Objective, Dome Material/Fabrication: Mid-wave material Extreme environmental durability

1. Objective, Dome Material/Fabrication: • Mid-wave material • Extreme environmental durability • Technology available to ‘form’ into a monolithic hyper-hemispherical configuration • Accurate and repeatable High-speed optical fabrication process • Cost effective combination of materials and processing

2. Material Option(s) review: • Spinel. • Silicon • ALON

3. Foreign Object Damage, testing: • Testing on ALON, Silicon and Fused Silica. • Being performed at UDRI • Simulate aircraft foreign object damage from take-off/landing (20 m/s to 75 m/s) • Testing being conducted by launching 3/8” diameter granite projectiles into the window samples using a .50 caliber bore compressed-gas gun. • Parts rigidly mounted at 450 AOI • A laser photodetector system has been employed to measure the projectile impact velocity • All parts are being photographed before and after test

4. Foreign Object Damage, testing:

5. Strength of Material, Improvement, ALON • The objective of the ALON strength enhancement program were to increase the strength of ALON so that high thermal shock resistant domes could be made. • Several years of fabrication/thermal processing development yielded a significant increase to the ultimate strength of ALON

6. Strength of Material, Improvement, ALON Successful Thermal Shock-testing of Domes + much higher ultimate strength exhibited by equi-biaxial flexure testing of plano samples validates the modified material process’

7. ‘Forming’, ALON

8. ‘Green’ Machining, ALON

9. ‘High-Speed’ Optical Fabrication, ALON

13. Thin-film Coatings

14. Thin-Film