By Helen Briggs
BBC News Online
Britain's commitment to future Mars missions remains in doubt, despite the success of the Beagle 2 project.
European Mars landing 2009?
Academia and industry battled against all odds to build the probe, which is set to land on Mars on Christmas Day.
It has left British companies in prime position to win key contracts for space missions planned in the next decade.
But a shortfall in funding could leave the UK flagging behind other European countries in the race to explore the planet with new landers and orbiters.
Future European Mars exploration comes under the umbrella of the Aurora programme - the European Space Agency's (Esa) bold vision to land probes, and, eventually, astronauts on the Red Planet.
The ExoMars mission, set for 2009, would investigate the biology of the planet, paving the way for a more ambitious proposal to bring samples of Martian rock back to Earth for analysis.
The space and satellite company EADS Astrium (UK) built the Beagle 2 lander at its facilities in Stevenage, Hertfordshire.
The firm has won a pilot study to investigate the costs and technical challenges of the Mars sample return mission.
It has also put in a proposal for the ExoMars mission to design a rover capable of trundling over the dusty surface of the planet and drilling two metres underground.
Esa has selected another UK company, Surrey SatelliteTechnology Limited in Guildford, Surrey, to develop and test a small space craft capable of carrying a lump of Mars back to Earth.
However, Britain's lead in these ventures could be scuppered by the thorny issue of space science funding.
Esa contracts are awarded on a "fair return" basis - countries that put more money into the programme can expect a bigger share of the jobs.
The UK signed up to the preparatory stages of the Aurora programme two years ago, investing 1.4m euro (£0.8m).
It has yet to decide whether to join the full programme, which includes the two new Mars missions. The deadline is Esa's next ministerial meeting at the end of 2004.
There is another fly in the ointment. Esa has asked participating countries to pay an additional subscription by the end of this year to accelerate the programme. The UK has been asked to contribute an extra 8m euro (£5m).
Under current policy, the Particle Physics and Astronomy Research Council (PParc) has the task of divvying up the space science research budget.
Dave Hall is PParc representative at the British National Space Centre (BNSC), a voluntary partnership, formed from 10 government departments and research councils, to coordinate UK civil space activity.
He says the UK cannot meet the top-up fee without cutting existing space science programmes.
He says Esa, which has budget problems of its own, is being "optimistic" by asking for interim funding at this stage.
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"The UK industry has been very well positioned in those early studies," he told BBC News Online.
"To ask for 8m [euro] when our original contribution was 1.4m [euro] is a bit disappointing.
"Basically, there's no way that the UK can find 8m euro from its existing budgets this calendar year."
Hall says the UK has no intention of committing the money at this stage, when the full programme costs and goals are unclear.
"It would be putting that money at risk," says Hall.
PParc's entire budget for space science amounts to 100m euro (£60m) a year, which includes a mandatory contribution of 70m (£50m) euro to Esa's science programme.
The cost of going into the full Aurora programme would come in at around 20m euro a year (£14m), he says. This would mean blowing almost the entire UK space science research budget on Mars exploration.
However, the powers that be are caught between a rock and a hard place. If they decide to drop out of Aurora, British scientists and engineers, who fought so hard to get Beagle to Mars, could be left sitting on the sidelines.
Dr David Parker looks after future space science projects at EADS Astrium UK.
"Beagle has really brought the UK science and engineering community together in a way that has never happened before," he says. "It's captured our imaginations as well as the imaginations of the general public."
He believes UK industry must focus on the things it does well - science and robotic missions - and Aurora is perhaps the best way forward. It would be a sad day, he says, if the UK were to bow out of the programme.
"I think we'd really be disappointed," Parker told BBC News Online.
"A lot of effort has gone in from the government, from industry and from the scientists so we really ought to build on this, having created this capability. It's a good thing for Britain, I think."
Ironically, when it comes to Mars missions, the UK is now back on familiar territory.
In the early days of the Beagle project, Colin Pillinger, professor of planetary sciences at the Open University in Milton Keynes, lobbied Esa to include a lander on its 2003 Mars Express mission.
No funds were forthcoming from the UK Government at the time, because its space budget had already been allocated to other projects.
Pillinger was forced to campaign for the money to get Beagle 2 off the ground, eventually securing help and money from industry, universities and research councils.
But Dave Hall believes things are a little brighter this time round.
He says the way forward with Aurora is to persuade other government departments and research councils to put money into the pot.
It remains to be seen whether bodies like the Department of Trade and Industry and the Engineering and Physical Sciences Research Council will want to join forces.