What lightweight, radiation-absorbing material did a study on engineered E. coli on the ISS in January 2026 find was greatly reduced in microgravity?

A recent study conducted aboard the International Space Station (ISS) in January 2026 investigated the capabilities of engineered E. coli to produce a vital biopolymer, revealing a significant challenge for future long-duration space missions. The research, part of the Melanized Microbes for Multiple Uses in Space Project (MELSP) by the U.S. Naval Research Laboratory, found that the production of melanin, a lightweight and radiation-absorbing material, was greatly reduced in microgravity compared to identical samples on Earth. This unexpected outcome highlights how the space environment can alter microbial metabolism and limit the efficiency of biological manufacturing processes.

Melanin is a natural pigment renowned for its multifunctional properties, including radiation-shielding, antioxidant, and thermal stability characteristics. Its ability to protect against harmful environmental factors, particularly radiation, has made it a subject of intense interest for space applications, such as developing protective coatings for spacecraft and spacesuits, or even for direct astronaut protection. The interest in melanin for space protection grew partly from observations of fungi at the Chernobyl (Review) nuclear power plant, which produce large amounts of melanin as a protective mechanism against radiation.

The findings from the ISS study, published in npj Microgravity, indicate that while engineered E. coli can still produce melanin in space, microgravity significantly interferes with crucial cellular processes like substrate transport, cellular stress responses, and metabolic balance, ultimately hindering production efficiency. This means that for microbes to reliably manufacture materials like melanin for deep space exploration, scientists will need to redesign both the microbes themselves and the systems in which they grow to account for the unique conditions of a weightless environment. Understanding these microgravity-induced constraints is essential for optimizing biomanufacturing in extraterrestrial settings.