Bad behaviour by international models keeps the entertainment media richly supplied with stories. Don't worry. This article is about something completely different. Since the Shenzhou program made its public debut in 1999, China has been releasing models of the spacecraft and the rocket that launches it. Large models have sometimes toured as exhibits for museums and space congresses.

Small models have gone on sale to the public. The models have often been useful for helping us to understand the design and functionality of China's space hardware.

This was especially true in the earliest days of Shenzhou, when hard information was scarce. Analysts would study the models for clues to the antennas, thrusters and other equipment that could be seen on the outside of the spacecraft. Getting clues to the interior was more difficult. We gained a lot from our encounters with China's space models at the turn of the millennium but we could also misinterpret what we saw. The models were not always trustworthy. Admittedly, they were never intended to be totally accurate engineering analogues, but we had little else to use.

As the Shenzhou program has advanced, we have been treated to a growing library of photographs and video of the real spacecraft. Our dependence on replicas has grown less. That's given us a far more reliable understanding of Shenzhou, and it's also more satisfying to simply look at the real thing.

But China has continued to release models of its spacecraft over the years, and like catwalk models, some of them can be considered to be naughty. Certain models have revealed features that are not present on real spacecraft. Are these accidental errors by the model makers, or do they point to otherwise hidden chapters of the Shenzhou program?

Take a well-circulated metal replica of the Shenzhou 7 spacecraft, which was used in China's first spacewalk. The spacecraft's large cylindrical "orbital module" at its front was converted to an airlock for this task. This marked a major departure from previous orbital modules, which featured solar panels, small thrusters and propellant tanks.

Previous orbital modules could fly independently as uncrewed satellites once the bell-shaped "descent module" of Shenzhou had returned to Earth. Suddenly, we had a stripped-back orbital module. This model correctly depicts the gas bottles and the small satellited carried at the front of the real Shenzhou 7 spacecraft, and also deletes the solar panels that were found on earlier vehicles. But the exterior panel containing propellant tanks for the module's thrusters is still there on this model.

There were no thruster propellant tanks on the real spacecraft, as there were no thrusters, so the model was inaccurate. It would have also been cheaper to make the model by deleting this part, but the manufacturers didn't notice. We can assume that the manufacturers started with an existing model design for earlier Shenzhou spacecraft and added the most obvious modifications, while also deleting the solar panels.

These differences could have been visible in photography of the real spacecraft. The failure to delete the propellant tanks could have been due to a lack of photography of one side of the spacecraft! In the absence of a 360-degree view of Shenzhou, what wasn't shown was assumed to be unchanged.

The lesson of the naughty Shenzhou 7 model is clear. We cannot always trust them to tell the truth. The temptation to include a gratuitous joke about certain fashion models will now be resisted.

This lesson prepares us for the most extreme cause of a naughty Chinese space model encountered by this analyst. Procured in Shanghai in 2009, this model was released long before China had given the world a close look at the real Shenzhou 8 spacecraft, which would be the first Shenzhou to feature a docking system. This small model depicts a Shenzhou vehicle with an APAS-style docking system at its front, and solar panels on the side of its orbital module.

This was a surprise to see, especially as Chinese artwork had already suggested that the docking version of Shenzhou would not include these extra solar panels. Did the model wickedly whisper of secret plans that officialdom did not want to reveal? Was there a plan at some point for a Shenzhou with a docking system and two sets of solar panels? Probably not.

This curious model is probably the result of sloppy industrial design by the manufacturer, who merely grafted a docking system onto the front of a first-generation Shenzhou model. For technical reasons, having the extra solar panels seems most unlikely. They are not really needed to power a Shenzhou in flight, and they have the potential to impede the Shenzhou's rendezvous and docking systems. Also, the orbital module is not used for an extended mission after the crew return to Earth, so an independent power system for this module is not required.

China has recently released some nice replicas of the operational Shenzhou spacecraft, which made its debut with the Shenzhou 8 mission. Replicas of the Tiangong 1 space laboratory have also been circulated by Chinese manufacturers. Apart from being nice to look at, the models seem to have a high level of technical fidelity, with the numerous sensors and instruments used in the rendezvous and docking system faithfully reproduced. China's space models are settling down and becoming more dependable. Let's hope we get some nice replicas of China's future high-profile spacecraft in the future.

Dr Morris Jones has reported on the Shenzhou program for spacedaily.com since 1999. Email morrisjonesNOSPAMhotmail.com. Replace NOSPAM with @ to send email. Dr Jones will answer media inquiries.