For 50 years geologists have been slicing slivers off the Apollo missions' lunar rocks for analysis, making many important discoveries in the process. Two samples, however, have remained sealed in a vacuum all that time. Now, NASA has opened one. The superstitious might see this as a dangerous move, equivalent to opening a cursed tomb or other bad omens, but NASA is above such irrational fears, and anyway, how much worse could 2022 get?
When the six Apollo missions to make lunar landings returned with their rocks there was a brief flurry of important analysis. As the technology with which we could study rocks advanced, discoveries that could not have been made at the time trickled out. Unfortunately, however, any gasses that may have been trapped in pockets within the lunar material would have escaped in the time most samples have been stored on Earth, denying us the chance to examine them with modern equipment.
The exception, scientists hope, are two samples placed in sealed tubes on the Moon and not opened since. One of these, returned by Apollo 17 (the last crewed mission to the Moon) has now been opened.
"For the last 50 years, the lunar core was enclosed in a core sample vacuum container, which was then enclosed in an outer vacuum container," said Professor Alex Meshik of Washington University in St Louis in a statement. All this was put inside sealed Teflon bags, which in turn was put in a nitrogen box inside a vault to protect it from Earth's atmosphere, light, or even scientists keen to get the jump on colleagues.
Meshik is part of the team designated by NASA to open the sample very, very carefully in the hope of determining if any gas is present, and if so whether it is original lunar material, or has seeped in since, despite everything that was done to prevent that.
"There is no perfect vacuum seal," Meshik said. "There was no way to know how the vacuum seals on the containers fared after 50 years. Did they hold the vacuum? To what extent did they leak?” The extraction process was designed to deal with a range of different leakage scenarios, which added layers of complexity to the task. In the worst-case scenario we may learn nothing about lunar conditions, but will at least be taught a lesson on the failure of sealing mechanisms.
Molecules loose in the containers have been collected, after which the rocks will be observed to see if any gasses still trapped in the rocks will escape. Both initial and subsequent samples will be put through the world's most sophisticated mass spectrometers.
We will have to wait weeks for all potential gasses to diffuse, and months for peer-reviewed results, but when they come out they will include comparisons with another sample collected at the same site, but not stored in this way.
Jokes about 2022 not being the year for risks aside, there is a reason for the timing of the opening. “Understanding the geologic history and evolution of the Moon samples at the Apollo landing sites will help us prepare for the types of samples that may be encountered during Artemis,” NASA's Thomoa Zurbuchen said in a blog post.
The work will show whether even more protection is required for the Artemis mission to seal samples for the sake of future generations of researchers. It may also have application for storing Martian rocks.
The Apollo missions landed at widely separated sites in the hope of capturing the Moon's diversity, although they missed the poles, now thought likely to have subsurface water ice. The preserved sample came from an ancient landslide in the Taurus-Littrow Valley, in the 3.8 billion-year-old mountains around Mare Serenitatis. The material had been buried deep enough that even during the long lunar day its temperature would never have exceeded 0º C, increasing the chances gasses would remain trapped inside.