GWEF Oval Flat TRD 20220509.pdf

Technical Requirements

For

Oval Flat Mirror

For The

Guided Weapons Evaluation Facility

782 TS/RNWG

9 May 2022 ii

Revision History

Rev. No. Description Date

1 Initial Release 20220107

2 Revised low frequency form error threshold 20220323

3 Revised low frequency form error measurement area and coating reflectivity requirements.

20220509 iii

Abbreviations, Acronyms, and Symbols

Ravg Average Reflection g Force per unit mass due to gravity at the Earth's surface

GWEF Guided Weapon Evaluation Facility

” Inch (Inches) mm Millimeters nm Nanometers

RMS Root Mean Square

UV Ultraviolet λ Wavelength iv

Table of Contents

Abbreviations, Acronyms, and Symbols ....................................................................................... iii

Table of Contents ........................................................................................................................... iv

1. Introduction

2. Physical Requirements

3. Performance Requirements

1. Introduction

a. This technical requirements document is for a custom 16” oval flat mirror to be used at the Guided Weapon Evaluation Facility (GWEF), 782 Test Squadron/RNWG, Eglin AFB, FL. The oval flat mirror will be used to develop a GWEF test system and must be drop-in replacements to an existing GWEF test system. The terms “Threshold” and “Objective” may be used throughout this specification. A threshold is the minimum acceptable requirement. An objective is a desired capability.

b. Contractor proposals should identify any specifications that are not technically feasible or have an undue impact on cost. Should this occur, proposals should provide recommended alternatives to the identified specification as well as impacts on overall system performance and cost.

2. Physical Requirements

a. Mechanical Properties. In general and if not stated otherwise, mechanical properties shall be comparable to or better than the current Pyrex mirrors and custom aluminum mounts.

b. Mechanical Robustness. The mirrors and mounts must be able to operate in a dynamic motion environment and withstand up to 15 g lateral accelerations without damage.

c. Dimensional Stability. The components shall be dimensionally stable for 45-90 degrees Fahrenheit and 10-100% relative humidity.

d. Water Resistance. The components are required to have minimal water absorption with a goal of no absorption (non-hygroscopic). The components dimensional and mechanical characteristics shall not be affected by any absorbed water.

e. Chemical Resistance. Proposals shall indicate any chemical sensitivity of the mirror and mount materials. As a goal, the components should be chemically inert and not absorb or be affected by hydraulic fluids, common electronic and electrical component cleaning sprays, spray dusters, or chemicals normally used to clean optics, including water, alcohol, ammonia, and acetone.

f. Out-gassing. The components shall not out-gas products that would damage sensitive electronics, optics, or optical coatings.

g. The oval flat mirror physical volume shall be 16.2” x 11.7” x 1”.

h. The oval flat shall be assembled at the contractor facility using a GWEF supplied backing plate.

3. Performance Requirements

a. Oval Mirror Flat optical requirements are given in Table 1 below.

Table 1. Oval Mirror Flat Optical Requirements

Oval Mirror Flat Optical Requirements

Threshold Objective

Low Frequency Form Error (RMS reflected wave front error at 633 nm for spatial scale lengths over a 12” aperture) λ λ/20

Ripple/Periodic Error (RMS gradient for spatial scale lengths of 1-10 mm)

<10 micro-radians <5 micro-radians

Surface Roughness <20 angstroms <10 angstroms Scratch-Dig (RMS for spatial scale lengths of 2.5 – 80 microns (ISO 10110 default bandwidth)

60-40 10-5

Coating UV enhanced aluminum with protective overcoat Reflectivity, 300 – 700 nm (Ravg, 45 degree angle-of-incidence)

>84%

Reflectivity, 700-1000 nm (Ravg, 45 degree angle-of-incidence)

>80%

Reflectivity, 1000 – 5500 nm (Ravg, 45 degree angle-of-incidence)

>90%

HANK D. JACKSON II

Physicist

782 TS/RNWG