Future human explorers on the moon may have 99 problems, but staying warm or cold will be no problem. A team led by UCLA planetary scientists has discovered shady spots inside the moon’s craters that always hover around a comfortable 63 degrees Fahrenheit. The pits and caves they may lead to would make safer, more thermally stable base camps for lunar exploration and long-term habitation than the rest of the lunar surface, which heats up to 260 degrees during the day and drops to 280 degrees below zero at night.
Pits were first discovered on the moon in 2009, and since then scientists have wondered if they led to caves that could be explored or used as shelters. About 16 of the more than 200 pits are likely collapsed lava tubes, said Tyler Horvath, a doctoral student in planetary science at UCLA who led the new research. Two of the most prominent pits have visible overhangs that clearly lead to some kind of cave or void, and there is strong evidence that the overhangs of others may also lead to a large cavern.Lava tubes, also found on Earth, form when molten lava flows under a field of cooled lava or crust forms over a river of lava, leaving a long hollow tunnel. If the ceiling of a solidified lava tube collapses, a pit will open that can lead into the rest of the cave tube.
Horvath processed images from the Diviner Lunar Radiometer Experiment a thermal imaging camera and one of six instruments on NASA’s Lunar Reconnaissance Orbiter to see if the temperature in the pits differed from the temperature on the surface. Horvath and his colleagues focused on a roughly cylindrical 100-meter-deep depression about the length and width of a football field in an area of the moon known as Mare Tranquillitatis and used computer modeling to analyze the thermal properties of the rock and lunar dust and map pit temperatures over a period of time.
The results, recently published in the journal Geophysical Research Letters, revealed that temperatures in the permanently shadowed reach of the pit fluctuate only slightly during a lunar day, staying around 63 degrees. If a cave extends from the bottom of the pit, as the Lunar Reconnaissance Orbiter Camera images suggest, it too would have this relatively comfortable temperature.
The research team, which also included UCLA planetary science professor David Paige and Paul Hayne of the University of Colorado Boulder, believes the shadow overhang is responsible for the constant temperature, limiting how hot things get during the day and preventing heat from radiating. night. Meanwhile, the sun-heated part of the bottom of the pit reaches a daily temperature close to 300 degrees, which is about 40 degrees hotter than the surface of the moon.”Because the Tranquillitatis pit is closest to the lunar equator, the illuminated floor at noon is probably the hottest place on the entire moon,” Horvath said.
A day on the Moon lasts nearly 15 Earth days, during which the surface is constantly bombarded with sunlight and is often hot enough to boil water. The unimaginably cold nights also last about 15 Earth days. Inventing a heating and cooling device that can operate under these conditions and produce enough energy to power it continuously could prove an insurmountable obstacle to lunar exploration or habitation. Solar power—NASA’s most common form of power generation—doesn’t work at night, after all. (NASA currently has no plans to establish an exploratory base camp or habitation on the moon.)
Building bases in the shaded parts of these pits allows scientists to focus on other challenges, such as growing food, providing oxygen for astronauts, gathering resources for experiments, and expanding the base. Pits or caves would also provide some protection from cosmic rays, solar radiation, and micrometeorites. Humans evolved in caves and we can go back to caves when we live on the moon,” said Paige, who leads the Diviner Lunar Radiometer Experiment.
Diviner has been mapping the Moon continuously since 2009, creating NASA’s second-largest set of planetary data and providing the most detailed and comprehensive thermal measurements of any object in our Solar System, including Earth. The team’s current work on lunar pits improved the data from the Diviner experiment.”Because no one else was looking at things that small with Diviner, we found that it has a bit of double vision, which makes all our maps a bit blurry,” Horvath said. The team worked to align the many images taken by the instrument until they achieved an accurate thermal reading down to the single-pixel level. This process produced much higher resolution maps of the lunar surface.
Data from the early stages of this lunar crater thermal modeling project were used to develop a rover temperature control system for NASA’s proposed Moon Diver mission. Horvath and Hayne were part of the science team for this mission, which aims to have the rover abseil into the Tranquillitatis crater to examine the layers of lava flows seen in its walls and explore any existing caves.Horvath and Paige are members of the science team for a new lunar thermal camera led by Paul Hayne called L-CIRIS, which will head to the moon’s south pole in late 2023 to acquire the first ground-based thermal images.
For more read: https://www.sciencedaily.com/releases/2022/07/220726160213.htm
