NASA's Curiosity rover provided fascinating insight in the history of the Martian atmosphere by analyzing xenon, a heavy noble gas.
Noble gases do not react with other substances in the air or on the ground, which allows them to give an uncompromised account of the history of an environment, NASA reported. Despite its promise, xenon is found in frustratingly low quantities in the Martian atmosphere.
"Xenon is a fundamental measurement to make on a planet such as Mars or Venus, since it provides essential information to understand the early history of these planets and why they turned out so differently from Earth," said Melissa Trainer, one of the scientists analyzing the Sample Analysis at Mars (SAM) data.
The atmosphere of a planet is made up of numerous gases, which create different variants of chemical elements called isotopes; when the planet loses its atmosphere, these isotope ratios can be affected. Measuring xenon, which exists in nine different isotopes, can show which layers of Mars' atmosphere were stripped away.
The SAM measurement of the ratios of the nine xenon isotopes traced an extremely early period in Mars' history in which the atmosphere was rapidly escaping. During this period, the lighter isotopes were escaping more quickly than the heavier ones. These isotope ratios were first noticed in small amounts of Martian atmospheric gas trapped in meteorites that landed on Earth.
"We are seeing a remarkably close match of the in-situ data to that from bits of atmosphere captured in some of the Martian meteorites," said SAM Deputy Principal Investigator Pan Conrad.
The xenon Mars experiment took months of tedious testing in a chamber that simulated Mars' environment using the SAM data.
"I'm gratified that we were able to successfully execute this run on Mars and demonstrate this new capability for Curiosity," said Charles Malespin, who developed and optimized the sequence of instructions for SAM.
