Within about 12 hours of touching down on the lunar surface, Chang'e-4 also deployed its Yutu-2 rover, which is now studying the area immediately surrounding its landing site. Equipped with a ground-penetrating radar and onboard spectrometer, Yutu-2 aims to investigate the internal structure of the Moon, as well as the composition of the lunar soil, for as long as possible. Just recently, Yutu-2 carried out an analysis of rocks found within a young, small crater tucked in the larger South Pole-Aitken Basin. These samples contained a unique blend of minerals like olivine and pyroxene, which researchers say serves as strong evidence that the Moon once had a molten mantle below its crust.
Unlike the original Yutu rover, Yutu-2 has already exceeded its expected lifetime of three lunar days (or about three Earth months). As of late April, Yutu-2 had entered its fifth lunar day and had traveled a total of about 600 feet (180 meters), more than 50 percent farther than its predecessor. And although China has largely remained tight-lipped about science results from Chang'e-4, the data collected by the lander and rover are almost guaranteed to be studied for years to come.
Present satellites: Queqiao and Longjiang
As you may expect, landing on the far side of the Moon carries its own set of unique challenges; and one of the biggest is communication. Because the entirety of the Moon sits between Chang'e-4 and Earth, it's impossible for ground control to directly communicate with the lander. To overcome this hurdle, six months before the launch of Chang'e-4, China also launched a relay satellite named Queqiao.
Queqiao literally means "Magpie Bridge," which is a reference to a Chinese folktale called "The Cowherd and the Weaver Girl," in which a flock of Magpies link their wings to form a bridge across the Milky Way. By sliding the satellite into a halo orbit around the Earth-Moon L2 Lagrange point — a stable location where the gravitational pulls of the Earth and the Moon balance out — Queqiao is able to transmit data to and from anywhere on the far side's surface. Queqiao is the first lunar relay satellite to set up shop at this location.