capture an image off of
the sensor
Purpose and Objectives
Schedule
Manufacturing Status
Budget
21
Component Status
Printed Circuit
Board
Schematics
Schematic
Review
Layout
Layout
Review
Ordered
Image
Processing
Done
Done
Placement
This Friday
Monday
Power and
Thermal
In-Progress
In-Progress Placement
This Friday
Monday
(Feb 6th)
(Feb 9th)
(Feb
6th)
• Schematics Reviewed by
• Dr. Lawrence
• Bobby
• Trudy
• Lockheed
• Internal Members
(Logan and Jesse)
• Layout
• In-Progress
• Got quote from fabricator
Purpose and Objectives
Schedule
Manufacturing Status
Budget
(Feb 9th)
Future Work
Bring Up Plan
 Order two Power and Thermal Boards
• Professionally assemble one board at
Advanced Assembly
• Hand assemble other board
 Order one Image Processing Board
• Too complex to assemble by hand (BGAs, etc…)
 Work on FPGA logic and software during
fabrication and assembly
Purpose and Objectives
Schedule
Manufacturing Status
Budget
23
SOFTWARE
Purpose and Objectives
Schedule
Manufacturing Status
Budget
24
Software Overview
Purpose: Determine the angular velocity vector of a target object
from a sequence of images and report this solution to the bus
System Control
Communicate with LMCO Bus & parse bus commands
Gather data from power board
Command TEC temperature set-point
Image processing
Filter image
Determine delta vectors
Determine Angular
Determine rotation attitude
Velocity from Sequence
Compress raw image for transfer to bus
of Images
Purpose and Objectives
Schedule
Manufacturing Status
Budget
25
Component Status
Component
Priority
Source
Progress
Next Steps
Dev Time
Bus
Communication
Module
Low
In-house
Implemented and Tested
None
None
Image Interface
Module
Med
In-house
Module Implemented
Testing
1 week
Rate Determination
Algorithm
High
In-house
Working with MATLAB
simulation to quantify error
Rate Portion
Implementation,
Characterization
4 weeks
Optical Flow
Module
High
In-house
Optical flow implemented in
MATLAB
C/C++
Implementation
2 weeks
Thermal Control
Module
Med
In-house
Design Started
Finish Design, Begin
Implementation
3 weeks
Noise Reduction
and Image
Compression
Low
In-house
Researched
Implement Best
Options
1 week
Purpose and Objectives
Schedule
Manufacturing Status
Budget
26
Future Work





Test image interface module
Implement angular velocity determination in C/C++
Implement optical flow in C/C++
Implement Thermal Control Module
Integrated Image Capture Test
Purpose and Objectives
Schedule
Manufacturing Status
Budget
27
TESTING
Purpose and Objectives
Schedule
Manufacturing Status
Budget
28
System Testing Overview
 Integrated System Thermal Test:
• Verify thermal control system can
maintain the focal plane at its
operating temperature of 150K in
the presence of the heat load from
the bus under representative
environmental conditions (vacuum
and cold surroundings)
 Integrated System Optics Test
• Verify that the system can capture
an image sequence and determine
the angular velocity vector of the
target from the captured sequence
Representative Image
Purpose and Objectives
Schedule
Manufacturing Status
Budget
29
Component Status
Integrated Phoenix
Hardware
Bus Simulator
Cooling Jacket
(filled with dry-ice
& alcohol slurry)
Purpose and Objectives
Schedule
Manufacturing Status
Budget
30
Component Status
Component
Priority
Source
Progress
Next Steps
Lead Time
Cooling Jacket
Low
McMaster,
in-house
Steel stock in-house
Machining and
Assembly
None
Cold
Background
Low
McMaster,
in-house
Steel stock in-house
Machining and
Assembly
None
Test Target
High
In-house
Possible surface
Assembly and
1 week
treatments identified
surface treatment
(paint, surface roughness,
oxidation, etc…)
Collimating
Optics
High
Alkor
Provisional partselection: plano-convex
lens
Order Lens
4 weeks
Bus Simulator
Low
In-house
Software interface
complete, electrical
interface defined
Electrical
interface
assembly
1 week
Purpose and Objectives
Schedule
Manufacturing Status
Budget
31
Future Work
 Machine cooling jacket, background, bus simulator
• Not high tolerance or complex
 Seal cooling jacket and background
• Braze seams to prevent coolant leaks
 Finalize collimating optic
• Dependent on optics path forward
 Coordinate Thermal Vacuum testing with Lockheed
 Finish subsystem test procedures
• Finalize details
• Procedures for optics contingencies
Purpose and Objectives
Schedule
Manufacturing Status
Budget
32
BUDGET
Purpose and Objectives
Schedule
Manufacturing Status
Budget
33
Overall Cost Plan
Total Funds Available: $20,000
($5000 ASE Dept + $15000 Customer)
$4,658
23%
$3,795
19%
$990
5%
Component Status
Cost
Purchased
$ 1,482.06
To be Purchased
$ 9,857.00
Margin (20 %)
$ 4,000
Contingency
$ 4660.94
Total Project Cost
$ 20,000
$2,142
11%
$4,000
20%
$3,082
15%
$933
5%
$400
2%
Optics
Structures
Thermal
Testing
Electronics
Miscellaneous
Margin
Contingency
Purpose and Objectives
Schedule
Manufacturing Status
Budget
34
Purchased Components
Item Description
Category
Vendor
Price
Quantity
Needed
Cost
Received
BandPass Filter
Optics
Edmund Optics
$ 395.00
1
$ 395.00
Yes
Stock Aluminum
Structures
Metal Super Markets
$ 232.97
1
$ 232.97
Yes
Stock Titanium
Structures
Metal Super Markets
$ 169.35
1
$ 169.35
Yes
Other – Screws,
Punch Pin, etc…
Structures
Mc-Master Carr
$ 197.56
1
$ 197.56
Yes
Micrometer
Structures
Altos Photonics
$ 66.00
3
$ 198.00
No
Platinum RTD’s
Thermal
QTI
$ 0.00
12
$ 0.00
Yes
TEC – 2 Stage
Thermal
Laird
$ 0.00
2
$ 0.00
Yes
Stock Steel
Testing
Metal Super Markets
$ 123.08
1
$ 123.08
Yes
Binding - FFR
Misc.
Ink Spot
$ 47.07
1
$ 47.07
Yes
Shipping
Misc.
N/A
$ 119.01
1
$ 119.01
Yes
Total
$ 1,482.04
Purpose and Objectives
Schedule
Manufacturing Status
Budget
35
Components to Purchase
Item Description
Category
Vendor
Estimated
Price
Quantity
Needed
Cost
Projected
Lead Time
Diamond Tooling
Optics
TBD
$ 3,000.00
1
$ 3,000.00
2-3 weeks
Plating
Optics
TBD
$ 200.00
2
$400.00
1 week
TEC’s 1-Stage
Thermal
DigiKey
$ 15.00
4
$ 60.00
3 days
TEC’s 2-Stage
Thermal
DigiKey
$ 140.00
2
$ 280.00
3 days
TEC’s 5-Stage
Thermal
DigiKey
$ 380.00
1
$ 380.00
3 days
Thermal Braids
Thermal
Mc-Master Carr
$ 75.00
1
$ 75.00
3 days
Thermal Paint
Thermal
Az Technology
$ 350.00
1
$ 350.00
1-2 weeks
Thermal Epoxy
Thermal
Master Bond
$ 500.00
1
$ 500.00
1 week
Insulation
Thermal
Dunmore
$ 500.00
1
$ 500.00
3 weeks
Board PCB’s
Electronics
Royal Circuits
$ 791.00
2
$ 1,582.00
1-3 weeks
Board Components
Electronics
Multiple
$ 750.00
2
$ 1,500.00
1 week
Collimator
Testing
Edmund Optics
$ 500.00
1
$ 500.00
1-2 weeks
Misc. Supplies
Structures/
Testing/Misc.
Multiple
$ 360.00
1
$ 730.00
1-3 days
Total
$ 9,857.00
Purpose and Objectives
Schedule
Manufacturing Status
Budget
36
Financial Pareto’s
Breakdown of Currently Purchased
Components
$2,000.00
Breakdown of Components to Purchase
100%
$1,800.00
90%
$1,600.00
80%
$1,400.00
70%
$1,200.00
60%
$1,000.00
50%
$800.00
40%
$12,000.00
100%
90%
$10,000.00
80%
70%
$8,000.00
60%
$6,000.00
50%
40%
$4,000.00
$600.00
30%
$400.00
20%
$200.00
10%
$-
30%
20%
$2,000.00
10%
$-
0%
0%
Raw Cost
Cumulative Cost
Raw %
Cumulative %
Purpose and Objectives
Schedule
Manufacturing Status
Budget
37
CONCLUDING STATEMENTS
38
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)
39
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.
40
BACKUP SLIDES
41
CubeSat Bus Design Constraints
Bus Electrical Constraints
3.3 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 Average
15 W Peak
Command Communication Bus
SPI Slave
High-Speed Communication Bus
Ethernet, Magnetics-Less Differential
Backup Communication Bus
I2C
Regulated Voltage Lines
Bus Structural Constraints
Total Volume
2U (10x10x20 cm)
Total Mass
2.66 kg + 0.1 kg/ - 0.5 kg
42
Critical Project Elements
Critical Element
Subsystem Driving Requirements
Capture Mid Wave
Infrared (MWIR) image
Optical
The payload shall determine the angular
velocity and axis of rotation of an observed
object (O.2), The payload shall use the 3.5 µm
mid-wave infrared (MWIR) wavelength (O.3)
Control focalplane to
operating temperature
of ≤ 150 K
Thermal
The payload shall maintain all components in
their operating temperature ranges (O.4)
Determine angular
velocity vector of object
in sensor field of view
Software
The payload shall determine the angular
velocity and axis of rotation of an observed
object (O.2)
Provide a hardware
platform for the
software
Electrical
The payload shall determine the angular
velocity and axis of rotation of an observed
object (O.2)
Purpose and Objectives
Design Solution
Requirement Satisfaction
Verification/Validation
Planning
43
Functional
Block
Diagram
Purpose and Objectives
Design Solution
Requirement Satisfaction
Verification/Validation
Planning
44
Design Overview
Infrared Optics and Focusing
•
•
Two Mirror Design
Manually adjust position of primary
mirror using micrometers
• Precision: 1 micron
• Total Travel: 5 mm
Bus Interface Side
45
Design Overview
Infrared Optics and Focusing
•
•
Two Mirror Design
Manually adjust position of primary
mirror using micrometers
• Precision: 1 micron
• Total Travel: 5 mm
Hyperbolic
Primary Mirror
Hyperbolic
Secondary
Mirror
Focal-Plane
3-Axis Focusing
Mechanism
Micrometer
Primary Mirror
Secondary Mirror
Purpose and Objectives
Design Solution
Requirement Satisfaction
Verification/Validation
Planning
46
Design Overview
Thermal Control
•
•
•
Thermal Electric Cooler
Thermal braids to exterior radiator panels
Focalplane requires cooling to 150 K for
operation in infrared band
Purpose and Objectives
Design Solution
Requirement Satisfaction
Verification/Validation
Planning
47
Design Overview
Thermal Control
•
•
•
Thermal Strap
Thermal Electric Cooler
Thermal braids to exterior radiator panels
Focalplane requires cooling to 150 K for Image Sensor
operation in infrared band
Module
Thermoelectric
Coolers
MWIR Focalplane
Operates ≤ 150 K
Purpose and Objectives
Design Solution
Requirement Satisfaction
Verification/Validation
Planning
48
Design Overview
Electronics
Software
•
•
•
•
•
•
MWIR Sensor module
Image Processing board
Power and thermal control board
Image
Purpose and Objectives
Design Solution
Requirement Satisfaction
Capture and save IR image
Determine rate of object in FOV
Verification/Validation
Planning
49
Design Overview
Electronics
Software
•
•
•
•
•
•
MWIR Sensor module
Image Processing board
Power and thermal control board
Image
Capture and save IR image
Determine rate of object in FOV
Power and Thermal
Control Board
Sensor Interface
Module
Purpose and Objectives
Design Solution
Requirement Satisfaction
Verification/Validation
Image Processing
Board
Planning
50
OPTICS BACKUP
51
Requirements
Requirement
Driver
The optical system shall have a diffraction limited spot
size of less than 20 µm at a 3.5 µm wavelength
Detector pixel size
The optical system shall image at the 3.5 µm wavelength
Customer
The optical system shall have an SNR of no less than 6
Image processing
The optical system tolerances shall change the spatial
cutoff frequency by no more than 15 percent
Imaging quality &
mechanical feasibility
52
Mirror Fabrication Process
1.
2.
3.
4.
5.
6.
Mirrors out of aluminum blanks in AES shop
Thermal cycled & re-machined to remove stresses
Sent to Denver Metal Finishing for nickel plating
Sent to TBD supplier to be diamond turned
Gold deposited on mirrors in CNL thermal evap
System specifications tested using PSF testing
Process
Cost
Nickel Plating
$300
Diamond Turning
~$3000-5000
Gold Deposition
$200
Estimated Total
$3500-5500
53
Bandwidth
 COTS bandpass filters work for our application
 Low cost, low lead time
 Pass band: 3.32 – 3.60 µm
3.46 µm Bandpass Filter
2.OPT.2
Transmittance
Capture images at the 3.5
µm wavelength
Wavelength (nm)
Overview
Baseline Design
Optics
Thermal
Electrical/Software
Testing
Logistics
54
Spot Size
Spot sizes calculated using Zemax simulations
Optically
Limited
Designs
Diffraction
Limited
Designs
On & Off Axis Beams
Diffraction Limited
2.OPT.1
Diffraction limited spot
size < 20 µm at λ =3.5 µm
Overview
Baseline Design
Optics
Thermal
Electrical/Software
Testing
Logistics
55
Sampling


Sampling size is the detector pixel size
(i.e. 12 µm)
Nyquist Theorem
•

Diffraction limited spot
size < 20 µm at λ =3.5 µm
sampling size = optical spot size
Oversampling
•
2.OPT.1
sampling size < optical spot size
Nyquist
Sampling
Normalized Diffraction Limited Spot Cross Section
Oversampling
Spot Size
Overview
Baseline Design
Nyquist sampling versus over-sampling,
exaggerated for effect
Optics
Thermal
Electrical/Software
Testing
Logistics
56
Signal to Noise Ratio (SNR)
 Assuming operation at 3.32-3.60 µm wavelengths
 Primary source of noise: thermal background and dark
current
 SNR ≥ 6 reduces probability of false alarms from noise
to ~10-12 in sensing and tracking functions
Signal to Noise Ratio vs. Range from Target
2.OPT.3
SNR
SNR ≥ 6
SNR = 6.28
Range (km)
Overview
Baseline Design
Optics
Thermal
Electrical/Software
Testing
Logistics
57
Probability of Detection
 Kamerman estimation
• Assumptions: SNR > 2, 10−12 < 𝑃𝑓𝑎 < 10−3
1
𝑃𝑑 = ∗ 1 + erf
2
1
1
+ 𝑆𝑁𝑅 − 𝑙𝑛
2
𝑃𝑓𝑎
 Thus for SNR > 6 and 𝑃𝑓𝑎 < 10−10 the probability
of detection is essentially 100 percent
58
Thermal Stresses
 Z-axis thermal expansion
• Focusing @ 300K
• Take images @ 230K
• dL = 233 µm
𝛼𝑎𝑙𝑢𝑚 = 22.2 ∗ 10
𝑑𝐿 = 𝛼𝑎𝑙𝑢𝑚 𝐿 𝑑𝑇 𝑑𝑇 = 70 𝐾
𝐿 = 0.15 𝑚
−6
1
𝐾
 X,Y-axis thermal expansion
• Will not change focus
 Steady-state temperature operation
• Max dT ~ 4K (Simulink simulation)
• dL ~ 10 µm
• Far below tolerances and depth of focus
z
y
x
59
Aberrations
 Seidel Coefficients (in 𝜆):
60
nBn Detector
InAs N-doped Semiconductor Layers
Sandwiching 100 nm AlAsSb Barrier
Reduced Dark Current, Operating
Temp. of 140+ K vs 77 K (Traditional)
Figures courtesy of: Applied Physics Letters, October 9, 2006 - 151109
61
Imaging Results
Simulated Image of Optical System
Note blur at
edge of field of
view
Overview
Baseline Design
Optics
Thermal
Electrical/Software
Testing
Logistics
62
TESTING BACKUP
63
Cooling Jacket
64
Test Target Surfaces
 Paint
• White and black paint are both high
emissivity at IR
• Paint emissivity much higher than
polished metal (0.85 versus 0.05) and
net emissivity a function of paint
thickness
 Surface roughness
• Increased surface roughness increases
emissivity (0.30 versus 0.10, varies with
surface roughness)
 Oxidation
• Oxidized metal has higher emissivity
(0.40 versus 0.10 for aluminum, varies
depending on degree of oxidation)
Images from http://www.reliableplant.com/Read/14134/emissivity-underst-differencebetween-apparent,-actual-ir-temps
65
Test Target Contrast
 Background at 195K (dry ice)
and emissivity of 0.03
(aluminum foil)
 Target
• Temperature: 295K
• Mean emissivity: 0.3036
• Minimum emissivity: 0.1154
(polished copper)
• Maximum emissivity: 0.4918
(partially oxidized copper)
66
Collimating Optic
 Plano-convex lens
•
•
•
•
•
•
Between payload and test target
Cold background behind target
$500
Four-week lead time
Less than full aperture diameter which reduces contrast
1m or 2m focal length
• 3.24cm or 4.68cm test target
 Parabolic Mirror
• On far side of test target
• Payload is background
• Possible background uniformity issues but can crop
image
• Target obstructs field of view which reduces contrast
• $465
67
Optics Contingency (1)
 Integrated System Thermal Test
• Unchanged, uses unsurfaced
mirrors as thermal masses
 Electronics
• Power board fully testable
• Image close target without optics
to verify image sensor interface
• Image sensor interface core has
test mode to verify hardware
without image sensor
Image Capture
Command
Main Processor
and Memory
Test Image
Image Sensor
Interface Core
68
Optics Contingency (2)
 Software
• Feed algorithm simulated
images to verify optical flow and
rate determination modules
• Have option to replace image
sensor interface core with new
core that provides simulated
images, from the perspective of
the software this is identical to
nominal operations
Test Computer /
FPGA Core
Unmodified
Software Modules
 Mechanical
• Focusing mechanism still fully
testable
69
LOGISTICS BACKUP
70
Work Products Breakdown Structure
Structures
Electronics*
Thermal
Software
• Primary &
Secondary Mirror
Drawings
• Rev 1 Board
Schematics
• Block Diagram of
Thermal Paths
• Communications
Module
• Rev 1 Board Layout
• Focusing
Mechanism
Drawings
• Rev 1 Populated
Board
• Resistance Values
for Thermal
Contacts
• Sensor Interface
Module
• Thermal Mounting
Hardware
Drawings
• Load/Vibration
Analysis on Mirror
Supports
• Drawing Package
for all Components
• Drawing Tree
• CAD Model
• Machined
Components
• Rev 1 Board Test
Report
• Rev 2 Board
Schematics
• Rev 2 Board Layout
• Rev 2 Populated
Board
• Rev 2 Board Test
Report
• Integrated
Electronics
• Simulink Model
• Thermal Desktop
Model
• Integrated Thermal
System
• Rate
Determination
Module
• Image Interface
Module
• Temperature
Control Module
Optics
• Thermal
Background
Calculations
• Photon & SNR
Budgets
• Mirror Designs
• Baffle & Cold-Stop
Design
• Focused Optical
Assembly
• OP Code Dictionary
• Software
Reference
Document
• Software Package
• Assembled Units
* These deliverables pertain to both the Power and C&DH Board
71
Work Products Breakdown Structure
Management
Testing
Systems
• PDD
• Procedure for TVAC Test
• CDD
• Procedure for Optics Test
• Test Procedures per
Subsystem
• PDR Presentation
• Integration Procedures
• ICD per Subsystem
• CDR Presentation
• MSDS Documentation
• Integrated Payload
• FFR
• Liner for Optics Test
• MSR Presentation
• Payload Bracket for
Optics Test
• TRR Presentation
• AIAA Paper
• Payload to Bus ICD
• SFR
• Aligned & Focused
Collimator
• Test Target
• Bus Simulator for TVAC
Test
• Test Results
72