As multiple nations plot out their moon exploration strategies, how best to survive the lunar night gives space engineers sleepless nights.

At most locations on the moon's surface, there are fourteen Earth days of continuous sunlight followed by fourteen days of darkness and cold.

The lunar surface can get as cold as minus 180 C during the night due to the lack of a cooling atmosphere. The permanently shadowed regions on the moon can plunge down to minus 400F.

It is the first step in returning astronauts to the moon.

Pluses and minuses

One of the most challenging environmental challenges that future moon expeditions will face is the addition of all those pluses and minuses. Coming to grips with the moon's vicious environment will be required if you want to gain longer and longer human stays.

Water ice can be found in craters on the moon in which the sun is not shining. The deposits are ideal for processing into a wide range of things.

At the lunar south pole, loaded with PSRs, there is a rich place for harvesting water ice.

It is not easy in this cold weather.

The warm pits on the moon might be the most pleasant place for astronauts.

Shown here is a rendering of 13 candidate landing regions for NASA's Artemis 3 mission. Each region is approximately 9.3 by 9.3 miles (15 by 15 kilometers). A landing site is a location within those regions with an approximate 328-foot (100-meter) radius.

Shown here is a rendering of 13 candidate landing regions for NASA's Artemis 3 mission. Each region is approximately 9.3 by 9.3 miles (15 by 15 kilometers). A landing site is a location within those regions with an approximate 328-foot (100-meter) radius. (Image credit: NASA)

Basic problem, two branches

Dean Eppler, chief lunar scientist at TheAerospace Corporation, said that surviving the night on the moon is a key issue for a lunar south pole site.

The basic problem has two branches according to Eppler. Simple survival during the lunar night, and operations during night time, regardless of whether it's a 'normal' day night cycle like you would get at anywhere other than the poles, and the variable darkness you get at the poles because of the low solar inclination angle.

For future missions, particularly for landed missions off the polar latitudes, hunkering down may still be the best decision.

"You don't do field geology at night," Eppler said, "but that will probably be the time to do inside activities, such as life sciences." He said those are mostly not done during the day when crew members are on the moon.

He's optimistic about taking on the moon. We've considered lunar exploration before, but we're better equipped to handle that now.

Artistic depiction of NASA astronauts at the lunar south pole carrying out early work to establish an Artemis Base Camp.

Artistic depiction of NASA astronauts at the lunar south pole carrying out early work to establish an Artemis Base Camp.  (Image credit: NASA)

Profoundly cold

Eppler sees a bigger problem with the poles. The areas that get shadowed by the terrain will get very cold, but not as cold as the equator.

"We'll have to deal with the problems of working in areas that are still shadowed much of the time, long enough to be profoundly cold inside of them." It's a huge challenge and I think we'll need a special set of tools that we only use in cold conditions.

Keep-alive warmth

Philip Metzger is a planetary scientist with the Florida Space Institute at the University of Central Florida.

Even a small amount of energy and good insulation can keep the car warm. Even when it was far away from the sun, the electronics were kept at a cool temperature.

Where can we find the energy on the moon?

One example is the use of radioactive decay sources. Radioactive Heater Units can be put on the vehicle at any time. It is more difficult without a radioactive source.

A stand-alone asset that has adequate battery capacity would be ideal. Through the night, a rover could be plugged in. The asset will run out after the sun rises. It would take some mass on the moon for adequate storage, but with the new lunar landers, it should be easy to do.

Using local resources on the moon can help make future crewed missions more sustainable and affordable.

Using local resources on the moon can help make future crewed missions more sustainable and affordable. (Image credit: RegoLight, visualization: Liquifer Systems Group, 2018)

Good set of assumptions

Key temperature data on the moon is yielding present-day data, according to Noah Petro. The LRO mission is circling the moon.

The data from the Diviner instrument on LRO gives us a great set of bounding conditions for what to expect at the poles. Petro said that they knew the expected cold temperatures at night and warmth during the day from the data.

Petro believes that the issue of lunar survival can be traced back to an already mature understanding of the engineering requirements to operate through lunar nights.

Apollo 17's surface time, the program's longest stay time on the Moon was three days, two hours, fifty-nine minutes. Photo shows Apollo 17's Jack Schmitt carrying a gnomon back towards the lunar rover after observing and sampling the east side of a huge boulder. The vertical arrow in the distance points to the Lunar Module Challenger, located roughly 2 miles (3.1 kilometers) away.

Photo shows Apollo 17's Jack Schmitt carrying a gnomon back towards the lunar rover after observing and sampling the east side of a huge boulder. The vertical arrow in the distance points to the Lunar Module Challenger, located roughly 2 miles (3.1 kilometers) away. Apollo 17's surface time, the program's longest stay time on the Moon was three days, two hours, fifty-nine minutes. (Image credit: NASA)

Message from Apollo

There are lessons to be learned from the 20th century Apollo era, according to Clive Neal, a lunar exploration expert at the University of Notre Dame.

The Apollo lunar surface experiments package consisted of scientific instruments set up by moonwalkers at the landing site of each of the five Apollo missions to land on the moon.

The issue is if solar is the way to go. Is it possible to use battery technology during the lunar night?

It's not good enough to just survive the night. I think we need to match what was done 50 years ago.

A close-up view of two components of the Apollo Lunar Surface Experiments Package (ALSEP) deployed by Apollo 14 astronauts during their first moonwalking excursion.

A close-up view of two components of the Apollo Lunar Surface Experiments Package (ALSEP) deployed by Apollo 14 astronauts during their first moonwalking excursion. (Image credit: NASA/JSC)

Moonwalking suits

What will it be like to work on the moon?

The thermal design issues will be severe when it comes to moonwalking suit systems, including boots, gloves and the backpack-like portable life support system.

If you stand ankle deep in a shadowed area, your legs, torso, etc., are in the sun. Ensuring that the boots and pressure garment material don't freeze and break, as well as ensuring that the upper parts of the suit system don't become so hot, is a significant issue. The problem is real.

According to Eppler, Artemis technologists are trying to come to terms with the fact that they are in the dark.

It says to me that we will find a solution at some point. When people don't understand or accept the magnitude of the problem, it's when you get into trouble.

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