SRI helps build ultraviolet detectors for NASA’s UVEX mission

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New CMOS sensors will help map the entire sky in ultraviolet light for the first time.

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A new NASA space telescope will be up to 100 times more sensitive to ultraviolet light than its predecessor, and SRI is helping build detectors that make it possible.

Stars don’t sit still. They flare, explode and collide, scattering heavy elements across the universe. Much of that activity shines brightest in ultraviolet light, which is invisible to the human eye. And it has never been mapped in depth across the whole sky. As part of the Caltech-led mission, SRI and NASA’s Jet Propulsion Laboratory (JPL) will produce the mission’s ultraviolet detectors.

CMOS (complementary metal–oxide–semiconductor) integrated circuitry was first introduced at SRI (then the David Sarnoff Research Center) in the 1960s. In the 1990s, JPL invented CMOS active pixel sensors, which now sit inside billions of smartphone cameras. The UVEX CMOS detectors are modified using techniques refined over decades at JPL and SRI, with specialized filters and coatings that can detect ultraviolet wavelengths. They are a key reason UVEX is expected to be up to 100 times more sensitive than its predecessor, NASA’s Galaxy Evolution Explorer.

That sensitivity will let UVEX find millions of small, star-forming galaxies, follow neutron star collisions and supernovae within hours of an alert, and capture spectra that reveal what those explosions are made of.

UVEX is led by Caltech’s Fiona Harrison and managed by UC Berkeley’s Space Sciences Laboratory, with Northrop Grumman building the spacecraft. It will be the first major ultraviolet space mission in two decades.

SRI’s contribution draws on decades of work in CMOS imagers for demanding, low-light environments like deep space. In 2025, NASA’s Parker Solar Probe, equipped with CMOS imagers from SRI, released the closest images of the sun ever recorded.  

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