A radar sounder aboard China’s Yutu lunar lander has detected evidence of at least nine distinct layers of subsurface rock, indicating the moon is more complex than previously believed.
Yutu (which is Chinese for Jade Rabbit) studied its landing site in the northern crater known as the Mare Imbrium or “Sea of Showers” using four geoscience instruments, including a wide-field camera, a visible-infrared imaging spectrometer, an X-ray spectrometer, and ground-penetrating radar, according to reports published Friday by the website Sky and Telescope.
Shedding light on the contents of the lunar mantle
A new paper published this week in the journal Science reveals the discovery of a surprisingly complex geological history at Mare Imbrium. The deepest of the nine layers are from lava that flowed over the region 3.3 billion years ago, the researchers discovered, and above it is a series of flows that the team believes are 2.5 billion years old, the website added.
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Long Xiao, a researcher at the China University of Geosciences in Wuhan and lead author of the new study, told Space.com, “Two things are most interesting. One is more volcanic events have been defined in the late volcanism history of the moon. Another is the lunar mare [volcanic plain] area is not only composed of basaltic lavas, but also explosive eruption-formed pyroclastic rocks.” That discovery “may shed light on… the volatile contents in the lunar mantle.”
Red rover, red rover
The lunar rover was part of China’s Chang’e 3 moon mission, which in December 2013 became the first spacecraft to make a soft landing on the moon since 1976. Yutu was able to travel a distance of 374 feet (114 meters) before a technical issue ended its journey last January. Using its ground-penetrating radar and its camera, the rover was able to probe to depths of 1,300 feet (400 meters) and created a detailed picture of the Chang’e 3 landing site.
Studying the ground beneath it as it travelled, Yutu characterized the craters that it drove past and investigated an unusually coarse, 13-foot by five-foot (4 meter by 1.5 meter) rock known as Loong. Based on the sum total of the rover’s research, the scientists concluded that the make-up of the Mare Imbrium is vastly different from areas of the moon visited by the US and Russia.
Original plans called for the rover to travel up to six miles (10 kilometers) over a three-month span, but those plans were shuttered after a malfunction prevented its solar-cell panels from closing and helping keep its interior insulated during the lunar nighttime. However, as Sky and Telescope noted, the lander “made the most of its limited mobility” and brief data-collection opportunity.
While those mechanical issues brought Yutu’s mission to a premature end, preventing it from transmitting any future data, Xiao told Space.com that more discoveries would be coming soon. “Our report only provides the scientific results based on imagery and radar data,” he explained, promising results from the Visible Near-Infrared Spectrometer (VNIS) and the Active Particle-Induced X-ray Spectrometer (APXS) instruments “for composition study will come out soon.”