Here’s a summary at The Planetary Society of the Chinese Chang’e 3 lander and Yutu rover mission accomplishments and status: Yutu Update – The Planetary Society.

But the rover did not arrive at the crater, or even reach the lander. It stopped as it was getting close to the lander, apparently because the electronics associated with moving its wheels and solar panels, so probably an important central control unit, failed at that point. I don’t know when it stopped, but the map shown at LPSC is instructive. It shows the daily stops between drives (the rover was only operated when in direct contact with China, for at most half a day at a time), and counting them suggests the fault occurred in the middle part of the day, possibly due to excessive heating which might have been exacerbated by dust buildup on the rover body. But this is conjecture, as I don’t know that each stop occupied only one day.

At any rate, it soon became apparent that the rover could neither move nor fold itself up to protect against the cold of the night. Enormous efforts were made to overcome this, to no avail. As night approached the problem was made public, most memorably by the rover’s Twitter alter-ego itself. Meanwhile the lander continued operating, and I’ll come back to that later. Sunset, and possibly the end of Yutu’s short life, came on 25 January. After a seemingly interminable wait the sun rose again, and a few days later on 12 February both lander and rover woke up. Yutu was more robust than expected. All its instruments, even the fragile cameras, were fine, but it couldn’t move. I don’t know if the lack of movement extends to the robotic arm with the APXS. The instruments may work, but future science would be very limited if the NIR spectrometer and the ground-penetrating radar are limited to always making the same observation.

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