It's not just the Americans who have military intentions in space. Credit: © ESA

According to nursery lore, Chicken Little, having received a light knock from a falling acorn, ran around screaming hysterically that the sky was about to collapse on our heads. This histrionic broadcast of exaggerated events led her to near-apocalypse in the person of the evil Foxy Loxy.

In ""Hostile Space":http://www.nature.com/news/2004/041115/full/041115-2.html"1, my friend and colleague Philip Ball warns of the dangers of US imperialism in space. He refers to ambitions that would not only violate treaty obligations, but also pose a physical threat to the Galileo satellite cluster, which is proposed by the European Space Agency (ESA) as a rival to the US-controlled Global Positioning System (GPS).

Ball mentions a letter from the US deputy secretary of defence Paul Wolfowitz to European defence ministers "telling them in no uncertain terms how he disapproved of ESA's bid for independence". Given the tone of Ball's article, you'd be forgiven for thinking that Wolfowitz had declared war.

You'd be forgiven for thinking that Wolfowitz had declared war.

I feel compelled to present the other side of the argument, to argue against hysteria about the sky falling on our heads. It is simplistic to portray US ambitions in space as 'bad' and European projects as 'good'. Galileo has, intentionally and inescapably, a military function. And it is being bankrolled by nations, such as China, whose strategic objectives are transparently at odds with declared US strategy.

I argue that the contents of the Wolfowitz letter were fairly mundane, and perfectly reasonable in the circumstances, and that the United States and the European Union (EU) subsequently reached a satisfactory accommodation. If Galileo had proceeded as planned, the risk of the US interventions that Ball imagines might not only have been real, but justified.

Overlap spat

In 2001 it became apparent that Galileo might plan to use frequencies that would impinge on those already used by the GPS system. Wolfowitz wrote to EU defence ministers of his " concerns about security ramifications".

He explained that the US military, which governs the GPS, were planning "spectral separation of the GPS military signals from civil signals" and that the addition of any Galileo service in the same region would make it difficult to ensure the "availability of critical GPS services in time of crisis or conflict".

One can only sympathize with Wolfowitz's frustration: whereas the GPS is controlled by a small and flexible panel in the US military, the proposed administration of Galileo has all the hallmarks of EU obfuscation, inefficiency and waste.

Getting the EU to agree to a split-second frequency change in a time of crisis, such as the United States might demand in time of war, would be as frustrating as trying to nail jelly to the ceiling. Put in this light, Wolfowitz's letter shows extraordinary restraint, and certainly doesn't convey any kind of threat.

His letter sent the EU into a tailspin. But in 2004, the EU and the United States agreed to work together to resolve technical issues such as frequency use. Far from shooting Galileo out of the sky, the United States simply seems keen to ensure that Galileo does not impinge on its own system.

Free for all

But the conclusion of Ball's with which I disagree most strongly is that space is a domain of peace, which the United States alone is intent on shattering. It seems clear that the EU is playing exactly the same game. Indeed, in March 2003, the EU's Directorate-General of Energy and Transport explicitly stated that Galileo would give the Europe a military capability.

This military dimension leads one to wonder why the project is run by the seemingly innocuous transport department. It is as if the EU is trying to hide its intentions.

Writing on the website of the Bruges Group2, a right-wing Eurosceptic think-tank, Richard North notes that the most worrying aspect of the Galileo project "is the almost wilful refusal to accept publicly that there are military implications".

The EU is planning to release its Public Regulated Service signal to a large number of players, without any realistic chance of controlling access or affording the United States an easy means of blocking it, says North. This constitutes a potent weapon that could be used by enemies of EU member states, the United States and its allies.

More worrying still is the fact that non-EU states whose strategic aims are at variance with those of the United States, notably China, are bankrolling Galileo. "It can only be self-deception on a colossal scale if the EU believes that China will not employ Galileo for military purposes," writes North, who goes on to depict a worrying scenario.

"Since the US is a committed ally of Taiwan, and has guaranteed the security and independence of the island," writes North, "in a conflict situation the US could find itself at the receiving end of weapons or systems which utilize Galileo signals." And it might find itself compelled to take "direct action".

This scenario is at least as worrying as any painted by Ball. In contrast to the nightmares of Chicken Little, it could be this kind of geopolitical nightmare that Mr Wolfowitz was keen, not to promote, but to avoid.