Delicate extraction of gases from the time capsule from the surface of the moon
(ORDO NEWS) — Scientists at Washington University in St. Louis, USA, are helping extract gases for analysis from a container of lunar soil samples that astronauts collected from the surface of the Moon in 1972 and evacuated for storage. This new study became part of NASA‘s Apollo Next Generation Sample Analysis (ANGSA) program.
Astronauts of the Apollo 17 mission collected this sample of lunar soil from the site of an ancient landslide in the lunar Taurus-Littrow Valley.
The astronauts used a special tool to take a core of lunar regolith – a coarse mixture of dust, soil and rock fragments from the surface of the Moon – and sealed the sample in a container. Then on Earth, NASA sent the sample to storage at the Johnson Space Center, where it has remained in nearly pristine conditions to date.
“For 50 years, this sample of lunar soil was in a special vacuum container, which, in turn, was placed inside a second, outer vacuum container,” said Alex Meshik, professor at Washington University in St. Louis, who developed apparatus for extracting gases from these containers. “These containers are nested inside each other like Russian nesting dolls.”
These containers were sealed in two Teflon bags and remained until recently in a special repository of lunar samples in a nitrogen atmosphere.
The careful opening of these containers, carried out by Meshik and his colleagues last month, proved to be quite a challenge. It was necessary to be able to identify the original chemical nature of any individual gas or mixture that might be contained in the containers.
These include lunar gas that may have entered the containers during soil sampling from the Moon’s surface, as well as any other gases that may have leaked from rocks in subsequent decades while the material was in storage.
“There is no perfect vacuum flask,” Meshik said. “We cannot find out what happened to the vacuum flasks that isolated these samples for 50 years. How well did they hold the vacuum? What was the level of leakage? The main problem in building the extraction system was to anticipate all possible scenarios.”
“Therefore, our apparatus was designed to carry out not a single extraction, but several extractions of different volumes of gas under different conditions,” she said.
“In order to make informed decisions during these extractions, we equipped the instrument with a mass spectrometer for real-time analysis of the molecular composition of gases, as well as three precision capacitance manometers for non-destructive and gas pressure-independent measurements,” said Meshik.
Preliminary results of the study of the composition of this gas will be discussed at the Conference on the study of the moon and planets, which will be held in Houston from March 7 to 11.
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