teoa m2 optical assembly fabrication - dkist · 2020-01-22 · l-3 communications proprietary jay...
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L-3 Communications Proprietary
Jay Schwartz 2/21/2012
TEOA M2 Optical Assembly
Fabrication
This technical data is controlled under the International Traffic in Arms Regulations (ITAR) and may not be exported to a Foreign
Person, either in the U.S. or abroad, without proper authorization by the U.S. Department of State.
ITAR Controlled Document
TEOA M2 Optical Assembly Fabrication Outline
M2 Optical Assembly Fabrication
– Manufacturing Overview
– Polishing Overview
M2 Optical Assembly Metrology
– Primary Optical Test Method
– Redundant Optical Test Method
– Profilometry Test Method
– Metrology Tolerance Analysis
– Metrology Setup Alignment
M2 Optical Assembly Shipping Plan
Preliminary Verification Matrix
Risk Summary & Mitigation Plan
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L-3 Communications Proprietary
M2 Optical Assembly Manufacturing
Jay Schwartz
Program Manager - SSG
3
M2 Optical Assembly Manufacturing Process Flow
4
Mirror Tooling
Design
Procure
Tooling Cast Mirror
Substrate Sintering
Furnace Run
Machine Sintered
Substrate
Full Density
Furnace Run
Final
Machining Ship to
Tinsley
Grind Unclad Optical
Surface (~1 micron of
profile)
Ship to Cladding
Vendor
Deposit Protected
Silver Reflective
Coating
Ship to
Tinsley
Post Coating
Metrology/FAT
Delivery to Brashear for
TEOA Integration
Procure Shipping Container
Optical Metrology
Bond
Bipods Thermal
Cycle
Procure Bipods and Transfer Plate
Ship to Silicon Cladding
Vendor Deposit Silicon
Cladding
Final Polish Optical
Surface
Ship to
Tinsley
Ship to
Coating
Vendor
M2 SiC Substrate Fabrication
5
L-3 Communications Proprietary
M2 Optical Assembly Polishing Overview
A. Magruder
2/21/2012
M2 Optical Assembly Polishing Overview-Tinsley
Computer controlled grind and polishing tools used in conjunction with metrology to
achieve overall surface figure, high spatial frequency figure and surface roughness.
Grind asphere to within ~1 micron P-V in bare SiC surface.
Final grind and polish performed in silicon cladding
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M2 Optical Assembly Polishing Methodology
To meet Encircled Energy Budget, Tinsley will polish M2
surface to a nominal 40 deg telescope zenith angle.
– Tinsley will polish to a software null surface figure that will be
provided from an finite element analysis model.
– Gravity Induced Mount Error caused ~ 40 nm of 3 theta
(trefoil) surface error at horizontal LOS.
– This predictable error can be removed using localized
polishing to a software null.
Tinsley has a history of polishing Spherical and Aspheric
mirrors to extreme precision utilizing Computer Controlled
Optical Surfacing (CCOS) to data provided through
interferometric null testing.
This capability has been applied to optical surfaces that
do not have convenient null test configurations through
the use of a software null.
To accomplish this, an optic is measured relative to a
reference wavefront that provides a near-null
interferogram. This interferogram is then compared to the
expected interferogram for the desired amorphous surface
in test.
8 2/15/2012
Example of desired departure from a null
interferogram
Example of null test setup
Software Null Example #1 JWST TM Software Null
9
In 2011, Tinsley completed the James Webb Space Telescope (JWST) beryllium Mirrors
and Mirror Segments. Each was tested and fabricated in an ambient environment with a
software null expected to yield a nominal prescription in a cryogenic environment.
The 0.7m JWST TM software null had a magnitude of 66nm RMS and an irregular
shape.
The desired mirror surface was replicated to within 5 nm RMS of the nominal figure and
this result was verified through testing in cryogenic conditions.
Surface map of desired surface figure error:
390nm P-V, 66nm RMS from aspheric
prescription
Departure from desired surface:
79nm P-V, 4.3 nm RMS
For aspheric mirrors with slight departure from best fit sphere, this technique can be
used to reduce the cost and lead time associated with diffractive elements or test optics.
The optic is tested against a spherical wavefront. The test results are compared to an
expected deviation and the resulting data is used to manufacture the desired asphere.
This technique was implemented on the below displayed convex hyperboloid with
147nm RMS departure from best fit sphere.
10
Synthetic Fringe map of desired surface figure
error: 535nm P-V, 147nm RMS from spherical
reference wavefront
Departure from desired surface over Clear
Aperture: 13.5nm P-V, 1.4 nm RMS
Software Null Example #2 Mild Asphere Departure
L-3 Communications Proprietary
M2 Optical Assembly Metrology
Adam Magruder
L-3 IOS Tinsley
11
M2 Metrology - Tinsley
L-3 IOS Tinsley plans to perform three measurements to verify prescription and
irregularity.
The optic will be tested
– (1) using a computer-generated hologram (CGH)
– (2) in a conjugate configuration
– (3) using profilometry
CGH testing allows the M2 Mirror to be easily sheared rotationally in gravity which is
attractive in that it allows measurement of the mount-induced surface distortion.
The aspheric departure of the M2 Mirror is relatively low and the CGH has a
relatively routine design. This will facilitate design and fabrication of the CGH and
reduces the effect of printing errors which improves the accuracy of the projected
wave front on the part. These residual errors are accounted for in our error budget.
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M2 Optical Prescription Parameters and Tolerances
The ATST M2 Mirror concave off-axis ellipsoid has the optical prescription
parameters indicated in Table below.
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Parameter Nominal Tolerance
Radius 2081.25885 mm ± 1mm
Off Axis Distance 594.312 mm ± 0.2mm
Clocking 0 ±1 Arc Minute
Surface Figure Error 0 25 nm RMS
M2 Primary Optical Test Method CGH Layout Design
The CGH test layout is shown below. The CGH is expected to be placed 315mm
from the Cat’s eye with the mirror located approximately 2.2m from the cat’s eye.
These spacings and alignments will be set using the CGH alignment features as
described in the Tolerance Analysis and Metrology Setup Alignment sections.
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The primary buyoff methods of profilometry and the CGH based interferometric test
will be complimented by conjugate testing of the M2 Mirror, with an interferometer at
the far catseye, and an Spherically Mounted Reflector (SMR) at the near catseye
(Figure 1). The two conjugates are located at approximately 1.2 and 7.8m,
respectively, from the M2 Mirror vertex. This test will be set up on a 20 x 5 foot
optical table with a fold flat to account for the full long conjugate length
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M2 Redundant Test Method Conjugate Testing
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Fold
Flat
M2
20x5 foot table Interferometer
The test beam is approximately F/11. Data will be collected first as a full aperture
measurement to quantify prescription and low order shape, and then the test beam
will be zoomed in to 4x, to interrogate ~Ø150mm subapertures to quantify mid
frequency surface figure. These measurements will measure M2 Mirror spatial
periods from 75mm down to approximately 1.2mm. Phase measuring microscopy
will be used to measure spatial periods from below 0.15mm to as long as 2.5mm,
providing validating overlap with the subaperture measurements of high spatial
frequency surface structure to verify the high spatial frequency surface figure
accuracy requirement.
M2 Redundant Test Method Conjugate Testing
A laser tracker will then be used to directly measure the positions of the long
conjugate, the short conjugate and the mirror alignment targets which will give the
Radius of curvature and Conic constant.
The Off Axis Distance and Clocking relative to the alignment targets will be
measured in the CGH based interferometric test as a secondary method. This will
use the alignment targets as retro reflectors that position the optic relative to the
CGH and cat’s eye
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M2 Redundant Test Method Conjugate Testing
Optical Testing Heritage JWST Tertiary – Conjugate Test
L-3 IOS Tinsley used a conjugate test to verify the optical prescription of the JWST
tertiary.
The far conjugate of the JWST tertiary mirror is located 16m from the mirror, forcing
the test setup to be folded to fit within available facility space.
The JWST tertiary conjugate test was designed as a prescription verification only
(radius, conic, OAD) and extra precautions were not taken to achieve the best
possible surface figure error accuracy.
Nevertheless, the conjugate test measurements achieved 15nm RMS agreement
with the CGH center of curvature test ,proving the value of these two independent
metrology approaches in cross-checking each other.
This agreement can be improved through calibration of the transmission sphere,
using an improved SMR at the short conjugate, and controlling air turbulence each of
which is described in the Tolerance Analysis section.
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Test Methodology Heritage to JWST Tertiary (1)
L-3 IOS Tinsley used the three optical test methods (CGH center of curvature,
conjugate testing, and optical profilometry) in 2010 to verify the surface figure
accuracy of the JWST tertiary mirror. The primary test method was CGH center of
curvature. L-3 IOS Tinsley delivered the JWST tertiary mirror with a surface error of
4.3 nm RMS.
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Optical Testing Heritage JWST Tertiary – Surface Error
Figure below shows the difference between CGH and Conjugate Testing of the
JWST Tertiary was < 15 nm RMS
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Optical Testing Heritage JWST Tertiary - CGH / Conjugate Test Comparison
M2 Profilometry Test Method Heritage JWST Tertiary
L-3 IOS Tinsley used profilometry to cross-check the optical prescription on the
JWST tertiary.
Our Profilometry measurements are accurate for low order shape with a 3σ
confidence to 490 nm P-V. This uncertainty is used to bound the potential errors in
OAD, Clocking, and Radius.
This analysis can be seen in the Tolerance Analysis section. The profilometers are
also accurate in mid frequency surface figure to 100 nm RMS as seen below in a
measurement of the JWST Tertiary Mirror.
Although this did not act as a fully redundant quantification of the RMS surface
figure error requirement, it did show that there were no major errors with the optical
tests.
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M2 Profilometry Test Method Heritage JWST Tertiary
Profilometry of the JWST tertiary mirror was repeatable to 100 nm RMS.
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L-3 Communications Proprietary
Adam Magruder
L-3 IOS Tinsley
M2 Optical Assembly
Metrology Tolerance Analysis
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M2 Optical Test Tolerance Overview
The key parameters for Tolerance Analysis for the ATST M2 Mirror are the radius of
curvature, the rotation relative to the M2 Assembly (clocking), the off axis distance,
and the surface figure error. The Table below summarizes the sensitivity of sag
error to variation of these key parameters within their tolerance band.
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Parameter Nominal Tolerance P-V Resulting Sag
Error
Radius 2081.25885 mm ± 1mm 11.16 μm
Off Axis Distance 594.312 mm ± 0.2mm 0.82 μm
Clocking 0 ±1 Arc Minute 0.70 μm
Surface Figure
Error 0 25 nm RMS
M2 CGH Test Method Tolerances
CGH Based Interferometry will serve as the primary buyoff method for surface figure
error and as a redundant method for Off Axis Distance and Clocking. This test uses
a CGH to modify a spherical wavefront to match the aspheric prescription of the
mirror. We will align the mirror in test to match the positions of the alignment targets
on the mirror to pencil beams that will be emitted from the CGH. These beams will
retro reflect off of the alignment targets, and produce fringes in the interferometer
which we will use to position the mirror in X and Y decenter as well as clocking to the
CGH. For the JWST TM this alignment method was sufficient to align the mirror to
0.33 arc minutes in clocking and 0.1 mm of centration, and similar uncertainty is
expected on the ATST M2. The Z position of the part will then be floated and
residual alignment aberrations are accounted for in our error budget. Figure 1 is our
initial error budget analysis for the surface figure error of the ATST M2.
Each error source is assigned a sensitivity which describes the effect of a
perturbation of this term on our knowledge of the optical surface and a tolerance
which bounds the size of the perturbation in test. The tolerances in this analysis are
based on as-measured tolerances from the JWST TM CGH test and will be re-
quantified for the ATST M2. The sensitivities are based on an initial design for the
ATST M2 by Diffraction International and will be updated when the final design is
complete.
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The conjugate test will also provide a secondary measurement of the Surface figure
error. This measurement will have errors associated with air turbulence over the
long path length, errors in the surface of the retro ball placed at the short conjugate,
and errors in the transmission sphere on the interferometer.
Great care is taken to reduce the air turbulence and thermal gradients by performing
the measurements in our large optics metrology lab equipped with a constant
unidirectional air flow. This serves to keep air moving through the test which
prevents pockets of heat from forming and disrupting the measurement. Since
Tinsley is operational 24 hours per day the final tests can be set up to run through
during the night shifts which additionally reduces turbulence and thermal variations.
For the Retro Ball at the short conjugate, we will use a ruby ball coated in silver to
provide a high precision optical surface. These balls are spherical to within ~60nm
P-V which is typically due to surface defects on the ball. The specific ball to be used
will be measured and quantified for the Conjugate test Error budget. This will not
contribute significantly to the 25nm RMS specification.
Transmission sphere will be calibrated and subtracted using a shearing algorithm
and a calibration sphere.
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M2 Conjugate Test Method Tolerances
M2 Profilometry Test Method Tolerances
The primary buyoff method for Radius, Off Axis Distance, and Clocking will be with
the Leitz PMM_C Profilometer.
Well designed profilometry fixtures which allow for repeatable and stable placements
of our test optics.
Careful calibrations and analysis to remove errors due to thermal drift and spurious
data points allow very precise measurements of optical prescription on our Leitz
PMM_C profilometer.
Gravity deflection and thermal gradients are also important considerations in
characterization of prescription, and can be calculated and compensated for if
necessary.
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Table shows repeated measurements of a
concave sphere of radius 1757.127mm
and diameter 620mm. The Sphere is
measured using an interferometer with a
DMI, and is measured with the Leitz
PMM_C. The radius is compared to find
the uncertainty of the profilometer for low
order shape. Out of 15 measurements
the maximum Radius discrepancy is .0209
mm which translates to a sag error of
333nm P-V using the sag equation of a
sphere.
The 99% confidence deviation is the
average deviation plus 3σ, .002 mm +
3*.0096mm.
This yields a three sigma confidence of
0.0308mm or 490nm P-V.
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Measurement
File Name
DMI
MEASURED
Radius of
Sphere
Leitz PMM,
Measured
Radius (mm) Delta (mm)
Average of
Group
Average
Delta of
Group
PRBRUN1 1757.127 1757.1235 0.0035
PRBRUN2 1757.127 1757.1198 0.0072
PRBRUN3 1757.127 1757.1261 0.0009 1757.1231 0.0039
XMRUN1 1757.127 1757.1183 0.0087
XMRUN2 1757.127 1757.1061 0.0209
XMRUN3 1757.127 1757.1231 0.0039 1757.1159 0.0111
XPRUN1 1757.127 1757.1257 0.0013
XPRUN2 1757.127 1757.1141 0.0129
XPRUN3 1757.127 1757.1477 -0.0207 1757.1292 -0.0022
YPRUN1 1757.127 1757.1225 0.0045
YPRUN2 1757.127 1757.1341 -0.0071
YPRUN3 1757.127 1757.1329 -0.0059 1757.1298 -0.0028
YMRUN1 1757.127 1757.1329 -0.0059
YMRUN2 1757.127 1757.1248 0.0022
YMRUN3 1757.127 1757.1233 0.0037 1757.1270 0.0000
Average 1757.1250 0.0043
Standard Deviation 0.0096 0.0113 Range, %
Maximum 1757.1477 0.0209 0.0012%
Minumum 1757.1061 -0.0207 -0.0012%
Table: Profilometry repeatability and accuracy
This is considered to be the uncertainty in low order figure in our profilometer
and is applied to deviations in Radius, Off Axis Distance, and Clocking for the
ATST M2
M2 Profilometry Test Method Tolerances
M2 CGH Test Method Tolerances
This analysis of surface figure error
shows a total potential error of 5.85
nm RMS. This is removed in
quadrature from the total tolerance
of 25nm RMS to leave a part
fabrication residual of 24.3 nm
RMS. This means that when these
tolerances are met and we measure
a final value less than 24.3 nm
RMS, we will have confidence that
the true value is below 25nm.
In order to meet these tolerances a
careful fine alignment of the
interferometer, CGH, and part under
test is needed. The equipment and
methods used for this alignment are
described in the Metrology Setup
Alignment plans section.
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# meas Tolerance unit
Tinsley Specification
Fixed Metrology
Metrology (Estimated)
Optical design residual 1 fringes
CGH Fabrication
Substrate Thickness 1 0.08 mm 0.22
Substrate Index 1 0.0001 0.00
Substrate Wedge TLA 1 0.10 frg 0.03
Substrate Wedge TLB 1 0.10 frg 0.02
Substrate Power 1 0.14 frg 0.91
E-beam Registration 1 0.07 um 0.70
Substrate TWF 1 4.75 nm 2.06
Encoding and Digitization 1 0.05 frg 0.49
Test Alignment
Cat's Eye X 1 0.002 mm 0.142456
Cat's Eye Y 1 0.002 mm 0.22223
Cat's Eye Z 1 0.02 mm 0.711769
Horizontal Fringes 8 3.00 frg 0.112424
Vertical Fringes 8 3.00 frg 0.072152
Power Fringes 8 1.00 frg 2.265028
Part asphere R 1 0.30 mm 3.609239
Interferometer
Source Zernike #1 1 2.50 wv 0
Source Zernike #2 1 2.50 wv 0
Source Zernike #3 1 5.00 wv 0.03164
Source Zernike #4 1 1.00 wv 0
Source Zernike #5 1 1.00 wv 0
Source Zernike #6 1 1.00 wv 0.003164
Source Zernike #7 1 1.00 wv 0.003164
Source Zernike #8 1 1.00 wv 0.022148
transmission sphere irregularity 8 1.00 0.542552
Wavelength 1 0.01 nm 1.273194
Data Processing
Data Registration fid loc 1 1.00 test 0.143402
CGH Null scale 1 0.01 N.A. 0.377534
CGH Null decenter X 1 0.01 Ø 0.272732
CGH Null decenter Y 1 0.01 Ø 0.464594
CGH Null clocking 1 0.60 deg 0.121306
Metrology Reserve
Thermal Stability
Axial Gradient 1 0.03 K
Horizontal Gradient 1 0.10 K
Vertical Gradient 1 0.10 K
Thermal Soak 1 2.20 K
Part Fabrication Residual
0
2.487483945
0.684135204
24.3054745
0.674476249
0.474369081
1.818248431
1.620519398
1.901122366
0
1.384520165
4.330254288
RMS Surf Error (nm)
4.97496789
5.851829564
25
M2 Conjugate Test Method Tolerances
The conjugate test will serve as the redundant buyoff method for Surface Figure
Error, Radius of Curvature, and Conic Constant. In this test the interferometer, part
under test, and a retro reflecting tooling ball will be placed on a 20x5 foot table with a
fold flat to account for the full long conjugate length. They will be aligned to best null
and a laser tracker will be used to measure the spacing between an SMR placed at
Cat’s eye, the parent vertex of the part through the alignment datums, and an SMR
placed at the short conjugate. This spacing will be reported along with the residual
measured wave front to show the Conic Constant, Radius of Curvature, and Surface
Figure Error.
In order to ensure that the Radius and Conic fall within 1mm of nominal Radius and
the associated shift in conic through, the short conjugate must be known with an
accuracy of .7mm and the long conjugate must be known with an accuracy of
1.435mm as seen below in figure 2. These uncertainties are large relative to the
abilities of the laser tracker and should not represent a technical challenge. For the
JWST TM, a similar conjugate test was performed. The uncertainties in the
measured conjugate locations for that test were .035mm for the long conjugate and
.018mm for the short conjugate. The agreement between this test and our primary
methods for measuring Radius and Conic were .057mm and .00012 respectively,
which would be well in the range of the ATST M2 allowed tolerances.
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1.201 103
1.2006 103
1.2002 103
1.1998 103
1.1994 103
1.199 103
7.822 103
7.824 103
7.826 103
7.828 103
7.83 103
7.832 103
7.834 103
7.836 103
7.838 103
7.84 103
7.842 103
Conjugate Sensitivity
f2 (mm)
f1 (
mm
)
d2 R Rerror K Kerror d2 R Rerror K Kerror
20.699 mm
d1 R Rerror K Kerror d1 R Rerror K Kerror
21.435 mm
M2 Conjugate Test Method Sensitivity
L-3 Communications Proprietary
Adam Magruder
L-3 IOS Tinsley
M2 Optical Assembly
Metrology Setup Alignment
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M2 Metrology Setup Mechanical Equipment
In order to meet the tolerances laid
out in our error budget, a careful fine
alignment of the interferometer,
CGH, and part under test is needed.
Tinsley’s unique 5-axis mount, as
seen in figure 1, allows sub micron
adjustments in X, Y, and Z,
translation as well as sub micro
radian adjustments in rotation about
the X and Y axes.
The CGH will also be mounted in a
fine pitched 5 axis mount, which will
allow the error budget required 2µm
of placement accuracy of the cat’s
eye relative to the other optical
components.
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Figure shows a 620mm OD Round concave optic
mounted on Tinsley’s 5-axis mount.
M2 Metrology Setup CGH Alignment
The CGH is first set to be normal to the interferometer’s outgoing beam by centering
the reflection of a collimated source off of it’s front surface on the alignment camera.
Then the transmission sphere is installed and the holograms designed into the CGH
are used for subsequent alignment.
The CGH is designed with three separate hologram patterns. The main central
hologram will hold the prescription of the asphere. This will bend the incoming
spherical wave front so that each ray contacts the surface of the M2 at normal
incidence.
A second hologram pattern is built into the exterior portion of the CGH that will give a
null return when the CGH is properly placed with respect to the cat’s eye to confirm
that this alignment tolerance is not exceeded. Since there fringes returned to the
interferometer this can be aligned to sub micron accuracy in x, y, and z centration.
A third set of holograms will create three pencil beams just outside the aperture of
the optic. These beams will converge on the alignment targets attached to the optic
and, when properly aligned, will return fringes to the interferometer which sets the X
and Y centration and clocking of the optic relative to the CGH and cat’s eye.
Finally, since the radius of curvature is controlled with the profilometer and conjugate
test, the optic is adjusted in Z translation to null out power fringes. This type of CGH
design was used on the JWST Tertiary Mirror, and has proven itself to accurately
place the CGH and Mirror relative to cat’s eye within budgeted alignment tolerances.
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M2 Metrology Setup Conjugate Alignment
For the Conjugate null test the part will be similarly loaded onto our 5-axis mount on
a 20x5 foot table.
A fold flat can be used to accommodate the extra distance to the long conjugate
location.
An SMR will be placed at the short conjugate location and the mirror and short
conjugate SMR will be adjusted in X, Y, and Z decenter as well as clocking and tilt to
achieve the best null.
A laser tracker will then be used to measure the relative positions of the long and
short conjugates, and the alignment targets on the mirror.
These measurements will quantify the Conic, Radius of curvature, and residual
surface figure error within the allotted specifications. See the Tolerance Analysis
section for a further discussion of allowed alignment tolerances.
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M2 Optical Assembly Shipping Plan
M2 Optical Assembly will be bolted to the
Strong Back.
The Strong Back will be mounted to a
Shipping Plate.
The Shipping Plate will be bolted to
vibration isolators attached to inside of
Pelican AL3434-1207 Single Lid Case
Pelican case will be shipped inside a
wooden shipping container with custom
foam inserts.
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Preliminary Verification Matrix (1)
Paragraph Heading Specification Value Verification Method Compliance Comments
3.1.1.1 Clear Aperture CA = 620 mm I Y
3.1.1.2 Surface Figure Accuracy 24 nm RMS (tip, tilt, piston and focus (per Sandy) removed) T Y
3.1.1.3 Surface Figure Accuracy, Higher Spatial Frequency Error
6.9 nm RMS for spatial period from 0.15 mm to 15 mm T Y
3.1.1.4 Surface Imperfections
no surface imperfections of surface area larger than 5.0 square millimeters shall be allowed, and a maximum of 10.0 square millimeters shall be allowed for the summation of all defective areas within the Optical Surface T Y
3.1.1.5 Surface Roughness Less than 20 angstroms RMS (Goal less than 10 angstroms RMS) T Y
3.1.1.6 Optical Coating Brashear I A,T A,T A,T Y Brashear
3.1.2 Physical Charcteristics Drawing 164350 A I T T T T Y Drawing 164350
3.1.2.1 Alignment Targets
The accuracy in position of the target interfaces shall be within 100 microns of their reported position relative to the measured Optical Surface geometry. A,T Y
3.2.1 Interface identification and diagrams TBD ICD Y TBD ICD
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Preliminary Verification Matrix (2)
Paragraph Heading Specification Value Verification Method Compliance Comments
3.3 System Environment Requirements I A
3.3.1 Operating A Y
3.3.1.1 Temperature -2 deg C to 22 deg C and a temperature change rate of +/- 2 deg C/hr maximum. A Y
3.3.1.2 Optical Surface Temperature Brashear Y Brashear
3.3.1.3 Humidity 0 to 70 percent relative humidity A Y
3.3.1.4 Wind Load wind speeds of up to 5 m/s (11 mph) from any direction. Y
3.3.1.5 Gravity Orientation Brashear Y Brashear
3.3.2 Non-operating A
3.3.2.1 Temperature
temperature range of -10 deg C to 27 deg C (14 deg to 81 deg F) and a temperature change rate of +/- 2 deg C/hr maximum. A Y
3.3.2.2 Humidity 0 to 95 percent relative humidity A Y
3.3.2.3 Equivalent Static Load 3 g acceleration in any direction A Y
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Preliminary Verification Matrix (3)
Paragraph Heading Specification Value Verification Method Compliance Comments
3.3.3 Transportation Environment A Y
3.3.3.1 Altitude Range sea level to 4500 meter A Y
3.3.3.2 Temperature -20 deg to +50 deg C. A Y
3.3.3.3 Humidity 0 to 100 percent relative humidity. A Y
3.3.3.4 Wind Speed up to 70 m/s from any direction. A Y
3.3.3.5 Shock and Vibration 10 g acceleration in any direction A Y
3.4.1 Structural Design Requirements Factor of Safety of 4.0 A, I
3.4.2 Drawings and Document Requirements conform to AMSE Y14.5M-2009 I Y
3.4.3 Materials and Workmanship Requirements I Y
3.4.4 Stress Relieving Requirements I Y
3.4.5 Surface Finish, Coatings and Paint Requirements surface finish of 64-microinches or better I Y
3.4.6 Grounding I Y
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Preliminary Verification Matrix (4)
Paragraph Heading Specification Value Verification Method Compliance Comments
3.4.7 Labeling Drawing 164350 I Y
3.4.8 Metrology, Inspections, and Factory Test Requirements
calibrated and traceable to established standards I Y
3.4.9 Reliability and Lifetime Requirements Lifetime of 40 years A A A Y
3.5.1.1 M2 Transport Container To and from coating vendor per 3.3.2 and 3.3.3 A,I Y
3.5.2.1 M2 Transfer Interface Plate ICD TBD I Y ICD TBD
3.5.2.2 Protective Cover Brashear A,I Brashear
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Risk Assessment
Technical
– Fabrication of substrate-Low Risk
• Similar sized SiC have been fabricated (ABI scan mirrors)
• Internal R&D has demonstrated techniques and processes for 650 mm substrate
• Established machining vendor base
– Bonding of Bipods-Low Risk
• Process has been demonstrated for multiple SiC programs
– Silicon Cladding-Low Risk
• Vendor base established and demonstrated on multiple SiC programs
• Detailed process in place for tooling, surface preparation, deposition of silicon and
inspection
• Risk similar to complex optical coating risk
– Grind and Polish of optical surface-Low Risk
• Tinsley has significant heritage with silicon clad, SiC aspheres
– Reflective Coating-Low Risk
• FSS99 baseline coating has heritage to multiple flight programs
Schedule
– Long Lead items for substrate fabrication-suggest placing tooling orders as soon as possible
ITAR Controlled Document