A European experiment aboard China’s Chang’e 6 mission registered previously undiscovered charged particles on the moon’s surface, a catalog of which allows astronomers to better study the chemical composition of the moon’s regolith.
These particles, which are essentially gases excited by sunlight, were found at the landing site of the Chang’e-6 spacecraft in the southern pocket of Apollo Crater, which is located in the South Pole-Aitken Basin on the far side of the Moon. The ion detector was the first European Space Agency lunar lander.
“This was ESA’s first activity on the surface of The moona world first scientific and first lunar collaboration with China,” said Neil Melville, ESA’s technical officer for the experiment, in statement. “We collected a quantity and quality of data far exceeding our expectations.”
While The Earth is protected from solar storms thanks to its magnetic field, which repels and captures charged particles from the sun, the moon lacks its own magnetic field. So the gases in its vanishingly thin atmosphere—helium, ammonia, methane, and carbon dioxide, among a handful of others—are easily ionized by sunlight and “taken up” by flowing plasma. These charged particles carry information about the chemical composition of the lunar regolith, from which the gases originate through various processes spread across the surface, including impacts from small asteroids.
Connected: Watch China’s Chang’e 6 probe land on the far side of the moon in dramatic video
In 2012, a NASA lunar mission called ARTEMIS (short for Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon’s Interaction with Sun and not to be confused with the agency’s modern Artemis lunar program) observed ion uptake rising 12,400 miles (20,000 kilometers) above the lunar surface. They are all positive ions, which means they contain more protons than electrons. Negative ions are short-lived and do not drift far from the surface, so they were never detected before the Chang’e-6 experiment, the scientists said.
Scientists have not yet come to an estimate of how many negative ions float near the moon’s surface, a number that would have implications for how the moon interacts with the sunAccording to Swedish Institute for Space Physicswho created the ion detector called the Negative Ions on the Lunar Surface (NILS).
NILS began operating nearly five hours after the spacecraft landed on the moon on June 1. It operated intermittently during the two-day mission, experiencing power lows, communication failures and reboots, the ESA said. The detector collected a total of three hours of data – three times the amount needed to consider the experiment a success.
“We alternated between short bursts of full power and long cooldown periods because the instrument was heating up,” Melville said in the statement. “The fact that it stayed within its thermal design limits and was able to recover in extremely hot conditions is a testament to the quality of the work done by the Swedish Institute of Space Physics.”
In addition to the NILS experiment, the Chang’e 6 mission penetrated the surface of the moon and retrieved about 2,000 grams of material. Scientists say these samples, the first ever collected from the far side of the Moon, could offer fresh insights into the formation and evolution of the Moon and solar system.
After sampling was complete, the robotic lander placed a wooden model the five-starred red flag of China on the surface before lifting off and rendezvousing with a waiting spacecraft in orbit.
As of Wednesday (June 12), the samples have continued to orbit the moon in the Chang’e 6 return module, awaiting the correct time to begin its journey back to Earth. The return capsule is scheduled to arrive on June 25 at Siziwang Banner in northern China’s Inner Mongolia Autonomous Region.
