Support science's risk-takers, urges John Zarnecki, as he waits for explosive news from Titan
On Friday afternoon, a 300kg flying saucer moving at 22,000kph will begin its descent towards the surface of Titan.
After a journey of 3.5 billion km on the Cassini spacecraft, the Huygens probe, one of the most sophisticated autonomous robots ever built, will slow itself through friction and then glide on a sequence of parachutes.
It will fall for more than two hours, analysing the atmosphere of Saturn's giant moon before touching down to gather data that could help us understand how life first developed in the solar system.
The landing is incredibly risky. We do not even know if the surface of Titan is solid, covered in seas of liquefied petroleum gas or cloaked in organic gunge. Huygens might hit a sharp rock or topple into a crevasse.
All in all, Huygens has a reasonable chance of survival.
The UK's involvement in the project is mostly concentrated in my experiment, the "surface science package". Its aim is to characterise the landing site. But it will also record the composition of Titan's atmosphere during the descent, registering the buffeting of its winds and the presence of heavy organic rain clouds.
It will then analyse the nature of whatever Huygens lands on, perhaps measuring waves on a sea or probing the electrical properties of an icy plain. We hope that any data we get from the surface will be beyond our wildest dreams.
Titan might present us with our best bet for understanding the origins of life. The Earth has changed so much since the first long-chain hydrocarbons formed, eventually leading to nucleic acids and very primitive life.
Titan, with its coating of organic molecules, could provide an astrobiological link to that lost environment.
But to find out we have to push ourselves. And when you do this, you have to bear the occasional failure - Huygens is a high-risk mission. How might the public view such a failure, should it happen, so soon after Beagle 2 ? They might think "these guys are hopeless - let's leave space to the Americans and Russians".
UK space science never has enough money but we have a good standing in the world scientific community.
If Huygens were to fail, the fear is that the politicians might decide to switch future funding to more medical research, for example.
I am not arguing for failure, but you have got to be allowed to take risks.
When Europeans first went to the distant corners of the earth, ships sank.
That was costly at the time, but they persevered.
I would liken this sort of planetary mission to those pioneering voyages of discovery.
The only way to avoid failure is not to take any risks and that's the way not to make progress. The question is, in our risk-averse society, what degree of risk can we tolerate?
As scientists we are now constantly assessed. I have worked on Huygens since the beginning, 14 years ago, and so far I have not collected a single piece of scientific data.
If we get all we hope for in just four hours on Friday afternoon, my colleagues and I should produce a flood of top-quality papers over the next five years and maybe rewrite the textbooks on the origins of life.
But if we get nothing, what happens come the next research assessment exercise? No papers, no boxes ticked - like the public, the assessors would view the whole thing as a failure and perhaps decide that I do not deserve any support in future.
And if we adopt that philosophy, only support science that's "safe" and produces two solid papers a year rather than support people who take risks, we will never rattle the cage.
My involvement in Beagle 2 was limited to one small instrument. But when it failed to make contact from the surface of Mars, I had the worst Christmas of my life. It was grim.
Beagle 2 could have worked. The dividing line between success and failure can be very small.
Now I wait at the European Space Operations Centre in Darmstadt, Germany, to hear from Huygens .
John Zarnecki is professor of space science at the Open University and principal investigator on Huygens' surface science package. The probe is due to touch down at 2.15pm on Friday.