On the moon, not much can survive the arctic plunge of nightfall, where temperatures can dip to -330 degrees Fahrenheit for the two-week stretch of darkness each month. 

As more nations and private space companies attempt uncrewed moon landings, the dangers of lunar exploration have come into sharp focus. Even robotic missions that survive touchdown face another major threat: the brutal cold of the lunar night. Few landers and rovers ever wake after enduring the deep freeze. At cryogenic temperatures, soldered metal joints begin to fail and batteries die. 

That harsh environment presents a real challenge for NASA as it pursues a return of astronauts to the moon — especially to the south pole, which has some of the coldest temperatures in the solar system — but not an insurmountable one. 

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At Goddard Space Flight Center in Maryland, a team of engineers is testing a piece of equipment in a thermal vacuum chamber, putting the hardware through its paces. The chamber shifts from the extremes of 300 degrees Fahrenheit to -330 degrees Fahrenheit. Through repeated hot and cold cycles, the testing mimics real temperature swings that could happen between deep shadow and full sun at the lunar south pole, where Artemis IV may land with a crew as early as 2028. 

Based on test results, the Lunar Environment Monitoring Station, or LEMS, is expected to become the first U.S. instrument to survive a full polar night, a milestone for NASA's plan to build a long-term moon base in the treacherous region. 

"No one, no American payload, as far as we know, has ever been able to say that they have survived the lunar south pole during its lunar night and been functional," said Samantha Hicks, the lead systems engineer for LEMS. "We are on track to become the first U.S. payload to do that."

The LEMS device is a key piece of hardware for NASA's lunar ambitions, tracking how the ground shakes on the moon for up to two years. The suitcase-size box will keep a constant ear to the ground for moonquakes and asteroid strikes — not just at the lunar south pole, but around the entire moon. 

Perhaps surprisingly, the moon remains seismically active, despite its lack of plate tectonics like we have on Earth, said Naoma McCall, LEMS co-investigator and deployment lead. The Apollo missions more than 50 years ago placed similar seismometers on the moon and recorded deep and shallow tremors, thermal events, and meteoroid impacts. But those midcentury instruments shut down in 1977 and provided an incomplete picture of what's going on in the moon's crust and mantle, she said. 

More data is crucial for NASA to safely establish a lunar outpost for humans to live and work, especially if the polar region turns out to shake more often — or more strongly — than predicted.

"There's a lot we don't know about the lunar interior because we only had the observations from the near side," McCall said, referring to the lunar hemisphere facing Earth, where all Apollo missions landed.

For decades, many far‑flung space missions have stayed warm with small nuclear heat sources that slowly release energy as they decay. Those systems are powerful but rely on scarce fuel. Furthermore, they add cost, complexity, and safety reviews. If this small piece of equipment can ride out the lunar night using only sunlight, batteries, and insulation, NASA could replicate the model for faster and simpler surface gear in the future. 

To install LEMS, an astronaut will nestle the box in a trench and drill cylindrical holes nearby to bury two sensors under ground. Engineers designed the 66-pound box so one person could carry it. If that load still sounds too heavy, remember that everything on the moon feels about one-sixth lighter than it does on Earth. 

After making sure the system is pointed in the right direction, the astronauts can set it and forget it, McCall said. A team practiced deploying the equipment at the University of Central Florida, in a room full of artificial moon soil, to ensure it could be executed in simple steps. 

"We'll flip three switches and then walk away," McCall said.

While the outside of the box bakes and freezes, the most important internal components — the battery, autonomous computer, and other electronics — stay between about -22 and 86 degrees Fahrenheit. Engineers say that tighter internal range is what allows the equipment to continually operate, even as its shell faces the brunt of the lunar conditions.

The key to maintaining that consistent internal temperature is an advanced thermal blanket. The proprietary material, developed by Colorado-based Quest Thermal Group for NASA, is called Integrated MultiLayer Insulation, or IMLI. NASA also worked with partners to adjust how it will charge the lithium-ion battery to survive the extreme cold.

"Lithium ion absolutely hates going below -30 degrees [Celsius]. That's when you start getting lithium ion plating," said Hicks, referring to a problem that happens when the batteries can no longer absorb the chemical that carries the energy. "It's all about surviving that lunar night and worst-case scenario." 

After recent changes to the Artemis launch campaign, NASA has begun reworking the high-level plan for the upcoming moon-landing mission. The agency will decide whether the LEMS cargo will fly on Artemis IV after it has finalized the official list of everything onboard. In the meantime, the team will complete the rest of the testing schedule over the next few months.