In an account published by Phys.org on October 14, 2026, NASA reported that small SPEARS prototype cells operated at −80 °C (−112 °F) in thermal-vacuum testing, with somewhat reduced performance. NASA says the cells survived exposure to temperatures as low as −170 °C (−274 °F), but would not operate at that temperature. NASA’s account of the SPEARS tests
What the tests reported
| Test or stage | Temperature or condition | Reported result |
| Operation | 80 °C (176 °F) and −60 °C (−76 °F); also −80 °C (−112 °F) | Good operation at 80 °C and down to −60 °C; somewhat reduced performance at −80 °C |
| Exposure | 100 °C (212 °F) to −170 °C (−274 °F) | No damage reported after exposure; the cells would not operate at −170 °C |
| Recovery after extreme cold | Small heaters | Intended to warm the cells back to operating temperature |
Operating at −80 °C and surviving exposure to −170 °C are different results. NASA’s account describes the first as operation with reduced performance and the second as survival after exposure. The account also cites lunar south-pole nighttime temperatures as low as −200 °C (−328 °F), colder than SPEARS’s reported operating point.
A solid electrolyte and a planned warm-up
SPEARS—Solid Power for Extreme Environment Adaptability and Resilience in Space—is developing cells that use solid ceramic- or polymer-based electrolytes instead of liquid electrolytes. Small heaters are intended to bring the cells back to operating temperature after extreme cold.
NASA says the project began in 2026. NASA Glenn Research Center leads it, and NASA Langley Research Center is the site of the reported thermal-vacuum tests. NASA Ames Research Center is developing test boards and electronics to prepare SPEARS battery hardware for spaceflight testing.
Potential uses on the Moon
NASA identifies astronaut emergency power packs, drills, rovers operating in shadowed craters, and long-duration scientific instruments as possible applications. SPEARS is a technology-development project for potential future lunar operations.
SPEARS is distinct from other lunar-energy concepts
SPEARS uses solid-electrolyte battery cells. Xataka describes a separate regenerative fuel-cell concept that cycles hydrogen and oxygen through water to store and generate energy. Xataka’s description of the regenerative fuel-cell concept
Híbridos y Eléctricos describes another separate research effort: 3D-printed sodium-ion battery components made using lunar and Martian materials. Híbridos y Eléctricos’ report on regolith-based battery research
