Design Review Spartan IR Camera
E Loh, Physics-Astronomy Department, Michigan State University
East Lansing, 22 May 2001
1 Science Goals (ref: NSF proposal)
2 Optical Design (ref. “Optical Design”)
–Optical alignment (ref: “Alignment” & “SOBER”)
3 System Design & Electronics (ref. “Electronics”)
4 Mechanical Design (ref. “Mechanical Design”)
5 Budget & Schedule (ref. “Budget & Schedule”)
The Team
• Jason Biel, technician
– Measurements for vacuum design
– Electronics designer & technician
• Mike Davis, graduate student
– Optics
• Owen Loh, Okemos High, volunteer
– Finite-element analysis
– Drafting
• Tom Palazzolo, head, Phys-Ast shop
– Mechanical shop, design advice, contact for mechanical designers
& job shops
• Jack Baldwin, Brooke Gregory, Ron Probst, Dan Edmunds,
Phys-Ast EE, advisors
• E Loh
22 May 2001
DR SOAR Spartan IR Camera
2
1. Science Goals
Tip-tilt corrected imaging in the J, H, & K bands
• To cover the wide, corrected field (5’)
• To resolve FWHM of median seeing (0.15–-0.23”)
• To resolve high-contrast features at the diffraction limit
(0.08” @H & 0.11” @K)
22 May 2001
DR SOAR Spartan IR Camera
3
Point-spread Function with Tip-Tilt Correction
• Point spread function is not a gaussian
• Diffraction spike
40 H
KJ
30
J
H
K
Strehl Ratio
median
top 25%
0.05
0.15
0.12
0.30
0.28
0.50
20
K-tt
Intensity [arcsec -2]
Band
Top quartile
20
10 V
15
H-tt
0
10
J-tt
5
K
V-tt
0
0.1
0.2
0.3
Median seeing
V
0
0
22 May 2001
DR SOAR Spartan IR
0.05
0.1
0.15 0.2
q [arcsec ]
0.25
0.3
Figure 2 Point-spread functions for median seeing with
tip-tilt correction (solid lines) and without correction
Camera
4 is
(dashed line; K and V bands only). Shown in the insert
the tip-tilt corrected PSF with top quartile seeing.
Image Width
• Sub 0.5” images w/o tip-tilt
• 0.15-0.23” images w tip-tilt
• Telescope optics preserves images
Telescope degradation.
Goodyear CDR
0.5
F W H M [a r c s e c]
Natural/median
0.4
Natural/top quartile
0.3
0.2
0.1
0
TT/median
TT/top quartile
Diffraction
0.5
1
1.5
2
wavelength [ m]
2.5
Figure 2 Image size (FWHM) for natural seeing, for tip-tilt
correction, and for diffraction (from top to bottom). For median
seeing with tip-tilt correction, the points show the effect of telescope
22 May 2001 degradation with the AOS
DR specification
SOAR Spartan
IR Camera
and the
Raytheon structure
function presented at CDR.
5
2. Optical Design
• Concept
• Image Quality
• Tolerances
22 May 2001
DR SOAR Spartan IR Camera
6
Optical Concept
• Requirements
– Large number of pixels [ 2 x 5’ / 0.08” = 7500 pixels ]
– Large telescope image [ 5’ x 4.2m x 16 = 100mm square]
• Rockwell 2048x2048 HgCdTe detector
– 4 detectors & 7500 pixels  two plate scales
• Reflective optics  large telescope image
• Off-axis collimator & camera mirror
– Parent design: two paraboloids
• Perfect image for 1:1 & small field
– Real design for change in plate scale
• Adjust conic constants, distances
• Field flattening lens
22 May 2001
DR SOAR Spartan IR Camera
7
Design
•
•
•
•
Four 20482 detectors
Two plate scales: 0.08 & 0.04”/pixel
20 filters near pupil
Focal plane mask
– coronagraphy
– spectroscopy
22 May 2001
DR SOAR Spartan IR Camera
8
Image Quality: Spot Diagram
• 9 Field points in a grid. Corners are corners of 4 detectors.
• H band
Airy disk
f/11
f/21
22 May 2001
DR SOAR Spartan IR Camera
9
Image Quality: Strehl Ratio
• 9 Field points in a grid. Corners are corners of 4 detectors.
• Strehl is very high for diffraction sampled cases, f/21 in H and K
bands
f/21
Sampled for diffraction limit
J
H
K
22 May 2001
f/11
0.980
0.987
0.980
0.892
0.862
0.892
0.969
0.998
0.969
0.903
0.904
0.903
0.980
0.945
0.980
0.919
0.977
0.919
0.991
0.994
0.991
0.940
0.925
0.940
0.984
0.999
0.984
0.951
0.941
0.951
0.991
0.971
0.991
0.957
0.993
0.957
0.994
0.996
0.994
0.964
0.956
0.964
0.990
0.999
0.990
0.971
0.965
0.971
0.994
0.983
0.994
0.974
0.994
0.974
DR SOAR Spartan IR Camera
10
Tolerances
• Error budget
– Loss of Strehl of ~0.07mag
• Alignment
• Manufacturing
Quantity
 Strehl [mag]
Alignment:
0.042
38 parameters
Manufacturing:
0.003
3 parameters
22 May 2001
Surface
irregularituies
0.016–0.038
Total
0.061–0.083
DR SOAR Spartan IR Camera
11
Alignment Tolerances
Alignment Tolerances of the Optical Elements
Element
Positional Tolerance
x
y
z
mm mm mm
1 Window
NA
NA
NA
2 Focal surface
1.00 1.00 0.30
3 f/21 collimator
0.81 0.28 0.19
4 f/11 collimator
0.41 0.15 1.01
5 Fold mirror 1
NA
NA 0.69
6 Filter
NA
NA
NA
7 Lyot stop
NA
NA
NA
8 f/21 camera mirror 0.67 0.25 0.40
9 f/11 camera mirror 0.27 0.17 0.49
10 Fold mirror 2
NA
NA 0.16
11 Lens
0.48 0.32 0.33
12 Detector plane
NA NA 0.03
22 May 2001
6mil
Angular Tolerance
x
y
z
mrad mrad mrad
NA
NA
NA
6.38 6.38
NA
1mil over 6in
0.30 0.52 6.10
0.21 0.42 3.14
0.17 0.26
NA
NA
NA
NA
NA
NA
NA
0.26 0.52 4.80
0.17 0.23 1.86
0.31 0.47
NA
2.27 11.34
NA
0.64 0.64
NA
DR SOAR Spartan IR Camera
12
Manufacturing Tolerances
•
•
•
Focal lengths are absorbed in
focus
SORL can manufacture conic
constants
Surface irregularity
– Peak-to-valley is l/16 to l/4.
l = 633nm
Element
 Strehl [mag]
Flat SF
Real SF
Window
l/4
0.0045
0.0004
Collimator
l/16
0.0062
0.0032
Fold #1
l/16
0.0062
0.0039
Filter
l/4
0.0045
0.0037
Camera
l/16
0.0062
0.0032
Fold #2
l/16
0.0062
0.0013
Lens
l/4
0.0045
0.0000
0.038
0.016
Total
22 May 2001
Quality
DR SOAR Spartan IR Camera
13
Alignment with SOBER
•
•
Align at room temperature with
point source, SOBER, & CCD
LED & pinhole
SOBER
– f/16 beam
– Move SOBER & shift stop to
mimic pupil at 10m
– z stage mimics curved focal
surface of telescope
Sliding stop
– Tolerances 1mm & 1º
– Image in IR? TBD
Lenses
z stage
R- stage
ISB surface
Soar Beam Simulator
22 May 2001
DR SOAR Spartan IR Camera
14
Alignment Indicator
80.
80.
2
0
70.7
81.5
70.7
- 2
- 4
73.5
81.6
4
@
D
4
80.
D EncEnergy %
D EncEnergy %
@
D
• Intensity of 9 field points indicates error
- 0.5
0
80.
0
70.7
81.5
70.7
73.5
81.6
73.5
- 2
73.5
0.5
1
Y-decenter of collimator 0.34mm
22 May 2001
80.
2
- 4
- 1
80.
- 1
- 0.5
0
0.5
1
X-tilt of fold #1 of 0.2mrad
DR SOAR Spartan IR Camera
15
H L@
D
Test of Alignment
10
Defect: I7<I9
x-position of collimator; wrong
E- E aligned
%
5
1
2
3
4
5
6
7
8
9
0
-5
-10
-15
-20
y-tilt of lens; right
-20
-10
0
10
20
30
Defect: I5<I8
x-tilt of fold #1
22 May 2001
DR SOAR Spartan IR Camera
16
3. System Design & Electronics
•
•
•
•
•
System
Electronics
Software
Motors
Vacuum
22 May 2001
DR SOAR Spartan IR Camera
17
System Design
Detector
Camera Controller
Detector
Camera Controller
Detector
Camera Controller
Detector
Camera Controller
Stages
Motor Controller
In vacuum
Pressure Sensor
Fiber optic
In control rack
Umbilical
PC
NI 6533
RS232
RS232
DeviceNet
RS232
On camera
Ethernet
Legend
Custom
Commercial
22 May 2001
Observer
Data Archive
Telescope Control
Elsewhere
DR SOAR Spartan IR Camera
18
Umbilical Card
Camera card
• Provenance
One of 4 channels shown
– CCD system
Fiber-optic
tranceiver
Master clock
Logic Analyzer
Serializer
deserializer
Test pod
For debugging
Existing CCD Software
on Alpha
FIFO
NI 6533 interface
DRV11 interface
In FPGA
NI 6533
22 May 2001
Laptop-type power supply
DR SOAR Spartan IR Camera
19
Camera Card
• Provenance: CCD camera
• 4 analog channels for 4
quadrants
Timer &
clock generator
Buffer
Detector
Diodes
Logic Analyzer
Amplifier &16-bit ADC
(2 12-bit ADC)
Instruction
Fixed voltages
(digital pot)
Serializer
deserializer
Temperature
Fiber-optic
tranceiver
Test pod
In FPGA
Laptop-type
power supply
Phase-locked
loop
Umbilical card
22 May 2001
DR SOAR Spartan IR Camera
20
Umbilical Card
• 3U 100160 mm
• Tested w/ CCD software
To existing computer
Fiber optic
to 4 detectors
NI 6533
FPGA
7V in
To logic analyzer
22 May 2001
160mm
DR SOAR Spartan IR Camera
21
Camera Card
• 3U 100160 mm
• Low crosstalk
– 5-mil between signal & ground layers
• 2.5ms/pixel
• 4 channels
• Power: 1.4W
• Delivery expected in 2 weeks
7V in
Signal chains
Fiber optic
Flex cables to detector
22 May 2001
Neck between
analog & digital circuits
DR SOAR Spartan IR Camera
FPGA
22
Noise
•
•
•
•
Detector noise is about 10e–; noise on amplifier glow is 5e–.
Electronics noise is 6e–.
Coupling from a saturated channel is about 2e–.
Coupling from clocks on cable is large.
– Sampling signal must wait 100ns after clock transition.
Source
Detector
Glow w 2.5s read
Electronics
Opamp
FB resistor
Offset reference
Bias gate
Coupling
Saturated signal on cable
Clock on cable
ADC (difficult to estimate)
Saturated signal on card
22 May 2001
DR SOAR Spartan IR Camera
Noise e- Segregated
~10
5
5.7
4.5
3.5
0.6
0.06
0.2
180 yes
2 ? yes
1.3 ?
23
Detector Card
• Card butts on 2 sides
• Connects to camera card with 5 flex
cables, which are thermal resistors.
• 3 layers with 5-mil G10.
Flex cables
Electrically isolated straps
to nitrogen dewar
ZIF socket
Detector
22 May 2001
DR SOAR Spartan IR Camera
24
Software
• Functions [copied from Optical Imager]
–
–
–
–
–
Control detector
Scripting
Communicate with motors
Communicate with telescope control system
Communicate with user
• ArcView
– Used for all SOAR instruments
– CTIO will debug ArcView with Optical Imager, the commissioning
instrument
• LabView, “visual programming”
– Independent of hardware  obsolescence is obsolete
– Self documenting
– Easy to do. ArcView costs < 1 man-year
22 May 2001
DR SOAR Spartan IR Camera
25
Software Tasks
• Design
– Use commercial parts with LabView drivers
• Modify ArcView
– Computer send commands and receives data from camera
controller through NI 6533 card.
• Replace Leach controller & driver with NI 6533 card.
• Our card has a 4k sample FIFO
– 0.6ms margin for 4 detectors reading simultaneously
–
–
–
–
Write software for summing pictures
Change software for formatting picture
Change motor controls
Add temperature & vacuum sensing
22 May 2001
DR SOAR Spartan IR Camera
26
Motion
• Phytron stages DT-90 & MT-85
–
–
–
–
–
Vacuum compatible
Stepper motor
Indexing switch
Limit switches
Open loop; controller stores position
• Controller
– RS232 to computer
– LabView
– Heat
• Shutoff power? Cooler?
22 May 2001
DR SOAR Spartan IR Camera
27
Vacuum Measurement
• Granville-Phillips ion gauge
– Computer readout via DeviceNet
– LabView
– 12W; need to shut off
22 May 2001
DR SOAR Spartan IR Camera
28
4 Mechanical Design
• Cryogenic optical box
– A-frame attachment to vacuum enclosure
– Analysis of flexure
• Vacuum enclosure
– Analysis of stress
– Transfer of forces from A-frame to instrument mounting box (ISB)
• Mechanisms using warm stages
– Layout
– Proof of concept
• Flexure
• Heat load
• Operating temperature of stage & optics
22 May 2001
DR SOAR Spartan IR Camera
29
Cryogenic Optical Box
• Symmetric box having two
plates equidistant from
optics.
– Gravity vector is in plane.
– Optics supported by both
plates.
• Torque perpendicular
to plates
• Box is attached near focal
surface of telescope
– Rotation of optical box
causes no boresight
error.
22 May 2001
DR SOAR Spartan IR Camera
30
A-frame Attachment
• Connect cold optical box
to warm vacuum
enclosure
• Complies with shrinkage
of optical box
Weak
for thermal compliance
Strongest; max sag:
14m or 0.04”
– Web weak in z
• Hold box w/o sag
Al leg
G10 web
– Web strong in x & y
• Heat load is 0.7 W for 4 Aframes.
G10 ring
Section removed
for clarity
Bolt to
optical box
Safety stop
22 May 2001
DR SOAR Spartan IR Camera
Bolt to warm
vacuum enclosure
31
•
•
Gravity parallel to mounting plate.
(Causes boresight error)
First approximation
– Optical box rotates 40mrad as a
unit
– Sag is 14m at telescope focus.
•
Rotation of Optical Box
0–155mrad
34–46mrad
More precisely
– Error is greater for gravity
perpendicular to mounting plate.
– Rotation within box is 2.3mrad
peak-to-peak
– Boresight shifts 0.007”.
22 May 2001
DR SOAR Spartan IR Camera
32
Vacuum Enclosure
• Aluminum plate, mostly 1/2”
• Max stress is here
– Max is tensile strength / 2.2.
– Code for pressure vessels is 3.5.
– Is this OK?
22 May 2001
DR SOAR Spartan IR Camera
33
Transfer of Forces to Bolts on ISB
• Does the vacuum enclosure transfer forces between the Aframes and the bolts on the instrument mounting box (ISB)
without sag? Yes. Sag is 2m.
Optical box
Bolts to
A-frames
Bolts to ISB
Sides of vacuum enclosure
22 May 2001
DR SOAR Spartan IR Camera
34
Mechanisms
• Two filter wheels
– Loose tolerances
• Focal-plane mask
– 300m along optic axis, 18m in transverse direction
• Collimator insertion
– Tilt 5mrad (1”) as instrument turns for boresight with tip-tilt sensor
• Camera mirror insertion
– Tilt 5mrad as instrument turns
• Rotate lens-detector by 112.7±0.6mrad
Difficult
– Tilt 0.2mrad (30m over 150mm)
• Move lens-detector assembly for focusing
22 May 2001
DR SOAR Spartan IR Camera
35
Layout of Mask & Filter Wheel
• Load is balanced  Easy to meet tolerances.
• Phytron DT-90 rotational stages
– Integrated stepper motor, indexing switch, limit switch
– Spring constant 2mrad/(N-m). Wobble is ±15mrad (Clarification
needed.)
Optical box
200
200
100
Vacuum enclosure
Rotation stage
100
DT - 90
100
200
300
DT - 90
100
400
-100
-100
-200
-200
Mask wheel
22 May 2001
200
300
400
Filter wheel
DR SOAR Spartan IR Camera
36
Layout of Mirror Insertion
• Mirrors must be balanced to meet 5mrad tolerance.
Vacuum enclosure
Rotation stage
Mirror
200
Optical box
200
CW
out
CW
in
100
100
DT - 90
Mirror
in
100
200
300
-200
400
Mirror
in
100
Counterweight
f/21 collimator
200
300
400
Mirror
out
-100
Background mirror
-200
22 May 2001
CW
in
DT - 90
Mirror
out
-100
CW
out
f/11 camera
DR SOAR Spartan IR Camera
37
Proof of Concept: Insert f/21 Mirror
• Requirements. Cold mirror — warm stage — cold optical box
–
–
–
–
–
Support with tilt < 5mrad
Keep mirror cold
Keep stage warm
Minimize heat load
Comply with thermal expansion
• Precepts
– Balance load
– Use G10 A-frames to control conduction & comply with thermal
expansion
– Shield stage from cold to control radiation
– Allow stage to absorb radiation from warm vacuum enclosure
22 May 2001
DR SOAR Spartan IR Camera
38
Mirror Insertion
4 A-frames
f/21 collimator
Center mass
Counterweight
DT90 rotational stage
4 A-frames between
stage & bracket (hidden)
Bracket attaches
to optical box
22 May 2001
DR SOAR Spartan IR Camera
39
Results for f/21 Insertion
•
•
•
•
A-frames have 1x1x5mm legs.
Balance within 1mm.
Wrap stage in 10 layers of aluminized mylar.
Results
– Conduction is 170mW
– Tilt is 2mrad; tolerance for boresight alignment is 5mrad.
– Sag with mirror vertical is 8m; tolerance for internal alignment is
0.8mm.
– Sag with mirror horizontal is 4m; tolerance for focus is 15m.
– Temperature of mirror is 88K.
– Temperature of stage is 2K below ambient. (Area of radiator is 10%
that of the stage.)
22 May 2001
DR SOAR Spartan IR Camera
40
5 Budget & Schedule
•
•
•
•
•
Budget
Contingency
Descope
Risk to budget
Schedule
22 May 2001
DR SOAR Spartan IR Camera
41
Budget
• Not allocated or charged: Majority of electrical engineer,
mechanical engineer, project management, drafting (done so far),
and finite-element analysis.
SUMMARY BY WBS
WBS ITEM
1
2
3
4
5
6
7
M&S
CONTINGENCY TOTAL
%
MECHANICAL
218577
27
58818
277396
OPTICS
188683
34
63729
252412
DETECTOR
317263
5
16045
333309
SOFTWARE & COMPUTERS
49456
59
29021
78478
INSTALLATION AND COMISSIONING
49653
23
11643
61296
SUPPORT EQUIPMENT & SUPPLIES
38822
22
8397
47220
MANAGEMENT, REPORTING, & DOCUMENTING
50610
13
6777
57387
TOTAL
913065
21
194431 1107496
Major Items
WBS Item
Total
1.3
Optical Bench, dewar, enclosure
122,518
1.4
Mechanisms
147,908
2.5
Collimator mirror
63,746
2.6
Camera mirror
75,035
3.1.1 Detector
250,000
3.2
Electronics
52,894
4.1
Software
48,657
22 May 2001
DR SOAR Spartan IR Camera
42
Contingency vs Remaining Tasks
• Tracking of tasks since budget of Aug 2000
–
–
–
–
Electronics design is 17% over budget. ($5k of $29k)
Design of telescope simulator is 65% over budget. ($5k of $8k)
Optics design is 31% under budget. ($6k of $19k)
Overall budget dropped $100k because mechanical design
firmed up, optics shortened, and mirror quotes dropped.
• Contingency is 36% of remaining tasks.
WBS
1
2
3
4
5
6
7
CONTINGENCY AS FRACTION OF REMAINDER
ITEM
ENCUMBERED
CONTINGENCY
%
 %
AMOUNT
MECHANICAL
27
59322
292
37
59110
OPTICS
10
18257
6753
41
70481
DETECTOR
89
282777
(5129)
32
10916
SOFTWARE & COMPUTERS 2
835
360
60
29381
INSTALLATION AND COMISSIONING
0
0
0
23
11643
SUPPORT EQUIPMENT & SUPPLIES
49
19028
(3552)
24
4845
MANAGEMENT, REPORTING, &
0 DOCUMENTING
0
0
13
6777
TOTAL
42
380219
(1276)
36
193155
22 May 2001
DR SOAR Spartan IR Camera
43
Descope
• Descope 2nd plate scale, J, H, K, Ks filters only, spectroscopy &
coronagraphy.
• Descope will be treated as contingency.
– Descoped items will be added as contingency allows.
– Possible formula: spend if
Budgeted Contingency > 1.5 Actual Contingency
WBS
M&S
Total
128439
Second f/ratio
83239
2.5
Collimator mirror
21249
2.6
Camera mirror
25012
Mechanisms
36979
Spectroscopy & Coronagraphy 13200
2.13
Grisms
13200
Spectral filters
32000
2.9
Defer 8 of 12
32000
22 May 2001
Contingency
Total
46958 175397
35658
10624
12506
12528
3300
3300
8000
8000
DR SOAR Spartan IR Camera
44
Risk to Project
• Number of risks covered
– A big item is $100k.
– Labor for optical box, mechanisms, enclosure
is $70k with $30k contingency
• Drafting: 3 mo.
Remaining of
• Internal shop: 7 mo.
descoped
instrument
• External shop: 1 mo.
49%
• Technician: 6 mo.
– Contingency, $193k, covers 2 big risks
– Descope, $175k, covers 2 big risks.
Contingency
27%
Descope
24%
• Descope & contingency  remaining tasks of
descoped instrument
22 May 2001
DR SOAR Spartan IR Camera
45
Schedule Overview
Qtr 4
ID
1
Task Name
SOAR Project
6
Detector
10
Electronics
34
Optical bench, enclosure, and mechanisms
47
Optics
57
Software
62
Integration
68
Instrument finished
69
Install on telescope
22 May 2001
2001
Qtr 1
Qtr 2
50%
Qtr 3
Qtr 4
2002
Qtr 1
Qtr 2
Qtr 3
Qtr 4
2003
Qtr 1
80%
50%
13%
10%
Software
0%
Integration
0
Instrument finished
Install on telescope
DR SOAR Spartan IR Camera
46
2
Detector
• Multiplexer & engineering-grade device delivered.
• Long slack time before science-grade detector is needed.
Task Name
Detector
Qtr 4
1999
Qtr 1
Qtr 2
Qtr 3
Qtr 4
2000
Qtr 1
Qtr 2
Qtr 3
Qtr 4
or
Rockwell multiplexer
Rockwell engineering device
xer
1/19
Rockwell engineering device
Rockwell science-grade device
22 May 2001
11/
Rockwell science-grade device
DR SOAR Spartan IR Camera
47
Electronics
• 7 mo. slack
ID
10
11
12
Task Name
Qtr 2
Electronics
Qtr 3
Qtr 4
2001
Qtr 1
Qtr 2
Qtr 3
Qtr 4
2002
Qtr 1
s
Design & fabricate electronics
Computer board
13
Design
14
Fabrication
15
Debug
s
72%
d
85%
gn
2/7
Fabrication
3/27
Debug
23%
16
UmbA (Old cam & DRV)
17
UmbB (New cam & DRV)
UmbB (New cam & DRV)
1/31
18
UmbC (Old cam & 6553)
UmbC (Old cam & 6553)
1/31
19
UmbD (New cam & 6553)
UmbD (New cam & 6553)
UmbA (Old cam & DRV)
20
Camera board
d
21
Design
gn
22
Fabrication
23
Debug
25
CamB (One quad)
26
CamC (4 quads)
28
Design
29
Fabrication
30
Debug
31
Modify test dewar
32
Test engineering detector
33
Fix problems
22 May 2001
2/14
45%
4/27
1/3
Debug
CamA (Emulate old cam)
Dewar cable
4/6
Fabrication
24
27
Qtr 2
0%
CamA (Emulate old cam)
1/17
CamB (One quad)
CamC (4 quads)
le
gn
1/31
2/14
58%
6/7
Fabrication
Debug
Modify test dewar
2/7
2/14
2/14
Test engineering detector
5/9
Fix problems
DR SOAR Spartan IR Camera
48
Optical Box, Enclosure, & Mechanisms
• Optical box & enclosure will soon be a critical task.
• Plans for mechanisms have changed.
– Swales Aerospace’s estimate is 3 times higher than that of 1998.
– New plan is to purchase high quality, warm stages & design nonprecision parts.
– Short slack.
Task Name
Qtr 2
Qtr 3
Design thermal concept
pt
5/29
Design mechanical concept
ept
6/7
Optical bench & enclosure
Qtr 4
2001
Qtr 1
Qtr 2
Drafting
Fabrication
Fabrication
Testing
Write specifications
Choose vendor
Detailed design
2002
Qtr 1
7/5
11/8
4/25
Mechanisms
te specifications
Qtr 2
0%
Testing
4%
12/15
Choose vendor
7/26
Detailed design
Fabrication & Testing
22 May 2001
Qtr 4
Optical bench & enclosure
Drafting
Mechanisms
Qtr 3
10/25
Fabrication & Testing
DR SOAR Spartan IR Camera
4/25
49
Optics
• Optics & filters are behind schedule.
– Estimated time is 2–3 times longer than vendors’ quotes of 26
weeks, because of word-of-mouth tales.
– Schedule could be made up with immediate requisitions and ontime deliveries
Task Name
Design optical details
Choose vendors
Fabricate optics
Qtr 3
etails
Qtr 4
2001
Qtr 1
Qtr 2
2/15
Choose vendors
Qtr 3
Fabricate optics
Fabricate filters
Write RFQ for telescope simulator
Write RFQ for telescope simulator
22 May 2001
2002
Qtr 1
Qtr 2
4/12
Fabricate filters
Fabricate telescope simulator
Qtr 4
Fabricate telescope simulator
DR SOAR Spartan IR Camera
4/25
10/25
4/25
50
Qtr 3
Software
• ArcView will be fully tested by CTIO with the Optical Imager.
• Scope of software task is uncertain.
– No experience with LabView.
– Need to see ArcView.
• If task is beyond students’ capability, we will seek vendor such
as Imaginetics.
Task Name
Software
Qtr 2
are
Write operating manual
nual
Design software
oftware
Write software
Test software
22 May 2001
Qtr 3
Qtr 4
2002
Qtr 1
Qtr 2
Qtr 3
Qtr 4
2003
Qtr 1
0%
6/21
8/16
rite software
2/28
Test software
DR SOAR Spartan IR Camera
5/23
51
Qtr 2
Integration & Installation
• There is a 16 week period for fixing problems.
• Delivery is scheduled for 3/28/03.
ID
62
Task Name
Qtr 2
Qtr 3
Qtr 4
2003
Qtr 1
Qtr 2
Integration
63
Integrate electronics & software
64
Install optics
65
System integration
66
Fix problems
67
Install science-grade detector
68
Instrument finished
69
Install on telescope
22 May 2001
Qtr 3
Qtr 4
0%
are
8/15
s
8/15
m integration
10/10
Fix problems
Install science-grade detector
1/30
2/27
Instrument finished
Install on telescope
DR SOAR Spartan IR Camera
2/28
5/8
52
2004
Qtr 1
Risk to Schedule
• Tasks on the critical path
– Optics are delayed.
– Optical box & enclosure have little slack.
– Mechanisms have a short slack.
• Delay of funding is the greatest risk.
– Without starting on the critical tasks, we cannot test our estimates.
We cannot set accurate bounds on the task.
22 May 2001
DR SOAR Spartan IR Camera
53