Finally, China has released some tangible information on the state of its Yutu Moon rover through official state media channels. The results are encouraging, given the fact that we feared Yutu was in a totally useless state. The long period of absolute silence by the Chinese gave weight to this theory.

According to Xinhua, China's state media agency, Yutu's "radar, panorama camera and infrared imaging equipment are functioning normally". This holds the promise of more scientific data being returned from the rover. It also shows that the sub-systems required to operate these payloads, such as power and telemetry systems, also work.

But Yutu has other problems. Decoding the vague language that China has used in past (and more recent) media statements suggests that there is a mechanical control problem with the rover's mobility. It seems that Yutu either cannot drive well or cannot drive at all.

This is a surprise. This analyst originally expected that Yutu would be able to move but not operate some of its more fragile scientific instruments. In reality, it seems that the opposite is true.

This provides insight into the toughness of the instruments and the type of problems experienced by the rover. We were led to believe that a solar panel failed to fold inwards to protect the rover during the lunar night, suggesting a mechanical problem with its hinge mechanism. Have there also been mechanical problems with the wheels?

This is highly plausible. The wheels are in direct contact with the lunar surface. They are exposed to lunar dust, which is highly abrasive and electrically charged. It is possible that lunar dust has jammed some of the wheels or mechanisms associated with the wheels.

So, what can a stationary rover do? It can still take images, and the changing angle of the sun will provide differences in the appearance of the terrain. The infrared camera will be especially useful for such observations, watching how rocks deal with heat transfer. The radar can probably send a few pulses to the ground beneath it, but its usefulness has been compromised.

It cannot move to take observations at different locations, meaning that successive uses of the instrument would produce no new data. Of course, that assumes the terrain beneath it doesn't change, but this assumption is fairly solid.

It would seem that all of the aforementioned scientific tasks have been performed with Yutu in recent times. But will Yutu be of any further use, even in this stationary mode? We will need to wait longer to find out.

Yutu has again entered another two-week lunar night. Will it survive this next ordeal of frigid darkness? We don't know. Some instruments and parts that survived the last lunar night may not be functional at the end of this one.

It's disappointing to watch Yutu's problems, but we cannot ignore the benefits. China is gaining some solid engineering data on how its hardware performs under actual conditions. Some things work better than others. This was one of the main goals of the mission, and in that regard, the mission has been a success.

Dr Morris Jones is an Australian space analyst who has written for spacedaily.com since 1999. Email morrisjonesNOSPAMhotmail.com. Replace NOSPAM with @ to send email. Dr Jones will answer media inquiries.