Leonard David's INSIDE OUTER SPACE

Chang’e-4 lander and Yutu-2 rover. Images of each other taken by the respective machinery.
Credit: CNAS/CLEP

The super-camera system on NASA’s Lunar Reconnaissance Orbiter (LRO) continues to monitor the whereabouts and wanderings of China’s Yutu-2 rover on the Moon’s farside.

The Chang’e 4 rover, Yutu-2, moved between February 1, 2019 and February 28, 2019. The upper left panel shows the landing site before Chang’e-4 set down and the image in upper right panel has the best resolution of the lander and rover taken so far. The lower left image was taken six hours later with a slew angle of 40°. The most recent view in the lower right shows that Yutu-2 traversed 150 feet (46 meters) to the west during the month of February.
Credit: NASA/GSFC/Arizona State University

Over the next few months, the Sun will rise higher and higher over the landing site when LRO is overhead, providing the opportunity to obtain images with no shadows, according to Mark Robinson, principal investigator of LRO’s Lunar Reconnaissance Orbiter Camera (LROC) system — three cameras mounted on the LRO that capture high resolution photos of the lunar surface.

Blast zone

Those upcoming images will be particularly useful for mapping differences in brightness (albedo), Robinson notes, and researchers should get the first real look at the “blast zone”- the region that was brightened around the Chang’e-4 lander as rocket exhaust interacted with the regolith, as seen around all other landing sites.

The tracks of the rover should also be visible in the coming months, allowing researchers to follow Yutu-2’s exact path along the floor of Von Kármán crater during its exploration of the lunar farside, Robinson explains.

NASA’s Lunar Reconnaissance Orbiter (LRO).
Credit: NASA/Goddard Science Visualization Studio (SVS)

China’s Chang’e-4 mission landed in Von Kármán crater within the South Pole-Aitken Basin on January 3, 2019.

Westward progress

LRO passes over any given place on the Moon at least once every month (in the daylight), allowing the westward progress of the Yutu-2 rover to be seen.

Image of Mons Tai, a hill near “Statio Tianhe”, the landing site of China’s Chang’e-4 lunar probe.
Credit: CNSA

Robinson explains that, at the end of February, Yutu-2 was 226 feet (69 meters) from its home base, the Chang’e-4 lander; LROC images show Yutu-2 made 150 feet (46 meters) of westward progress during the month of February.

Each month when LRO images the landing site, now called Statio Tianhe, the lighting changes, providing a different view of the surface.

During times near dawn or dusk, Robinson says, long shadows enhance topography and closer to noon differences in surface brightness are more apparent. In the latest image from February 28, the Sun is near the horizon and the lander and rover each cast long shadows.