Statement of Work - Final 16 Jan 2025.docx

Statement of Work Primary Mirror Recoating for the Eugene Stansbery-Meter Class Autonomous Telescope (ES-MCAT) deployment to Ascension Island Auxiliary Airfield (AAF)

This SOW governs the process by which the contractor will provide (a) stripping a protected, enhanced silver coating on a 1.3m Zerodur® mirror, and (b) recoating the mirror with a protected aluminum coating optimized for the 360nm-1µm spectral bandpass.

The 1.3-m NASA ES-MCAT Telescope is located on Ascension Island.

1.0 TASK

ES-MCAT 1.3-m mirror recoating.

1.1 Background

The Orbital Debris Program Office (ODPO) at NASA Johnson Space Center (NASA- JSC) operates and maintains the 1.3-m ES-MCAT telescope at Ascension Island Auxiliary Airfield (AAF). The telescope was conceived, designed, and constructed by NASA- JSC and the Air Force Research Laboratory (AFRL) Detachment 15, Maui, HI. ES-MCAT’s purpose is to characterize the orbital debris environment in support of spaceflight safety. The primary observation goal for the telescope is extending geosynchronous orbit (GEO) coverage to smaller and fainter orbital debris than can be obtained from other available data sources.

The protected, enhanced silver coating currently on the 1.3-m Zerodur® mirror is degrading and must be removed and recoated with a new protected aluminum coating (or equivalent).

Specifications of the mirror are provided in the table below. Additional details may be provided as necessary.

Specifications of the Mirror

RMS WFE

(nominal) 42nm

The scope of work includes:

(1) Stripping the current enhanced silver coating, and possibly analyzing the degraded coating.

(2) Inspecting the underlying Zerodur® mirror for any etching.

(3) Recoating the mirror with a protected aluminum (or equivalent) coating, including witness samples and any necessary fixtures (if additional fixtures are required) to hold the mirror during the coating process. Note that existing mirror tooling is available from the original mirror coating.

1.2 Coating Objectives

Ascension Island is a highly corrosive sea-level, marine environment with 60-90% average humidity. The island is an extinct volcano with sulfur-rich volcanic dust. Thus, the reflective coating requires a protective overcoat appropriate for a highly corrosive environment.

The contractor shall (1) strip the current coating and (2) recoat the mirror with a commercial grade coating to meet the following minimum requirements. MIL- SPECS and ISO specs upon which the requirements are based are noted and intended to provide additional clarification for the vendor.

1.3 Coating Requirements

1. Reflectivity optimized for 380-750 nm spectral bandpass, e.g. protected aluminum or equivalent (such as dielectric only layers): MIL-PRF-13830B, section B.3.4 per requirements:

A. Minimum 85% average reflectivity across the above bandpass B. Minimum 85% average reflectivity across SDSS g′r′i′z′ bandpasses. (see Attachment 2 for a table describing the bandpasses for each filter) C. Minimum 85% must be met from the central hole of the mirror to within 5% of the outer edges of the mirror

2. Thickness of coating A. Reflective layer (e.g., aluminum undercoat) shall be 1000 Å +/- 10%, or as agreed upon by NASA and the vendor

3. Coating Edge A. Reflective coating should cover the glass to within 5 mm of the edge of the clear aperture.

4. Protective Topcoat A. Protective topcoat(s) shall overcoat the underlying reflective aluminum (or equivalent) layer via masking or other appropriate methods.

B. Protective topcoat(s) must withstand the highly corrosive environment on Ascension Island:

The front surface aluminum film (or equivalent) shall be protected by a uniform, high quality protective topcoat which should be free from holes, foreign matter, and perceptible variations in density. (MIL-PRF-13830B, section B.3.3.2 Protective film).

· Adhesion test shall be done on the ES-MCAT mirror.

· All other tests are anticipated for witness samples that are coated concurrently with the ES-MCAT mirror, and subject to agreement between NASA and the vendor.

Topcoat shall pass the following tests:

C. Adhesion: ISO-9211-4: Test 6.2.1

i. tape test: #800 Magic tape, 90 degree,

1. See ISO-211-4: 6.2.1 Test Conditions for further details

2. See ISO-211-4: 6.3, Table 2 for slow pull specs: ~2-3s per 25mm D. Abrasion: ISO-9211-4, moderate abrasion test 5.2.2

i. The coated optical surface shall show no signs of deterioration such as streaks or scratches when abraded with 50 strokes of cheesecloth applying 5N ± 1N of force.

E. Physical: ISO-211-4, section 8.5 Evaluation

i. Shall show no signs of flaking, peeling, cracking, or blistering.

F. Cosmetic: ISO-211-4, section 8.5 Evaluation

i. Shall be free of stains, smears, discolorations, streaks, hazy/cloudiness G. Environmental and Physical Durability Subsequent to these tests/exposures, the coated optical surface shall meet the 4.A.i Physical and 4.A.ii Cosmetic requirements above for all durability tests.

See ISO-9211-4: 8.4 Recovery: After tests, mirror shall be gently cleaned with soft clean optical cloth not warmer than 38C.

i. Cleaning Durability MIL-C-48497A

1. After immersion in acetone and ethyl alcohol and wiping with optical-grade cotton or an appropriate clean, soft optical-grade cloth, the coated optical surface shall show no evidence of coating removal or scratches.

2. And/or cleaning with a mild detergent (proposed by vendor) + water shall leave no evidence of coating removal or scratches.

ii. Humidity Test

1. 90-95% relative humidity @50C for 24 hours

iii. Optical Durability - Solubility Tests

1. Water Solubility (ISO-9211-4)

a. Immersion in distilled water, see ISO-9211-4: 8.2 Test Conditions for further details

b. 24-hour exposure time, 1 cycle, 23± 2C ISO-9211-4: 8.3 Table 4 degree of severity #02

2. Salt Solubility (ISO-9211-4)

a. Immersion in a saline solution, pH = 6.5-7.2 See ISO- 9211-4: 8.2 Test Conditions for further details

b. NaCl dissolved in distilled or deionized water at room temperature to obtain a concentration of 45 g/l. NaCl shall not contain >1% impurities in total

c. 24h exposure time, 1 cycle, 23± 2C ISO-9211-4: 8.3 Table 4, degree of severity #05

iv. 24-Hour Salt-fog Corrosion Test (MIL-STD-810G_CHG-1.pdf, Method 509.6) See ISO-9211-4: 8.4; for corrosion (vs. test E.iii.2 for solubility)

1. Recommended 35± 2C

2. 4 cycles x (12-hour exposure, 12-hour dry) preferred

a. Alternatively, 2 cycles x (24-hour exposure, 24-hour dry) may be completed as agreed upon by NASA and the vendor

3. A 5 ± 1% by weight NaCl salt solution concentrate (section 2.2.1 and p. 260: 4.5.1.1.b)

a. <0.1% Sodium Iodide

b. <0.5% total impurities

c. no anti-caking agents

v. Acid Corrosion Test (ISO 9022-12-1 Chemical Durability Environmental test; or MilStd810G, Method 518.2)

1. 23 ± 2C

2. 6-hour exposure, 18-hour storage prior to cleaning

3. Sulfuric Acid: 2.5% H2SO4/sulfuric acid

a. OR 11.9mg (6 µl) sulfuric acid (95-90%) per 4 L of distilled or deionized water (MilStd810G, Method 518.2, p.659)

b. OR hydrogen sulfide (pH 6.9);

vi. Alkaline Corrosion Test (ISO 9022-12-2, ISO 10629: Chemical Durability Environmental test: 24-hour, 50C)

1. 23 ± 2C

2. 6-hour exposure, 18-hour storage prior to cleaning

3. Sodium hydroxide, c=0.01 mol/L, pH=12; (ISO 10629, 1996)

a. Or Potassium hydroxide (pH 11.95)

5. Coating removal The current coating to be removed is a protected, enhanced silver coating manufactured by ZeCoat Corporation.

A. Non-dielectric coats (reflective and protective overcoat, e.g. protected aluminum) shall be chemically strippable without damaging the underlying Zerodur® mirror.

B. Dielectric coating removal options (e.g. chemically dissolving versus removal via polishing) will be proposed by the vendor and must be accepted by NASA prior to coating the mirror.

6. Tests and Inspection for Optical Quality (MIL-PRF-13830B) Including 4.2.2 Surface Quality Inspection Methods No.1 and 2 for both the reflective and topcoat(s) layers (Backlit and forward lit inspections) A. Method 1: The element to be inspected shall be viewed against a ground glass or opal surface illuminated from behind by a 40 watt incandescent or 15 watt cool white fluorescent lamp approximately 3 inches from the glass. Two or more opaque horizontal bars occupying approximately 1/2 the area of the glass shall be placed in front of and in contact with the glass.

B. Method 2: The light through ground glass from a 40 watt incandescent or 15 watt cool white fluorescent lamp shall be passed through the element. Defects are observed by light scattered from the surface while viewing it at approximately 90 degrees to the path of the beam against a dark background.

7. Tests and Inspection of Existing Coating A. Test stripping techniques of the existing coating prior to the mirror’s arrival. NASA will provide witness samples of the existing coating for this purpose.

B. Provide an analysis of degraded coating of the mirror to identify mitigation steps or improvements in the new coating that can be implemented to increase its expected service life, if deemed necessary by NASA and the vendor.

8. Required Fixtures/Tooling used to Fasten Mirror Note: Tooling fabricated for the original coating will be provided to aid in removal of the existing coating while any required new tooling is fabricated, if necessary.

Existing tooling from the original coating is comprised of a split band that grips the outside edge of the mirror with spacers between the mirror edge and band. Four spacers overlap the mirror on the front and back to prevent the mirror from slipping through the band. Further, the band has 2 sub axles (180deg apart) with 2 straps connecting to those axles to allow the mirror to be lifted and hung in the vacuum chamber. This tooling allows for the mirror to be rotated from edge-up to surface up or down. Further information and drawings can be obtained from NASA as necessary.

A. If required, design new tooling/fixtures appropriate for handling the mirror for the new coating B. If new tooling/fixtures are required, fabricate a mass model to test the fixture C. If required, fabricate the newly designed tooling/fixtures. Please include pricing/schedule for fabrication of new tooling/fixtures.

D. If existing tooling can be used with modification, design and fabricate appropriate adapter. Please include pricing/schedule for fabrication of tooling adapters.

E. It is preferred to keep the lugs on the side of the mirror in place. If they need to be removed for coating, this will be agreed upon by NASA and the vendor in advance.

9. Witness Samples A. Witness samples from a qualification coating (i.e., the coating intended to be the final coating design for the ES-MCAT mirror) shall be coated in the large chamber that will also be used to coat the ES-MCAT mirror, using coating techniques as similar as possible to those that will be used for the final ES-MCAT coating.

i. A surrogate should be used to replicate the actual dimensions of the ES-MCAT mirror to ensure test run results match final coating, as agreed upon by NASA and the vendor.

ii. Additional witness samples coated during any research and development (R&D) phases may be coated in smaller chambers for efficiency.

B. Number of witness samples coated during production coating concurrently with the ES-MCAT mirror that are needed to efficiently test the conditions above will be agreed upon with the vendor prior to the mirror coating.

C. At least 4 additional witness samples (2 coated inside the mirror annulus, 2 exterior) will remain pristine (untested).

D. Witness samples from the full mirror coating shall be delivered at the same time as the coated mirror.

10. Tests and Inspection for Coating Pinholes A. Witness samples from the coating qualification run shall be imaged using scanning electron microscopy (SEM). SEM imagery may be done at the coating vendor’s facility or witness samples may be shipped to NASA for imaging. SEM images will be taken at several points on each witness sample and at a scale agreed upon by NASA and the vendor.

i. If SEM imagery is completed by the vendor, the vendor shall provide specifics of the imaging process (including the scale used for the images) and deliver the images to NASA for analysis.

ii. At least 2 witness samples (1 interior and 1 exterior) shall be provided for SEM imagery analysis.

B. SEM images will be subsequently assessed by the NASA team for the number and size of pinholes in the coating.

C. SEM analysis shall be a “go/no-go” milestone for production coating of the full mirror.

11. NASA Inspections A. NASA representatives shall be allowed to:

i. Visit the vendor site to review the mirror coating process, for example to:

1. Review/inspect the corroded mirror coating with the vendor and determine if any modifications to the mirror coating or future mitigation options are needed

2. Review/inspect the witness samples coated during the qualification run with the vendor and determine if any modifications to the final coating design are needed

3. Review testing of the final mirror coating

ii. Visit the vendor site to inspect the final coated mirror prior to packaging for shipment

12. NASA Approval of Coating Design A. Approval by NASA of the final coating design will include:

i. Ensuring coatings meet the agreed upon reflectivity requirements, balanced with protection by the overcoat

ii. Ensuring coatings meet an acceptable level of pinhole number and size, as determined by NASA acceptance criteria

iii. Coatings shall be strippable without damaging the mirror

1.4 Coating Deliverables

1. If deemed necessary, analysis of the mirror’s degraded coating,

a. This may include analysis of the corroded coating on the primary mirror at time of delivery to the coating vendor.

2. Analysis of the surface (etching) of the bare Zerodur® mirror

a. After removal of old protected silver coating, assess whether any etching of the bare Zerodur® mirror surface has occurred. This will be done to determine whether polishing (and/or grinding) is necessary as preparation for the new coating (see Section 1.3 for tolerance).

3. Quality Management Plan for the chamber and the process by which the coating will be produced by the chamber.

a. Higher quality coating standards, for example as are typically used for laser optic applications, should be implemented as agreed to by NASA and the coating vendor.

4. Quality Control Certification Report of the final coating on the mirror showing that the coating meets all requirements in Section 1.3, including, but not limited to:

a. Physical

i. Blemishes

ii. Verification of coating thickness

iii. Edge coating requirement

b. Reflectivity

i. Spatially: verify across the full bandpass from the inner to outer annulus of the mirror

ii. Spectrally: plots of reflectivity as a function of wavelength

c. Results of tests performed

5. Tooling/Fixtures

a. If needed to replace existing fixtures that will be provided by NASA, fixtures that will be used to hold the primary mirror during the recoating process

b. If agreed upon, trunnion or cart custom made for this project

6. Witness Samples

a. Zerodur® glass witness samples coated during the qualification run, at least 2 (1 interior and 1 exterior) of which will be provided for SEM imagery analysis

b. SEM images of the witness samples coated during the qualification run, if imagery is completed by the vendor

c. Zerodur® glass witness samples coated simultaneously with the primary mirror (interior and exterior to the mirror at regular spacing) that allow efficient testing of the coating, the minimum number of which shall be agreed upon by NASA and the vendor, plus a minimum of 4 (2 inner, 2 outer) pristine witness samples

7. Coated Mirror

a. Coated mirror with protected aluminum coating or equivalent to meet objectives above in Section 1.3.

2.0 Place of Performance

NASA will coordinate and fund the transportation of the mirror to and from the vendor’s facility where all coating services will be performed.

3.0 Delivery

Delivery shall be as specified within the contract.

4.0 Schedule and Milestones

The planned major milestones for this task are as follows:

*It is anticipated that milestones 1, 3, and 5 can be completed in parallel.

†NASA intends to ship the existing tooling before the mirror is shipped to facilitate the tooling build. NASA will ship the existing tooling NET the effective date of the agreement and NLT with the mirror shipment. Mirror and existing tooling shipment dates are dependent on military transport schedules between Ascension Island and Patrick Space Force Base, Florida.

‡Milestones 7-9 will not be completed in the event of a “no-go” decision

5.0 Payment Expectations and Right to Contract Cancellation

Surrogate witness samples shall be coated during the qualification run (as defined in Section 1.3.9.A) and subsequently assessed via SEM pinhole analysis (as described in Section 1.3.10). This analysis will determine NASA acceptance of coating development and qualification and will be the “go/no-go” milestone for the full production mirror coating. If the witness samples do not meet coating requirements as described in Section 1.3 (including, but not limited to, environmental tests and SEM imagery analysis for pinholes), and a suitable plan for remediation does not meet the expected technical requirements and/or required schedule, NASA reserves the right to cancel the contract without penalty. If NASA exercises this right to cancel the contract with a “no-go” decision, NASA shall only remit payment to the vendor totaling the cost for the qualification coating development, witness sample coating, SEM imagery (if completed by the vendor), tooling development (if completed at the time of this milestone decision), and mirror stripping (if completed at the time of this milestone decision); no further payment will be permitted or approved unless approved by the Contracting Officer through the applicable Disputes and/or Request for Equitable Adjustment clauses, as allowed through FAR 52.233-1 Disputes.

6.0 Coating Warranty

Coating manufacturer shall provide details of any warranties for the coating, including timeline and costs. At a minimum, a coating warranty should cover stripping and recoating the mirror in the event of an agreed-upon defect.

7.0 Acceptance of Deliverables

All deliverables will be considered accepted upon official notice from the NASA Contracting Officer.

8.0 Expertise Requirements and Considerations

Coating manufacturer shall provide evidence of experience and past performance in meeting MIL-specs requirements defined in Section 1.3 for professional grade observatories.

Coating manufacturer shall provide experience and past performance in developing/applying protective overcoats appropriate for highly corrosive environments.

Coating manufacturer shall provide experience and past performance in working with mirrors of at least 1.3m diameter and 800lb weight.

9.0 Contracting Officer’s Representative (COR)

The COR is designated by the Contracting Officer to perform technical liaison between the contractor’s management and the Contracting Officer in routine technical matters constituting general program direction within the scope of the contract. Under NO circumstances is the COR authorized to effect any changes in the work required under this contract whatsoever, or enter into any agreement that has the effect of changing the terms and conditions of this contract, or that causes the Contractor to incur any costs.

In addition, the COR will NOT supervise, direct, or control contractor employees. Notwithstanding this provision, to the extent that contractor accepts any direction that constitutes a change to his contract without prior written authorization of the Contracting Officer, costs incurred in connection therewith are incurred at the sole risk of the contract, and if involved under this contract will be disallowed.

On all matters that pertain to the contract terms, the contractor must communicate with the Contracting Officer. Whenever, in the opinion of the contractor, the COR requests efforts beyond the terms of the contract, the contractor shall so advise the Contracting Officer. If the COR persists and there still exists a disagreement as to the proper contractual coverage, the Contracting Officer will be notified immediately, preferably in writing.

Proceeding with work without proper contractual coverage may result in nonpayment or necessitate submittal of a contract claim. The prime contractor’s management should clearly communicate this position to its employees working on this contract and to any subcontractors also providing support.