Relations between China and the USA have never been easy. In recent years, they have taken on an exceptionally frosty character over matters such as economic policy and strategic problems. It was against this backdrop that NASA administrator Charles Bolden made a controversial visit to China in 2010, with a view to strengthening ties between the two nations in space.

To an outside observer, Bolden's visit seemed to produce few results, apart from angering some US lawmakers. The full circumstances of Bolden's trip haven't been fully disclosed in public, so it's difficult to make judgments about it. But a matter as complex as US-China relations in space cannot be altered with speed or ease.

This author commented shortly after Bolden's trip that this seemed to be a basic handshaking tour, with a view to achieving more substantial results in future negotiations.

For better or worse, the fallout over the Bolden trip, and continuing suspicions between the USA and China, seemed to bode ill for any further progress.

This author did not expect the subject of spaceflight to be discussed in any depth during the recent tour of Chinese President Hu Jintao to the USA. Clearly, spaceflight wasn't at the top of the agenda, but it's interesting to see the issue mentioned in a joint US- Chinese statement released by the White House.

Paragraph 10 of the joint statement is as follows: "The United States and China agreed to take specific actions to deepen dialogue and exchanges in the field of space. The United States invited a Chinese delegation to visit NASA headquarters and other appropriate NASA facilities in 2011 to reciprocate for the productive visit of the U.S. NASA Administrator to China in 2010.

The two sides agreed to continue discussions on opportunities for practical future cooperation in the space arena, based on principles of transparency, reciprocity, and mutual benefit."

The statement is non-committal, and leaves plenty of room for exit strategies by either nation. It contains absolutely no references to specific projects or programs. But let's look at the donut instead of the hole. This statement suggests that there's still the potential for productive co-operation between these two major space powers. It also suggests a maturity in attitudes is unfolding, which by itself is highly desirable.

The rise of China's military power, coupled with its rising geopolitical influence, has generated much suspicion over its rapidly developing space program. Much of this is well-founded. China is using space effectively for military purposes, and this will challenge American strategic power.

China also remains generally opaque about its plans and activities. The issue of "transparency" in the joint statement is far more significant than a passing glance would suggest.

Dropping the guard and accepting Chinese assurances at face value would be naive. Caution must be practiced, but some of the statements from American lobbyists, think tanks and lawmakers borders on the histrionic. This raises tensions between the nations even further, and also serves to discredit some of the less vocal but more objective voices who properly grasp China's strategic developments. Opening

the door for further visits and dialogue is a countermeasure to some of the more extreme viewpoints on both sides.

Put simply, China and the USA could be moving closer to smiling in space. There should be a pragmatic, realistic understanding of each other's spaceflight capabilities and strategic power in space. Tensions will remain on many fronts, but they should be accepted and factored into overall planning strategies for co-operation.

The China-USA relationship is the most conspicuous "missing link" in an increasingly international space scene. For all its recent stumbling, the USA remains the world's most advanced power in space. China, in turn, is already one of the world's top space powers, and is rising rapidly.

Co-operation will only go so far, but it should take place on some fronts. Both nations have a lot to gain from it. Ventures that risk technology transfer or national security should be treated with extreme caution. Sending astronauts from both nations to shake hands in space is also unlikely to produce geopolitical changes on Earth.

Similarly, engaging in joint projects doesn't always reduce the cost or complexity of a mission. But there are plenty of other ventures that promise gains for both nations. Sharing scientific data from lunar and planetary missions is one obvious way.

This will all take a long time, and we could see only a modest amount of co-operation even in the long term. But it has to happen. The two nations cannot ignore each other. Even if this just slightly cools down some of the high tensions that dominate US-China relations at the present, it will be worth it.

Dr Morris Jones is an Australian space analyst and writer. Email morrisjonesNOSPAMhotmail.com. Replace NOSPAM with @ to send email.