Modernizing space food for long-duration missions

“We can do a direct replacement of thermal stabilization with electron beam,” Pillai said.

More than just nourishment

Today, much of NASA’s shelf-stable food is thermally processed, or heated and packaged in pouches to ensure sterility. While effective for food safety, the process can alter texture, appearance and flavor. Electron beam processing, by contrast, uses ionizing energy rather than heat to eliminate harmful microorganisms, which can help preserve food quality while still meeting strict safety requirements.

Because the process is continuous rather than batch-based, eBeam technology can prepare more food for space travel, a potential advantage as private companies and international space programs scale up human spaceflight for future trips to the moon and possibly Mars.

“You need a lot of food made,” he said. “And food is psychological. People want to eat food not only for nourishment, but for psychological reasons.”

Preserving texture and visual appeal of food becomes especially important on long-duration missions, such as voyages to Mars or extended lunar stays, Pillai said.

Raising outdated standards

Current radiation dose standards for space food were established in the 1960s, when sterilization science was still developing, Pillai said.

“They reflect a time when understanding of radiation dose and sterility was in its infancy,” he said.

NASA historically required a minimum dose of 44 kilograys for irradiated foods. Pillai said modern sterilization science, however, demonstrates that equivalent microbiological assurance can be achieved at significantly lower doses, typically between 15 to 20 kilograys.

Lower doses could improve  food quality while meeting safety requirements.

National security considerations

NASA has traditionally relied in part on cobalt-60 sources for food irradiation. Pillai said newer electron beam and X-ray technologies offer advantages.

“There is no need to continue using cobalt-60,” he said. “Electron beam reduces the risk.”

Cobalt-60 materials carry security and regulatory implications. Electron beam systems, by contrast, are electrically generated and can be turned on and off, reducing long-term material risks.

Opening the door for commercial space food

Pillai said advances in sterilization science have led other industries, such as medical device manufacturing, to use dose-based sterility assurance models rather than fixed minimum dose requirements.

Beyond ready-to-eat meals, Pillai’s graduate students have also studied combining freeze-drying with electron beam processing to improve the safety of delicate produce such as strawberries and blueberries.

The approach could reduce microbial risks while preserving structure and flavor, an appealing option for future crews spending months or years in space, he said.

“The technology has come a long way since the 1960s,” Pillai said. “As missions evolve, space food systems should evolve with them.”