Volatiles in Cold Traps , A Key to Understanding the Moon's Dark Craters

While astronomers and scientists are preparing for Martian missions this year, planetary scientists presented new information on the chemicals trapped in the dark craters of our moon. These new insights can help researchers determine whether or not these chemicals can be used for future missions to the moon. 

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To understand why the moon has dark areas, it is important to understand its axis. Unlike Earth which tilts its axis while moving around the Sun (this phenomenon causes the change in seasons), the moon stays put and this is why there are areas that are permanently in the dark (literally speaking) and some of these areas have craters which scientists call the cold traps.

WHY IS IT NECESSARY TO REACH THESE DARK PLACES IN THE MOON?

Craters are often made by an asteroid impact billions of years ago and since comets are composed of various compounds like carbon dioxide, methane, and even water vapor, these chemicals -- collectively known as volatiles -- could have been trapped in the moon's dark craters for a long time and this is what planetary scientists would like to harvest. In the recent convention of the American Geophysical Union Dana Hurley, a planetary scientist from the John Hopkins University proposed that understanding these volatiles and the cold traps can be helpful in determining potential resource. She also explained that if ever harvested, humans on lunar missions can consume water and use methane for fuel. 

However, this will not be an easy task. To be able to study cold traps and identify volatiles, one must need to deal with the darkness. For the longest time, astronomers were only able to study the cold traps using the Lunar Reconnaissance Orbiter which, in turn, has been measuring faint ultraviolet light from stars and hydrogen in space and reflects off these cold traps. Last year, planetary scientists were able to examine the reflection data from the moon's Faustini crater and found an abrupt change in the reflection that corresponds to ice which they previously thought suggested the presence of carbon dioxide.

"For every carbon dioxide molecule that you release somewhere on the moon, what percentage of those make it to the cold traps and stay there? Hurley asked and this is the question that she used as a foundation of her hypothesis of the reflected unknown volatile was, indeed, carbon dioxide. 

Hurley developed a model which was called the Monte Carlo simulation where she used the size and temperature data gathered by NASA's Lunar Reconnaissance Orbiter to be able to provide a probabilistic analysis of how much carbon dioxide will make it to the cold trap. She said that her methodology includes simply releasing particles and following them on trajectories and calculated the likelihood of these volatiles being broken down by sunlight before reaching a cold trap. 

With this methodology, she was able to predict that only 15-20% of the carbon dioxide released on the moon will end up in a cold trap and this is quite a surprising result especially since the percentage is higher than previous predictions and the relatively small surface areas of these cold traps. Hurley plans to do the same experiment, this time to determine the percentage for methane and carbon monoxide.