One of the designers of the Chinese lunar rover Yutu said in a news interview today that the rocky nature of the Moon’s surface, far rougher than expected, was what caused it to stall.
The rover was tested in Beijing, Shanghai and the desert in northwestern China before its launch, but the terrain of the landing site proved to be much more rugged than expected, said Zhang Yuhua, deputy chief designer of the lunar probe system for the Chang’e-3 mission. “It is almost like a gravel field.”
Data from foreign researchers projected that there would be four stones, each above 20 cm, on average every 100 square meters, but the quantity and size of the stones that Yutu has encountered has far exceeded this expectation, Zhang said in an exclusive interview with Xinhua. “Experts’ initial judgement for the abnormality of Yutu was that the rover was ‘wounded’ by colliding with stones while moving,” she said. [emphasis mine]
The implication of the highlighted quote is that it isn’t their fault, it was the fault of those evil Americans and Russians who incorrectly estimated the roughness of the ground. This article also doesn’t fit the information released when Yutu first stalled, where they explained that their problem was partly an inability to retract equipment in preparation for lunar night. While this story could be true, it isn’t the whole story.