Those who are particularly cynical about the justification for spaceflight budgets enjoy an amusing little circular argument. Question: why do we have the International Space Station. Answer: so the Space Shuttle has someplace to fly. Question: then, why do we have the Space Shuttle? Answer: to get to the Space Station, of course.
In these troubled financial times, such games demand more than a cursory brush-off. But, based on presentations to the second international conference on space exploration on 21 October in Brussels, it was easy to conclude that, nobody has much of an idea of what to do with the ISS.
More than 30 countries - including members of the European Space Agency, the European Union, Russia, the USA and other space players ranging from Japan to South Africa - were represented by ministers or their proxies.
Yet while speaker after speaker praised the ISS as a model of successful international collaboration in space and a magnificent orbiting laboratory, none presented a specific vision for the station, beyond the need to agree on its use to test technologies that may support journeys deeper into space.
ESA director general Jean-Jacques Dordain has no time for the cynics. Speaking to Flight International on the conference sidelines, he stressed that ESA, NASA and their international partners have suddenly been presented with a vast new opportunity with the ISS.
A year ago there was intense US space budget competition between the ISS and the return-to-the-Moon Constellation programme, but with Constellation's cancellation and US determination to support maintenance of the station up to 2020 and perhaps beyond, the game has changed.
Now, says Dordain, scientists have a 10-year or longer time horizon to plan for ISS use. That is a period longer than a PhD programme, he notes - long enough to offer exciting opportunities for science.
As the gathering in Brussels made clear, much of that ISS-based science can be directed to developing technologies that will drive exploration of the solar system, by both unmanned and manned missions.
ESA Council chairman Giuseppe Pizza struck a key theme in stressing the need to develop new propulsion and space transport technologies. Critically, he said, breakthrough technologies are needed in human life support systems, which so far cannot operate independently of supplies from Earth.
ALL TOGETHER, NOW
Pizza's opening remarks, underscored by several subsequent speakers, stressed that in the current economic climate, co-operation between spacefaring nations is more important than ever. Indeed, said Pizza, there is no question of achieving ambitious scientific objectives or opening a significant new chapter in space exploration without a global strategy, including the active participation of every European player.
Or, as NASA deputy associate administrator for exploration Laurie Leshin put it, if there is to be a human presence in deep space in a reasonable timeframe, there is no way forward but collaboration. Describing the NASA-ESA relationship as "robust and effective", she added: "Exploration begins with the ISS" and its "huge opportunities" for discovery.
Frank de Winne - Belgian air force brigadier general and the first non-US or Russian astronaut to command an ISS mission and chairman of the technical steering group advising European space ministers - placed a great deal of emphasis on forging a co-operative effort to improve life support system technologies, as well as an international agreement on a common space transport system able to provide what he calls "balanced, sensible access to space".
The Russian delegation called for a co-ordinated, international approach to developing rockets to complement its workhorse Soyuz launchers, ships for interplanetary travel and nuclear propulsion. Co-operative Moon missions should focus on mapping and then rover landings.
Clearly, while the 1960s US-Soviet space race may have made the Apollo Moon landings possible, that sort of competition is no longer a valid approach. But, as the conference also made clear, there are limits on what can be achieved through collaboration. Dordain noted that while co-operation will pay dividends in access to space, Europe needs to establish independent access capability, at least for non-exploration type missions.
De Winne himself may have foretold a thread of tension in a co-operative future by noting that Europe "should be part of exploration because we want to bring our European values to this venture". That means, he said, that the citizen must be the central focus of Europe's thinking about how to approach space exploration and bring benefits in technology to Earth.
De Winne clearly embodies a grander European vision of the future. The astronaut freely admits to having been inspired as a child by the Star Trek vision of "voyages focusing on discoveries and human values [of] universal liberty, equality, justice, diplomacy and co-operation between societies".
For now, specific plans and programmes remain elusive. The ministers meeting in Brussels merely agreed to join forces to develop technologies enabling space exploration, to seek better exploitation of the ISS and to establish a dedicated, high-level inter-government platform to co-ordinate international space exploration efforts.
Italy, in its capacity as ESA president, offered to host the first meeting of this high-level group a year from now in Lucca. It seems likely that Pizza and his colleagues will, as hosts, be looking to wrap up that gathering with some detailed plans - with a European flavour - for this new era of co-operation.