CMOS image sensor inventor reflects on technology’s journey from space to smartphones

The CMOS image sensor, often called a “camera-on-a-chip,” grew from NASA’s need for small, low-powered cameras on interplanetary spacecraft. Dr. Eric R. Fossum invented the technology, which now supports cameras in phones, doorbells, Advanced Driver Assistance Systems, and spacecraft.

Before CMOS, photography relied largely on film or Charge-Coupled Devices (CCDs). Apollo 11 used purpose-built Hasselblad cameras that were too heavy to return to Earth, so astronauts brought back only the film. The cameras remained there.

CCDs improved image quality and reduced weight but used substantial power and generated heat. CMOS gave each pixel its own conversion circuit and amplifier, allowing simultaneous readout while reducing energy use and heat.

Fossum said he expected the technology to become widespread but did not foresee its social-media applications, effects on citizen-newsgathering, or implications for social justice. He also acknowledged concerns about privacy and liberty.

NASA and JPL helped advance digital imaging. Eugene F. Lally at JPL proposed a “mosaic” pixel array in 1961. Fossum later worked on CMOS QIS research at Dartmouth and Gigajot, enabling single-photon detection at room temperature and low voltages. SPAD technology has advanced over the past 20+ years, offering more precise pixel-arrival time-tagging but requiring larger pixels and more power. Stacked wafer devices and 3D integration remain promising directions.