NASA is developing solid-state batteries designed to operate safely in the Moon’s harsh environment as part of the Solid Power for Extreme Environment Adaptability and Resilience in Space (SPEARS) project. The project aims to provide a power source for future Artemis missions, ranging from emergency kits and exploration robots to scientific instruments and rovers.
Nighttime temperatures near the Moon’s south pole can reach about 328 degrees Fahrenheit below zero, equivalent to 200 degrees Celsius below zero. This range presents a challenge for conventional batteries, which rely on a liquid electrolyte that may freeze in extreme cold or evaporate in the vacuum of space. They are also affected by the high temperatures during the lunar day.
Thermal Test Results
Small prototype cells were used in thermal and vacuum tests conducted by a NASA team at the Langley Research Center in Virginia. The cells operated well at temperatures as high as 176 degrees Fahrenheit, or 80 degrees Celsius, and continued to operate down to 76 degrees Fahrenheit below zero, with a slight decline in performance at 112 degrees Fahrenheit below zero, or 80 degrees Celsius below zero.
Yi Lin, the test and research lead for the SPEARS project at Langley, said the team demonstrated for the first time that these cells could operate at 80 degrees Celsius below zero. The tests also showed that the batteries suffered no damage after being exposed to fluctuations ranging from 212 degrees Fahrenheit to 274 degrees Fahrenheit below zero, equivalent to between 100 degrees Celsius and 170 degrees Celsius below zero.
What Changes in Practice?
The SPEARS project replaces the liquid electrolyte with a solid material made of ceramic or polymer. This does not mean that the battery will operate at the lowest temperatures to which the lunar surface may be exposed; the cells require limited heating before resuming operation. However, the solid electrolyte does not freeze in the same way as a liquid, allowing the battery to withstand exposure to extreme cold without damage.
This approach could reduce the need to keep batteries warm continuously, potentially lowering the mass of thermal-management systems in lunar vehicles and facilities while enabling lighter designs and longer operations. These benefits remain dependent on the technology’s ability to progress from small test cells to flight-qualified hardware.
From Lunar Tools to Terrestrial Applications
NASA is studying the use of the batteries in drills operating inside shadowed craters, rovers, emergency power packs, and long-duration scientific instruments. According to NASA, the battery chemistry can be modified to achieve different priorities, such as energy density, power, or durability.
The SPEARS project began in 2026 with funding from the Advanced Research and Technology Division of NASA’s Mission Research and Technology Directorate. In its initial stages, it focuses on developing the technology, with the possibility of moving later to commercial collaboration. Ames Research Center is working on developing flight hardware, including test boards and electronics, in preparation for testing the batteries in space environments.
Although the project’s primary motivation is space exploration, NASA points to broader potential uses for solid-state batteries in cars, phones, communications equipment, and drones. The current status demonstrates that the prototype cells can withstand harsh thermal conditions, but it does not yet demonstrate their full operational readiness or use in a lunar mission.