The last time NASA collected data on the heat emerging from the moon's interior was when the space agency still sent astronauts on Apollo missions.
The lunar heat-flow study had seemingly ended. Because the data can't be obtained with orbiters, no further measurements were taken after just two were made in the 1970s. But all that has changed since Texas-based company Firefly Aerospace successfully landed Blue Ghost on the moon on March 2.
The uncrewed spacecraft, carrying 10 NASA experiments, has just achieved the first collection of heat-flow data without humans, solely using robotic technology. Called the Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity, or LISTER, the instrument has been drilling into the lunar soil. Mission controllers have watched it digging underground through a video transmission beamed back to Earth.
"By making similar measurements at multiple locations on the lunar surface, we can reconstruct the thermal evolution of the Moon," said Seiichi Nagihara, a geophysics professor at Texas Tech University and LISTER's principal investigator, in a statement.
The findings from the experiment will help to reveal the geological processes that shaped the moon over its 4.5 billion-year history, from its start as a mere ball of molten rock. Over time, it cooled by releasing its inner heat into space.
Firefly Aerospace's mission control watches NASA’s Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity, or LISTER, drill into the lunar surface on March 3, 2025 in the above video.
Firefly is the first company to get its lander to the moon upright and in one piece. The difficulty of that feat was underscored last week when Intuitive Machines, the first company to land on the moon last year (albeit tilted), was not able to even duplicate its partial success on its return. Intuitive Machines' Athena lander seemingly toppled in a crater, with its solar panels not pointing toward the sun. With the spacecraft unable to generate and replenish power, the company already announced the mission was over.
Firefly's Blue Ghost lander, named after an exotic type of firefly, is now sitting in Mare Crisium, a lunar plain made from an ancient hardened lava flow. It's next to a volcanic feature, Mons Latreille, in the northeast quadrant on the near side.
NASA paid Firefly $101.5 million to build the spacecraft and deliver LISTER and nine other payloads to the moon through its Commercial Lunar Payload Services program. The space agency wants to see a regular cadence of moon missions to prepare for astronaut-led Artemis expeditions in 2027 or later.
LISTER, mounted below Blue Ghost’s lower deck, measures the flow of heat from the moon's interior with a sophisticated pneumatic drill, developed by Texas Tech and Honeybee Robotics. The tool, essentially a jackhammer that uses compressed gas to power the drilling action, has a needle sensor on the end to take temperature readings.
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About every 1.5 feet, the drill stops to extend the thermal probe into the surrounding rocks, dust, and pebbles. The instrument then measures two things: thermal gradient, or the temperature changes at various depths, and thermal conductivity, which is the soil's ability to let heat pass through it. The drill can plunge to an ultimate depth of nearly 10 feet underground.
"Instruments such as LISTER help us to learn more about the surface of the moon and how we can be there for a longer period of time and take advantage of resources available to us," said Mike Selby, LISTER manager at NASA's Marshall Space Flight Center, in a video about the payload.
Firefly's mission is a little more than halfway complete, expected to come to an end shortly after lunar nightfall.
