Catania 28 Feb – 01 Mar 2011

V.Viotto (INAF - Osservatorio Astronomico di Padova)

TOU BreadboardStatus and Test

General strategy for the AIV during Definition Phase

2 roadmaps have been followed to prove the AIV feasibility of the 32 telescopes:

1. INDUSTRY1. Paper study on the aspherical lens feasibility2. Paper study on the aspherical lenses procurement feasibility fitting our time

schedule3. Paper study on the spherical lenses procurement feasibility fitting our time

schedule4. Paper study on the albemet structures procurement feasibility fitting our time

schedule5. Paper study on the N-TOUs AIV feasibility fitting our time schedule

2. RESEARCH INSTITUTES1. Identify an AIV concept and procedure, defined in agreement with the industry2. Test on a TOU PRE-BreadBoard of the AIV procedure3. Test on the TOU BB of the warm/cold system performance, defined and

performed together with the industry4. Test on CaF2 blanks (vibration and thermal cycling)

TOU Alignment Concept

By using Airy and Newton rings both of the back reflected and of the By using Airy and Newton rings both of the back reflected and of the transmittedtransmitted

light (introducing one lens at a time) the alignment will be performed.light (introducing one lens at a time) the alignment will be performed.

In order to maximize fringes contrast and airy rings visibility:In order to maximize fringes contrast and airy rings visibility:1.1. the CCDs are mounted on linear stages which can move along the optical the CCDs are mounted on linear stages which can move along the optical

axisaxis2.2. light shields can be inserted between each lens, to isolate the back light shields can be inserted between each lens, to isolate the back

reflected light, when needed, coming only from that lensreflected light, when needed, coming only from that lens3.3. A variable diameter iris is inserted on the collimated beam, to maximize A variable diameter iris is inserted on the collimated beam, to maximize

the transmitted and back-reflected spot visibilitythe transmitted and back-reflected spot visibility

Laser

Beam Expander

Variable Iris

B/S

Back Reflected Light

Transmitted Light

FocussingCCD

FocussingCCD

Telescope

Laser

Beam Expander

Variable Iris

B/S

Back Reflected Light

Transmitted Light

Focussing CCD

FocussingCCD

TOU

TOU Alignment Set-Up: Vertical

To allow lenses insertionfrom the top, the finalalignment set-up for theBB will be vertical

Strategy for the Breadboard alignment

1. PRE-BreadBoard: LENSES: identification of commercial lenses with, as much as

possible, the same curvature of the final design lenses MECHANICS: commercial off-the -shelf mechanics AIM: to test the alignment procedure and learn from the test setup

▪ Airy and Newton rings visibility▪ decenter and tilt misalignment sensitivity▪ tuning of the test setup components, e.g. the movement range of the

detectors

2. BreadBoard: LENSES: set of lenses as close as possible to the final design

lenses, differing only for the glasses and for the usage of a spherical lens instead of the aspherical one

MECHANICS: realization of an “equivalent mechanical structure” (in term of thermal behavior and interface with FPA)

AIM: to perform the real TOU alignment procedure to validate in cold conditions the warm AIV check of the interface between FPA and TOU (under system group

responsibility)

TOU Pre-BreadBoard

Laser

Beam Expander

Variable Iris

B/S

Back Reflected Light

Transmitted LightFocussingCCD #1

FocussingCCD #2

AIV constraint: in the final system, L3 is on the pupil of the system AIV constraint: in the final system, L3 is on the pupil of the system and its mount connot be adjusted in tip-tilt and centeringand its mount connot be adjusted in tip-tilt and centering. .

First AIV step will be to align the laser beam to L3, which will be First AIV step will be to align the laser beam to L3, which will be the first lens to be mountedthe first lens to be mounted

Because of that, you need to rotate the TOU breadboard Because of that, you need to rotate the TOU breadboard accordingly to which lens you’re aligning, to see its back-reflected accordingly to which lens you’re aligning, to see its back-reflected spots…spots…

Laser

Beam Expander

Variable Iris

CCD#1

CCD#2

PLATOSIMULATOR

ChannelA

ChannelB

2 channels have been realized to 2 channels have been realized to simulate the TOU 180º rotation simulate the TOU 180º rotation

during AIVduring AIV

XYZ stages

Tip-tilt

mounts

TOU Pre-BreadBoard

Laser

Beam Expander

Variable Iris

CCD#1

CCD#2

ChannelA

Channel A: Channel A: CCD#1 - reflected lightCCD#1 - reflected lightCCD#2 - transmitted lightCCD#2 - transmitted light

TOU Pre-BreadBoard-Channel A

Laser

Beam Expander

Variable Iris

CCD#1

CCD#2

ChannelB

Channel A: Channel A: CCD#1 - transmitted lightCCD#1 - transmitted lightCCD#2 - reflected lightCCD#2 - reflected light

TOU Pre-BreadBoard-Channel B

TOU Pre-BreadBoard – Status

Test are still on going, also waiting for the final alignment tolerances, but

some points seem to be already clear:

2 back reflected Airy rings systems are visible for each lens Newton rings systems are visible for each lens Transmitted spot can always be used Centering sensitivity is always below 50μm (the precision is

higher for the first lenses integrated -> L3) Tip-tilt sensitivity is always below 50 arcsec

These results have been obtained inserting lenses with the following

sequence:L3-L2-L1-L4-L5-L6

Detectors have always been moved in a range shorter than 400mm

Frame connected to the bench, allowing the

rotation for lenses insertion from the top and their

alignment similarly to what would happen with the final

structure, withthe possibility to be

rotated of 180º to insertthe lenses from both sides

(L3 will be the first one)

TOU BreadBoard

Laser

Beam Expander

Variable Iris

B/S

Back Reflected Light

Transmitted Light

Focussing CCD

FocussingCCD

Rotating points

TOU Dummy Structure

Fixing points

Breadboard AIV tools

1. Light shields between each couple of lenses (TOU) TBD after pre-breadboard

2. Tools for lenses insertion (TOU&Dummy) Each lens mount will have three threaded holes (120deg separated), insertion will be performed thanks to 3 long threaded bars

3. Tools for lenses centering during alignment (TOU&Dummy) 4 screws (2 of them with springs) will be placed in correspondence of each lens mount. For the dummy 4 little blocks will be fixed to the flanges through threaded holes. The same blocks will be moved from one flange to the others during the alignment procedure.

Breadboard AIV tools

1. Light shields between each couple of lenses (TOU) TBD after pre-breadboard

2. Tools for lenses insertion (TOU&Dummy) Each lens mount will have three threaded holes (120deg separated), insertion will be performed thanks to 3 long threaded bars

3. Tools for lenses centering during alignment (TOU&Dummy) 4 screws (2 of them with springs) will be placed in correspondence of each lens mount. For the dummy 4 little blocks will be fixed to the flanges through threaded holes. The same blocks will be moved from one flange to the others during the alignment procedure.

Breadboard AIV tools

1. Light shields between each couple of lenses (TOU) TBD after pre-breadboard

2. Tools for lenses insertion (TOU&Dummy) Each lens mount will have three threaded holes (120deg separated), insertion will be performed thanks to 3 long threaded bars

3. Tools for lenses centering during alignment (TOU&Dummy) 4 screws (2 of them with springs) will be placed in correspondence of each lens mount. For the dummy 4 little blocks will be fixed to the flanges through threaded holes. The same blocks will be moved from one flange to the others during the alignment procedure.

GLUE act as an interface between metal and glass.A discussion to finalize the lens gluing operation inside their mounts is going on with the industry (SELEX GALILEO, SESO, SAGEM), in order to identify a procedure which is: safe for the lens, thinking also to vibrations and thermal excursion compatible with the tolerances reasonably achievable on the lens geometry (diameter above all)

Gluing operations

compatible with the centering and tilt tolerances of the lenses feasible in a fast way also by the industry (considering the huge number of lenses)

GOAL: freeze the gluing protocol today

B-PLAN: - formal offer from SESO

- discussion with SAGEM

Breadboard Status

Lenses: Seso will deliver them in a month Thermally equivalent structure: delivery

roughly in a month from Bern Lens mounts: some little modifications are

necessary, mounts production will start in the next days

Handling: the delivery is expected in a month Tools: easy to implement. They will be ready

together with the rest of the mechanics Lab setup: it is the same used for the Pre-

Breadboard. Ready in OAPD lab.

Breadboard integration is expected to start at the beginning of April

TOU Bradboard test

Preliminary discussions with the industry have outlined this strategy for the TOU prototype test:

Warm test (Research institutes): being the alignment performed in warm conditions, a few test on the expected TOU “warm performance” are foreseen:

1) a test of the PSF optical quality on axis 2) an interferometric test of the TOU optical quality

Cold test (Research institutes + Industry): in a climate chamber operating in vacuum at the required temperature (-80º), we will perform:

3) a test of the PSF optical quality on axis 4) a Hartmann optical quality test

1) TOU PSF Test on axis in warm

Vis Illuminator

Optical FiberOff Axis Parabola

Collimated Beam

Tip-Tilting Flat Folding Mirror

Test Camera, adjustablein focus

Performed by the Research InstitutesPerformed by the Research Institutes

2) TOU Optical Quality Test in warm

Zygo GPI FPZygo GPI FP

F/1.5 Transmission Sphere 4" - 1/10 Wave, P-VDYNAFLECT Coated

Performed by the Research InstitutesPerformed by the Research Institutes

…”in cold” Test selection…

Problems due to the low testing T and to the gradient between inside and outside the Climate Chamber: The input optical window of the Climate Chamber is

affected by aberrations (“lens” effect) – Better to have collimated input beams

If the test requires auxiliary optical components inside the chamber, they will also be affected by aberrations and particular care shall be given to their mounts - Better not to use additional optics and minimize the number of mechanics inside the climate chamber

Robustness to sub-optimal projection systems - rely on centroiding spots other than on size/shape of these

3) TOU PSF Test on axis in cold Performed by the Research Institutes + IndustryPerformed by the Research Institutes + Industry

Vis Illuminator

Optical Fiber

Off Axis Parabola

Collimated Beam

Flat Folding Mirror

Test Camera remotelyadjustable in focus

Climate Chamber (T~-80º)

Input optical window

Advantages:Advantages:- Parallel beam in inputParallel beam in input- No other Optical Parts No other Optical Parts inside the chamberinside the chamber- Only 1 motorized axis in Only 1 motorized axis in coldcold

4) TOU Hartmann test in cold

If the relative position of P1 and P2 is known with anhigh accuracy (linear If the relative position of P1 and P2 is known with anhigh accuracy (linear stage with encoder), we can verify the optical quality in term of Encircled stage with encoder), we can verify the optical quality in term of Encircled Energy, even without going with the CCD there!Energy, even without going with the CCD there!

Advantages:Advantages:- Parallel beam in inputParallel beam in input- No other Optical Parts No other Optical Parts inside the chamberinside the chamber- Only 1 motorized axis in Only 1 motorized axis in coldcold

Performed by the Research Institutes + IndustryPerformed by the Research Institutes + Industry

Vis Illuminator

Optical Fiber

Collimated Beam

Off Axis Parabola

Hartmann Mask

Climate Chamber

Input optical window

CCD (movablein focus)

P1 P2

T~-80º

Procurement Status

The procurement of all the opto-mechanical components needed for the Pre-BB, for the BB, for the lab setup, for the “warm” and “cold” test has started and all the order have been placed since mid November 2010

The opto-mechanical components needed for the Pre-BB have been all delivered

The industrial studies concerning the feasibility of the aspherical lens and the AIV strategy for the 32 telescopes have been placed (Selex Galileo, Medialario, Fisba, RUAG Space)

The order of 2 CaF2 blanks have been placed 2 weeks ago (4 weeks delivery time from Korth Kristalle)

The industrial study on the AlBeMet Structure feasibility has been placed (APCO Technologies)

Time planning

Pre-Breadboard Alignment test results by end of this week

TOU Breadboard Opto-Mechanical and test components arriving by 31

Mar 2011 “Warm” alignment and test of the TOU prototype by

15 Apr 2011 “Cold” test in Galileo by 25 Apr 2011 Test report by 30 Apr 2011

This planning has no contingency present and it is based on the best effort delivery date of SESO

…toward Implementation Phase… Selex Galileo has been associated to the definition of the AIV

procedure and to the BB test in cold, in view of taking over the responsibility during the implementation phase

The date and conditions of the responsibility transfer to industry is under discussion at the moment, starting with the transfer of mechanical design (discussed with both Daniele Piazza and Selex Galileo)

The list of test to be performed on the TOUs during the Implementation Phase is under discussion

Galileo will propose a test strategy and planning for the definition phase, starting on the base of the first preliminary plan outlined at the beginning of the project: Each unit:

▪ thermal cycling ▪ vibration ▪ interferometric optical quality test ▪ focal plane position with respect to a TBD interface plane

One unit every 5 TOUs:▪ Optical quality test in terms of PSF variation over the FoV in flight conditions

The end

miCos positioner PLS-85