10:45 AM - 11:00 AM
[AOS14-07] Possibility of water in vertical holes near the lunar polar regions and lunar habitation
★Invited Papers
Keywords:Lunar pit, Water, Space Habitat, ECLSS
1. Research Background
The Artemis program will focus on exploring the south pole of the moon. There are two concerns: 1. The existence of water ice in the permanent shade of the polar region has not been confirmed. 2. The permanent shade is on the order of kilometers away from the point where sunlight is available. Therefore, we will focus on the lunar vertical holes and underground cavities that exist in the polar regions, and investigate the water ice that grows by vapor phase in the permanent shade of the underground cavities and the distance between the sunlit area and the permanent shade.
2. Research Aims and Target Values
1. We aim to be able to predict the amount of water ice to some extent based on the latitude and depth of the underground cavity. 2. We will consider concrete examples of Japan's own exploration and lunar utilization within the scope of the Artemis program. 3. Regarding the exploration and utilization of the lunar vertical holes discovered by Japanese people, we will focus on the advantage of the adjacent sunlit area and permanent shade, and the accumulation of water ice, and will begin research before anywhere else in the world.
3. Image of the exit after the research period is over
If there is a high possibility that water is buried in the vertical holes and underground cavities in the polar regions, we will propose to domestic and international ISRU (In-Situ Resource Utilization) teams regarding the investigation of volatile substances in the vertical holes in the polar regions and start a joint operation.
4. Research Method
By conducting numerical simulations using a model simulating the underground cavities of the moon, we examined the possibility of the existence of water molecules in the underground cavities. We identified the distance between the vertical hole and the sunlit area. We exchanged opinions with the Low Temperature Research Institute of Hokkaido University and investigated the vapor phase growth of water ice at extremely low temperatures.
5. Achievements
From literature research, we clarified the difference in the loss rate of water ice depending on latitude and shape, and found the conditions under which water molecules can exist stably in underground cavities. In a cavity with a depth of 100 m, if it exists north or south of latitude 78 degrees, water molecules will be adsorbed to rocks. We will conduct route finding by land from the expected landing site to the vertical hole in the polar region. Survey of daylight hours and nighttime hours near the polar vertical hole → There was a 50% sunshine area nearby. We referred to overseas examples for the method of exploring inside the polar vertical hole and the consideration of a robot rover for exploring the vertical hole.
6. Research results and discussion
Recognizing that permanent shadows change over billions of years, we considered new landing site candidates.
We will proceed with route finding to the polar vertical hole by land from the expected landing site. We will also open Quickmap (https://quickmap.lroc.asu.edu/), a tool that can investigate maps of the moon, and aim to analyze the sunshine rate even when the following three layers are imported.
・Sun Visibility (60m/120m/240m)
・Pit Locations
・A3: Candidates Landing Regions 2022 (13 candidate landing sites for Artemis)
Progress ②: Regarding the investigation of daylight hours and nighttime hours near the vertical holes in the polar regions, we referred to the materials of the Lunar Planetary Exploration Data Analysis Group. We were able to investigate the average sunshine rate around Schomberger A1. Unfortunately, it seems that the sunshine hours do not reach 14 days (sunshine rate of 50% or more). However, it was found that a short distance away from Schomberger A1, there is a sunshine rate of 45%-50% (a place where the sunshine hours are close to 14 days) a few hundred meters away.
The Artemis program will focus on exploring the south pole of the moon. There are two concerns: 1. The existence of water ice in the permanent shade of the polar region has not been confirmed. 2. The permanent shade is on the order of kilometers away from the point where sunlight is available. Therefore, we will focus on the lunar vertical holes and underground cavities that exist in the polar regions, and investigate the water ice that grows by vapor phase in the permanent shade of the underground cavities and the distance between the sunlit area and the permanent shade.
2. Research Aims and Target Values
1. We aim to be able to predict the amount of water ice to some extent based on the latitude and depth of the underground cavity. 2. We will consider concrete examples of Japan's own exploration and lunar utilization within the scope of the Artemis program. 3. Regarding the exploration and utilization of the lunar vertical holes discovered by Japanese people, we will focus on the advantage of the adjacent sunlit area and permanent shade, and the accumulation of water ice, and will begin research before anywhere else in the world.
3. Image of the exit after the research period is over
If there is a high possibility that water is buried in the vertical holes and underground cavities in the polar regions, we will propose to domestic and international ISRU (In-Situ Resource Utilization) teams regarding the investigation of volatile substances in the vertical holes in the polar regions and start a joint operation.
4. Research Method
By conducting numerical simulations using a model simulating the underground cavities of the moon, we examined the possibility of the existence of water molecules in the underground cavities. We identified the distance between the vertical hole and the sunlit area. We exchanged opinions with the Low Temperature Research Institute of Hokkaido University and investigated the vapor phase growth of water ice at extremely low temperatures.
5. Achievements
From literature research, we clarified the difference in the loss rate of water ice depending on latitude and shape, and found the conditions under which water molecules can exist stably in underground cavities. In a cavity with a depth of 100 m, if it exists north or south of latitude 78 degrees, water molecules will be adsorbed to rocks. We will conduct route finding by land from the expected landing site to the vertical hole in the polar region. Survey of daylight hours and nighttime hours near the polar vertical hole → There was a 50% sunshine area nearby. We referred to overseas examples for the method of exploring inside the polar vertical hole and the consideration of a robot rover for exploring the vertical hole.
6. Research results and discussion
Recognizing that permanent shadows change over billions of years, we considered new landing site candidates.
We will proceed with route finding to the polar vertical hole by land from the expected landing site. We will also open Quickmap (https://quickmap.lroc.asu.edu/), a tool that can investigate maps of the moon, and aim to analyze the sunshine rate even when the following three layers are imported.
・Sun Visibility (60m/120m/240m)
・Pit Locations
・A3: Candidates Landing Regions 2022 (13 candidate landing sites for Artemis)
Progress ②: Regarding the investigation of daylight hours and nighttime hours near the vertical holes in the polar regions, we referred to the materials of the Lunar Planetary Exploration Data Analysis Group. We were able to investigate the average sunshine rate around Schomberger A1. Unfortunately, it seems that the sunshine hours do not reach 14 days (sunshine rate of 50% or more). However, it was found that a short distance away from Schomberger A1, there is a sunshine rate of 45%-50% (a place where the sunshine hours are close to 14 days) a few hundred meters away.