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NHST design issues
R. A. Woodruff
robert.a.woodruff@lmco.com (303) 918-5639 Lockheed Martin 4/10/03

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

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Candidate mission options for NHST
Ultraviolet Imaging Visible Coronagraphy Very-wide FOV visible imaging Ultra-wide FOV visible imaging
· Each is a large telescope with precise and stable system wavefront control
­ Large mirrors, structure, system ­ All require sensing and controlling of WFE

· Basic designs are similar · Complementary design issues · Technology needs are similar
NHST symposium at STScI, 4/10/03 © 2003 Lockheed Martin Corporation. All rights reserved.

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Typical requirements
(1 of 2)

· Visible coronagraphy, Planet Detection
­ Wavelength range: 500 ­ 1000 nm ­ D(m) /FOV(0) /IFOV(mas) /f(m):

· Ultraviolet Imaging
­ Wavelength range · 100 to 300/1000 nm ­ D (m) /FOV (0) /IFOV (mas) /f(m): FPA · f/8: 4 x 10 m/ 300 0/ 30 mas/ 80 m:10K x 10K [uv.1 (offaxis), uv.2 (on-axis)] · f/150: 4 x 10 m/ 25 0/ 4 mas/ 620 m: 6K x 6K [uv.3]

FPA

­

­ X-FOV 12 to 24 arc minutes for other science
­ ­ ­ ­ WFE: 7 nm rms: D.L. at 100 nm. Minimize number of mirrors Solar blind detectors Contamination control

­ ­ ­ ­

· f/40: 4 m/ 1.9 0/ 15 mas/165 m: 128 x 128 · f/50: 4 x 10 m/ 3 0/ 5 mas/ 495 m: 600 x 600 [tpf.1] Contrast of 1010 @ 4 /D [50 to 100 mas] ­ WFE: < 150 pm rms {CSFR, 3 to 60 cpa}, 2 nm rms LSFR More mirrors allowed, but be careful Real pupil images ­ Apodizer, Lyot Stop WFE corrected field image Very low noise, high QE detectors with low red-leak
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NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.


Typical requirements
­ Wavelength range: 350-1000 nm ­ D (m)/FOV (0)/IFOV (mas)/f(m): FPA · f/120:4 m/ 480 0/ 5 mas/ 500 m: 96 K x 96 K [9 G-pixels] ­ WFE
· 14 nm rms · D.L. at 200 nm.

(2 of 2)

· Very-wide FOV Imaging · Ultra-wide FOV Imaging

­ More mirrors allowed than UV ­ Low noise, high QE detectors with low red-leak

­ Wavelength range: 350 ­ 1000 nm ­ D (m)/FOV (0)/IFOV (mas): FPA · f/6: 4 m plus/ 600 0/ 100 mas: 6 K x 6 K [4 M-pixels] · f/6: 4 m plus/ 3600 0/ 100 mas: 1 sq. degree [1.3 Gpixels], uwfov.1 ­ FOV/IFOV: 100 square arc minutes to few square arc degrees/ 100 mas ­ WFE: 36 nm rms: D.L. at 1000 nm. ­ More mirrors allowed than UV ­ Low noise, high QE detectors with low red-leak ­ Examples: SNAP and UWFI
4

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.


Complementary requirements
D (m)
cs

# of ( mirrors

WFE WFE overall PM cs) (nm rms) (nm rms)

Corrected WFE, CSFR (pm rms)

WFS

WFC Passive or adaptive, PM support, SM 5 DoF Passive or adaptive, PM support, SM 5 DoF Passive or adaptive, PM support, SM 5 DoF

Very WFOV TMA Ultra WFOV

RC + relay

4+

200 nm

4 to 6

0.9

14

3

NA

Focus, THO, LSFR

4+

1000 nm

4 to 6

0.9

36

14

NA

Focus, THO, LSFR

UV imager

4 x 10 100 nm

3 to 4

0.4 to 0.5

7

2

NA

Focus, THO, LSFR

Coronagraph (Off-axis aperture)

TC + 4 x 10 TM + 500 nm or 4 relay

7

0.85

2, corrected

2

20 - 50

Active: DM. Focus, Adaptive: SM 5 THO, DoF, PM, LSFR, support, LOS CSFR jitter, Body point.

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

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Resultant design forms: TMA, Ritchey Chretien, True Cassegrain+Relay
· Ultraviolet Imaging
­ Two mirror RC or TMA ­ Passive WFC ­ Force actuators on PM (and SM?) ­ Precision figured optics ­ Precision alignment: structural and thermal ­ Enhanced Al coating ­ Low red leak filters ­ Large photon counting FPA

· Very/Ultra-wide FOV Imaging
­ Ultra-wide FOV: TMA or RC + all reflective corrector ­ Very WFOV TMA ­ Standard "HST-like" WFE control ­ Passive WFC ­ Protected Ag coating ­ Extremely large FPA. Large radiator to cool arrays.

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

6


Typical TMA design: UV Imager. [uv.1] 300 arc sec camera.
Total FOV available for science package: 300 arc sec by 24 arc min

2747.25 MM

4 x 10 m NHS T, 3/03

Scale:

0.0091 raw

20-Mar-03

961.54

MM

1250.00 MM

4 x 10 m NHS T, 3/03

Scale:

0.03

raw

20-Mar-03

4 x 10 m NHS T, 3/03

Scale:

0.02

raw

20-Mar-03

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

7


Typical TMA design: UV Imager. [uv.2] 300 arc sec camera.
Total FOV available for science package: 300 arc sec by 24 arc min

1470.59 MM

4 x 10 m NHST,3 0 mas pixel, 3/ 03

Scale:

0.02

ra w

21-Mar- 03

337.84

MM

373.13

MM

4 x 10 m NHST,3 0 mas pixel, 3/ 03

Scale:

0.07

ra w

21-Mar- 03

4 x 10 m NHST,3 0 mas pixel, 3/ 03

Scale:

0.07

ra w

21-Mar- 03

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

8


Typical TMA design:
UV Imager. [uv.3] 25 arc sec camera with 4 mas pixels. Total FOV available for science package: 25 arc sec by 12 arc min

1923.08 MM

4 x 10 NHST, 4 mas c 25 arc sec FOV,3/ 03

Scale:

0.01

ra w

21-Mar- 03

2272.73 MM

543.48

MM

4 x 10 NHST, 4 mas c 25 arc sec FOV,3/ 03

Scale:

0.01

ra w

21-Mar- 03

4 x 10 NHST, 4 mas c 25 arc sec FOV,3/ 03

Scale:

0.05

ra w

21-Mar- 03

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

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Ultra WFOV TMA Like SNAP 1 square degree with 100 mas pixels. (uwfov.1)
833.333 MM

4 m dia. NH ST,1 squa re degree,100 mas p

Scale:

0.03

ra w

21-Mar- 03

925.93

MM

581.40

MM

4 m dia. NH ST,1 squa re degree,100 mas p

Scale:

0.03

ra w

21-Mar- 03

4 m dia. NH ST,1 squa re degree,100 mas p

Scale:

0.04

ra w

21-Mar- 03

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

10


Ultra WFOV with Ritchey Chretien
800.00 MM

HU FI , 90 squ are arc m in

raw

20-Mar-03

(90 square arc minute FOV with RC telescope + relay)

208.33

MM

156.25

MM

HU FI , 90 squ are arc m in

Scale:

0.12

raw

20-Mar-03

HU FI , 90 squ are arc m in

Scale:

0.16

raw

20-Mar-03

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

11


· Visible coronagraphy

Resultant design forms

­ Pupil control important ­ True Cassegrain + Tertiary Mirror
· Real pupil + field image

­ ­ ­ ­ ­

Off-axis aperture Force actuators on PM (and SM) Precision figured optics Precision alignment: structural and thermal Wavefront Sensing and Control
· Active CSFR WFS&C · Active (or adaptive) LSFR WFC&C · LOS jitter control and body pointing

­ Protected Ag or Au ( > 600 nm) coating ­ Filters with low red-leak ­ Small FPA: photon counting ideal, sub electron read noise

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

12


Typical visible Lyot coronagraph design
2500.00 MM

4 x 10 m Lyot Coronag raph, 3/ 13 /03

Scale:

0.01

ra w

04-Apr- 03

Coronagraph sensor FSM
2500.00 MM

4 x 10 m Lyot Coronag raph, 3/ 13 /03

Scale:

0.01

ra w

04-Apr- 03

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

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Detector DM, Pupil FSM Camera mirror

568.18

MM

XZ

4 x 10 m Lyot Coronag raph, 3/ 13 /03

Scale:

0.04

ra w

04-Apr- 03

Lyot stop, Aperture stop. Detector
4 x 10 m Lyot Coronag raph, 3/ 13 /03
Scale: 0.05

480.77

MM

raw

04-Apr-03

Corrected field/field mask
96.15 MM XZ

4 x 10 m Lyot Coronag raph, 3/ 13 /03

Scale:

0.26

raw

04-Apr-03

Coronagraph design: pupils and fields
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NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.


Technology Demonstration Mirror (JPL), PSD (Angstrom-cm2)
WFE at N CPA ends up in image at N Airy radii:

CSFR range is most critical to coronagraph
6 1 .10 6 10 5 1 .10 4 1 .10 PSD( k , Aspec ) 3 PSD( k , Agoal) 1 .10

k k

100 10

k 1 0.1

LSFR

CSFR M/HSFR
0.1 k , k , kfreq2 , kfreq3 , kfreq4
© 2003 Lockheed Martin Corporation. All rights reserved.

.01 0.01 0.01 .01
NHST symposium at STScI, 4/10/03

1

10 10

15


1200 1000 800
r (mas) r (in) r (out) r(out), 192

600 400 200 0 0 200 400 600 800 1000
0.350
CSFR WFE, nm rms, corrected
Aperture diam eter (cm )

Typical parameters for visible coronagraph (=600 nm) Increase DM actuator count to relax WFE
1.00E-09 1.00E-10 1E-09, 192 1E-10, 192

0.300 0.250 0.200 0.150 0.100 0.050 0.000 0 200 400

3 DM width CPA need r(out) (mas) Range r (AU) /D (mas) r(in) (mas) (actuators) 1000 5 pc 5 68.75 275.02 43.6 14.5 600 5 pc 3 30.94 123.76 58.2 19.4 300 10 pc 3 12.38 49.50 72.7 24.2 500 10 pc 5 12.38 49.50 121.2 40.4

4

600

800

1000

Ap e r tur e d iameter (cm)

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

16


Suitable combinations
· Not combinable
­ UV imager with VWFOV or UWFOV {System trades would allow combination with some loss of UV throughout}
· Minimize number of mirrors

­ VWFOV with UWFOV

· Combinable
­ UV imager + visible coronagraph ­ VWFOV + visible coronagraph ­ UWFOV + visible coronagraph
NHST symposium at STScI, 4/10/03 © 2003 Lockheed Martin Corporation. All rights reserved.

17


Properties of combined approaches
· UV, Very Wide or Ultra wide field imager would be TMA · Coronagraph has small FOV
­ Use of PM and TM of TMA ­ Pick-off FOV: Fold beam with FSM to coronagraph dedicated TM
· Uncorrected image at Cassegrain focus · Forms real pupil for DM and corrected field image at CFO
NHST symposium at STScI, 4/10/03 © 2003 Lockheed Martin Corporation. All rights reserved.

18


Design issues
·WFE · Size ­Mirrors · DM size ­Sensing, correction, stability · High QE, low noise ­Pupil shear detectors ­T gradients and level · FPA cooling in mirrors ­Alignment · Contamination ·Structural control ·Thermal
NHST symposium at STScI, 4/10/03 © 2003 Lockheed Martin Corporation. All rights reserved.

19


Technology categories
· · Large mirrors and structures Precise and stable WFE
­ ­ ­ ­ CSFR and overall Components Surface and coatings System Active and adaptive CSFR and LSFR Phase and amplitude LOS jitter and body point Deformable mirrors Pupil shear

· ·

UV enhanced coatings Precision components
­ Field mask ­ Apodizer

·

Low noise FPA
­ High QE ­ Large arrays ­ Solar blind UV

·

WFS&C
­ ­ ­ ­ ­ ­

·

Cooling large arrays
­ Annealing ­ Contamination control

· ·

Filters w/o red leak Stray light control

· · ·

Calibration System test Requirement flow-down modeling
20

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.


Commonality of critical technologies
DL Array Mwavelength pixels System WFE (nm rms) System M/CSFR WFE (nm rms) Structure PM WFE Structure T T lateral (nm rms) axial (K) (K) 7 7 2 2 3 1 0.1 0.07 0.02 Y SM (microns) PM T (K) DM T (K) Specific features UV Imager UV Imager UV Imager 500 nm 500 nm 100 nm 100 100 40 36 36 7 2 2 0.7 1 1 0.3 LSFR and CSFR WFS&C, Precise T control and alignment stability Ultra-large FPA/ cooling Very large UV FPA Very large UV FPA

Coronagraph

500 nm

1

2

0.02 to 0.05, 3 to 60 cpa

2

2

0.07

0.5

0.1

0.003

Ultra WFOV

1000 nm

1300

36

14

2

0.2

1 Adaptive LSFR WFS&C: Coma, astigmatism

2

Common features

Precision components, LSFR WFS&C

Scale up JPL T MD mirror

Orbit, Adaptive good LSFR WFS&C, thermal Focus control

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

21


Candidate mission options for NHST
Ultraviolet Imaging Visible Coronagraphy Very-wide FOV visible imaging Ultra-wide FOV visible imaging
· As on HST, other science instrumentation would share the corrected field
­ Spectroscopy, astrometry, photometry, etc.

· ·

Capability can be implemented to accomplish most desirable science Parallel, coordinated design studies and technology development can support multiple potential capabilities

NHST symposium at STScI, 4/10/03

© 2003 Lockheed Martin Corporation. All rights reserved.

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