In this series we are exploring NASA's top five challenges as detailed in its Civil Space Shortfall Ranking, which is basically NASA's Christmas wish list. These are the technologies that NASA believes we need to develop if we want to go to space…and stay there.
And finally, after multiple rounds of voting from NASA centers, industry partners, and academic researchers, the highest priority goal we need to accomplish to make all our space dreams come true: surviving the Lunar night.
Now I know this sounds like a low-budget knockoff of Five Nights at Freddy's, but it's the real deal. The Lunar night is no fun at all. For one, it typically lasts two weeks at a time (although there are some peaks that receive sunlight almost permanently, but there are also regions where the sun never strikes at all). For another, temperatures can plummet down to 35 degrees above absolute zero. This is absolutely unprecedented; there is no analogy to anything we have experienced on the Earth. Even in arctic regions, where the Sun can disappear for months at a time, are helped by the fact that we still have an atmosphere that can retain and distribute heat. When the Sun shines on the equator, some of that heat makes it up to the poles. But the Moon has no atmosphere, so the only heat you get is from the Sun. When it's gone, it's gone. This makes nighttime operations are a serious challenge. It's really hard to design electronics, and especially batteries, that can function for long periods of time at low temperatures, because almost all of our battery designs rely on chemical processes to generate electricity – processes that slow down at low temperatures, and all of our electronics are designed to work…you know, on Earth.
There has been some headway in the direction of surviving the lunar night. In early 2024 the Japanese lander SLIM, for Smart Lander for Investigating Moon, also known by the much cooler anime nickname of "Moon Sniper", made history by surviving three lunar nights – that's three four-week cycles of light and darkness. But to survive the nights the lander had to shut down and enter a hibernation state, hoping that its batteries would stay warm enough to power itself back up once daylight hit again.
So while that technically counts as surviving the lunar night, that's not exactly what NASA and its partners had in mind when they ranked this as their number one challenge. We can't just go into low-power sleep mode every two weeks, especially if we're talking about extended human or even robotic activities on the lunar surface.
Surviving the Lunar night means transitioning from a daylight temperature of over a blistering 120 degrees Celsius (or 260 degrees Fahrenheit) all the way down to -240 Celsius at night, which is…negative a lot in Fahrenheit. On the other side of the coin, our own robotics and electronics are going to generate their own heat, anywhere from 5 Watts to 10,000 Watts. We need to efficiently manage that heat and make sure it doesn't warp or destroy other vital components on its way out of the spacecraft, especially when the outside temperatures will vary so much.
What will it take to enable lunar night operations? We need components that can manage those kinds of massive temperature swings and still efficiently operate in frigid conditions. We need systems that can efficiently dump heat in both freezing and boiling outside conditions. We need large solar panels that can absorb energy during the daytime and low-temperature batteries that can continue to supply that power through the night. We can't just have these components specialized to one temperature extreme or the other – they need to be able to handle both.
I see this challenge as the culmination of all the other ones. Surviving the lunar night isn't easy, but it serves as a critical milestone in our advance into space. If we want to survive the lunar night and maintain activities and exploration for those two weeks of darkness, we need to solve the other four challenges. This will be our true test. We can't just content ourselves with literal day-trips or low-power night modes. We have to be able to maintain the same level of activity regardless of the daylight conditions. We need high-powered, capable robotics. We need reliable systems for timing and navigation. We need more sophisticated computers, and most importantly we need a lot of electricity. If we can maintain robotic or crewed activities through lunar night after night, then we will have the technological base we need to create a more robust presence on the Moon and extend even further into the solar system.
It won't be easy. The lunar night is unforgivingly cold, depressingly dark, and depressingly long. But hey, at least we'll get a great view of the stars.
