Auburn aerospace engineering professor discusses significance of NASA’s discovery of water on moon

NASA sent shockwaves through the science and aerospace communities on Monday when it announced the discovery of water on the surface of the moon. Auburn Assistant Professor of Aerospace Engineering Toshi Hirabayashi discusses the significance of the discovery and talks about where it may have come from, what it may mean for the future of space exploration and perhaps even colonizing the moon.

What is the significance of this finding, and what does it mean in the grand scheme?

The moon has been considered to be very dry, but the findings from the recent papers show that water (ice) is more widely distributed on the moon than thought, at least on the top of the surface. Since lunar explorations started, researchers have been trying to capture the existence of water. The main techniques for searching for water molecules are remote sensing. They are powerful for inferring what types of materials exist on the top surface of the moon.

However, water is very tricky because it has been difficult to be identified uniquely. So, researchers “inferred” the existence of water molecules by using H or OH (hydroxyl), assuming that they are originated from water. The recent work used measurement of thermal emission at 6 µm, which is related to a direct signature due to water molecule vibration. The finding is promising that water is widely distributed over the moon.

Is there any indication this water is residual or a recent accumulation, and do scientists have any thoughts about what the source may be?

The source of water on the moon is still under active discussions. They may be brought by solar wind particle sputtering and impacts of comets and asteroids, as well as volcanic activities. Some also argue that the Earth’s atmosphere or ocean may have contributed to water on the moon. Currently, asteroid impacts are considered to be the most accepted scenarios, but how much they contributed is still unknown. OSIRIS-REx and Hayabusa2 are missions to explore this issue. 

Do you think this will affect/accelerate the country’s plan to return to the moon with an expedition in the coming years?

Yes, absolutely. The lunar science and engineering communities have been working on defining how we explore the moon. We have been working on addressing what questions need to be solved on the NASA/Artemis III program.

As an expert in aerospace engineering, how significant is this discovery for the aerospace industry, given that the SOPHIA is a flying observatory rather than a fixed telescope or one on a satellite orbiting in space?

I believe that each telescope has pros and cons. Combining all these elements would help observe objects far from us accurately.

What might this mean for the future of space exploration or perhaps colonizing the moon?

This would be the first step to better understand our neighbor and how we better understand the origin of the Earth-moon system and, thus, the origin of life and how we better use the lunar environment to expand our activities and frontiers.

Colonizing the moon is still a challenging issue. For example, how do you live there for a longer time scale? You may need infrastructures for power, food and social networks. The moon’s condition is much different from the Earth’s. Importantly, the finding suggests that water is likely stored in lunar grains and doesn’t suggest the existence of rivers. Additional studies must be performed.