Aero-optics Kit for Wind Tunnel Testing and Hypersonic Flight Evaluation

To meet the challenge imposed on the seeker window by the hypersonic flight envelope, new materials and processes are being developed to impart the required mechanical and optical performance characteristics including, but not limited to, strength, fracture toughness, thermal shock resistance, optical transmission, scattering, shape uniformity, etc. These “new” materials can be opaque in the visible, yet still have a high transmission and low emissivity in the Mid-Wave InfraRed (MWIR). While these new materials may present some performance advantages over “traditional” materials (e.g., Sapphire, Spinel, Alon, etc.), they introduce a new problem; namely, metrology. Traditional materials offer the opportunity to utilize visible-wavelength metrology equipment and approaches to indirectly measure the MWIR performance by scaling the visible metrology results to the MWIR wavelength(s) of interest. This technique of utilizing visible wavelength metrology to indirectly measure MWIR performance is colloquially referred to as “wavelength scaling” and has been widely practiced by many, if not all, performers in the field of aero-optics. Wavelength scaling is especially useful for measuring the wavefront transmitted through the various flow layers associated with hypersonic flight. Polaris’ Aero-Optics Kit (AOK) provides an aero-optics measurement capability that can be common among Ground Test Facilities (GTFs), regardless of their physical layout. “AOK Module 4” for the new(er) materials and windows is currently under development. Module 4 will include a MWIR PSF camera and a IR WFS to accommodate materials that have desirable properties only in the IR spectrum. Once developed, this pathfinder capability will pave the way for the prime contractors to efficiently utilize the GTFs in a manner that reduces MDA’s acquisition risk. Approved for Public Release | 22-MDA-11339 (13 Dec 22)