Inprentus ships curved gratings for NASA solar mission

Inprentus delivered the first set of highly concave diffraction gratings for NASA’s ESIS-II solar science mission in early August, marking a technical milestone for the Champaign, Illinois company. The shipment is the first of two grating sets under a NASA SBIR Phase III contract and supports testing of an instrument designed to improve solar storm and space weather forecasting.

Why it matters: - The delivery advances NASA’s ESIS-II mission, which is designed to capture extreme ultraviolet solar data and help improve space weather forecasting. - The gratings are a technical fit for curved optical systems that must form sharp images from a highly specialized solar instrument. - The flight set that follows will support observations relevant to both satellites and crewed missions.

What happened: - Inprentus delivered the first set of spherical, highly concave diffraction gratings for a NASA-sponsored solar science mission in early August. - The shipment is the first of two sets Inprentus will produce for the ESIS-II, or EUV Snapshot Imaging Spectrograph II, mission. - The work is being done under a NASA Small Business Innovation Research Phase III contract. - The delivery was the first major shipment of seven out of fourteen contracted gratings.

The details: - The gratings were ruled on seven highly concave spherical substrates with a specialized triangular shape. - The ESIS-II gratings are formed on spherical surfaces curved to match the inside of a six-foot-diameter ball. - Inprentus used contact lithography to follow the curved contours of the substrates and form grooves with variable line spacing. - Each grating contains thousands of grooves placed within a custom-shaped, optically polished area of the substrate. - Inprentus’ dynamic contact mode lithography technique shapes the grooves to diffract extreme ultraviolet light with maximum efficiency. - The same process “blazes” the groove shape so the grating supports precise scientific measurements. - Inprentus said its programmable digital ruling architecture uses 8 axes of control and now includes a 9th axis to better follow curved contours. - Chief Technology Officer Cody Jensen said the technical team wrote custom path scripts to meet the curvature requirements. - Senior Development Engineer Nick Toombs said the added axis makes the platform more robust for freeform gratings. - The first grating set will be used for ground testing of the ESIS-II optical system. - The flight-ready set is scheduled for delivery later this year.

Between the lines: - The shipment shows that Inprentus can manufacture optics for unusually complex, highly curved surfaces, not just conventional flat grating formats. - The project also suggests NASA is pushing instrument designs that can gather more detailed solar data in a smaller observational window. - The move from ground-test hardware to flight hardware later this year will be the key proof point for the program.

What’s next: - Inprentus will produce and deliver the flight-ready grating set for ESIS-II later this year. - NASA’s instrument team will use the gratings to support simultaneous video capture at multiple extreme ultraviolet wavelengths. - The mission data is expected to help scientists track how hot solar gases move during solar storms. - The resulting measurements are intended to improve forecasting for space weather impacts on satellites and human spaceflight.

The bottom line: - Inprentus has cleared a difficult manufacturing hurdle for a NASA solar mission, and the next delivery will determine how the optics perform in flight-ready form.