Here was a spaceprobe, built almost entirely in and paid for by Europe, about to meet a world in our solar system that had never been visited before, a daring mission with enormous promise - and the possibility of failure at every turn.

The arrival of Huygens at Saturn's moon Titan on January 14, after a journey of 7-12; years as a backpack of NASA's Cassini spacecraft but all on its own for the last three weeks, was one of those rare events in space history when it's all down to a few hours, minutes perhaps.

Not like those orbiters which deliver gigabytes of data over many months, not even like a flyby at a safe distance from a planet or a moon: While rich in scientific data and often spectacular imagery, there is no singular moment of truth in these achievements.

The climax of Huygens' mission promised have several of these, however, and there would be basically three ways to experience this exceedingly rare event: on the web, where numerous professional and amateur logs were being updated all the time, on a TV channel operated by the European Space Agency and also carried by NASA TV - and at the European Space Operations Centre (ESOC) in Darmstadt, Germany.

It has been pointed out on this site by Jeffrey Bell and Simon Mansfield, that the TV experience ESA provided on January 14 and 15 fell short of what these space afficionados had hoped for, though I've also seen reports from public events arranged around the same ESA TV feed in Europe and even the U.S. where visitors were happily satisfield.

I cannot comment on the overall quality and content of ESA TV's handling of the Huygens event, though, because when you chose path three of the above, coming to where the real action was, only excerpts of that program could be followed: At ESOC you were served a very different meal.

I mean this somewhat literally, by the way: The free food served around the clock to the 500 or so journalists and guests who had converged here, was excellent. It has always been ESA's way on occasions like this to mix news conferences and celebrations into one big public event: Usually this works quite well, because the typical reason for an invitation to ESOC is a launch party for a science satellite or space probe.

You hear some scientists talk about their expectations, you watch the launch (or its postponement) live on a big screen, some speeches by officials are given, and sometimes even a little cultural show is thrown in - when Envisat was launched, a jazz band played, and on the occasion of the launch of SMART-1 Wallace & Gromit's "A Great Day Out" was shown.

And then (or rather already) the buffet is open and the party is on. It was on the occasion of the orbit insertion of Mars Express on christmas morning 2003 that the proceedings had differed markedly from this plot for the first time.

While again there were no breaking scientific news that day - the orbiter's instruments would be turned on only weeks later, and Beagle 2 never phoned home - during the long event enormous access for journalists was granted to the flight engineers who did the job and reported on virtually every step.

A great day for Europe in space went by in style. Only days later, of course, the space world's focus turned away from Europe and to the Jet Propulsion Lab in the United States where the landings of the two Mars Exploration Rovers (MER) were executed in perfection - not only by the engineers and scientists who made them happen but also by those responsible for public outreach.

The key moments of both missions, from entry, descent & landing to the relaying of the first bursts of navcam pictures through orbiters a few hours later could be followed live on TV around the world, on unedited feeds directly from the JPL control rooms.

The sheer emotion an unmanned mission to another world could excite was transferred into countless living rooms, and over the following days the early scientific outcome was presented in a string of equally gripping news conferences.

And now, exactly one year later, it was Europe's turn again, with the entry of a robotic envoy into a world even less known than Mars, where no spacecraft had ever descended before. Would ESA follow the striking example NASA had set with the MER?

Would the world be able to watch in real-time how things unfolded during the critical minutes, and would everyone be allowed to share the excitement and joy - or disappointment - of the scientists, especially those running the cameras (DISR) on Huygens, when they got their first real data on their computer screens?

There had been much debate inside ESA, and between ESA and the Huygens scientists as well as with the media, the latter eager for a MER-like made-for-TV event. The constraints were much tougher than with the MER (or Mars Pathfinder in 1997), of course: Huygens would transmit all its housekeeping and science data only to the Cassini orbiter which would relay them to Earth no less than 6 hours after everything happened. Not exactly a 'live event', you say? But wait!

Regarding entry, descent and landing, there would be a network of huge radio telescopes trying to intercept Huygens' transmission, so a simple life sign could be hoped for almost in real-time. And the arrival especially of the pictures would be in a burst very similar to the MER experience: They would suddenly be there, all at once and at a known time, some eight hours later.

There were considerable fears among ESA and the DISR scientists alike that those raw images would show next to nothing: They would have low contrast because of Titan's ubiquitous haze, one was told, they would have small fields of view (because they were meant to be combined into large panoramas) and whatever was on them would probably make no sense to anybody.

The plan thus was that the DISR team would have everything for themselves, for however long it would take them to assemble something intelligible out of the raw data. If already the raw images were shown to the world, the argument also went, there would have to be DISR scientists around to explain them - who would then be unable to improve them for later showing!

The original plan called for the release of a few first improved DISR pictures perhaps near midnight CET, which would be about 4 hours after their availibility to the scientists - the press was expected to just wait it out.

Partly due to the pressure from many media representatives, I've been told, the plans were changed shortly before January 14, to the release of some raw DISR images with a shorter delay, but there was still no intention of having their actual arrival staged in a MER-like manner.

The risk in such a brutal openness is clear: What if the MER navcams or the data transmissions had failed? A live broadcast of the downlinking of the first-ever image from the camera of Mars Express - which was never considered anyway - would have been a disaster, for example: It was completely white, due to severe overexposure because of too much dust in the Martian atmosphere in January 2004 (with better exposure settings the picture coming in the next day was then near-perfect). Taking a MER-style risk would have paid off tremendously for the DISR images, however, more than most could have imagined.

Here's then how things did play out on January 14th, 2005, at ESOC during a 15-hour event that was at first choreographed in every detail and would eventually become totally improvised. All times given in the following narrative are in Central European Time (CET) = UTC + 1 hour, and all events at Titan are reported 67 to 68 minutes later (Earth-receive Time), i.e. when a radio signal reporting them could have reached Earth, even if none was actually sent.

On normal days the European Space Operations Centre looks little other than an office block or a large scientific institute: You meet a lot of managers, engineers and scientists, and some of them are actually controlling Europe's precious spacecraft, about a dozen at a time, from banks of computers. During special activities, the somber atmosphere changes, however, especially when the media are invited, and now the campus was busy as hardly ever before, with tons of cables, TV satellite trucks and even an open-air stage built by the BBC - a rather strange approach, given the sub- freezing temperatures, especially since they would have more on- air interviews than anybody else.

The science event/festivities commenced at 10:00 CET, with nothing to report about the state of Huygens, of course: The little spaceprobe would be silent from the moment it had left its Cassini carrier last December 25 until it had survived the fiery entry into Titan's upper atmosphere. At 6:49 CET it should have woken up, at 11:13 it was to hit atmosphere (the 'interface' in mission control lingo), and at 11:18 the main parachute should be open, the heat shield gone and the transmitter on.

It was some time between 11:20 and 11:25 CET that the radio astronomers were sure that one of their big dishes, the Green Bank Telescope in West Virginia, had detected the carrier wave from Huygens, but it took was already 11:39 when the anchor of the stage show in the densely packed ESOC auditorium broke the news.

For reasons beyond my understanding, ESA - though admittedly very short in cash for outreach activities - chose to run its own coverage of events on ESA TV and the event in the auditorium independently, and it may actually have been that ESA TV had these particular good news a few minutes before the gathered crowd.

In any case the message was now clear (and explained well by various mission engineers in the following minutes): Many critical milestones of the atmospheric entry and descent must had been passed already for the carrier to appear, and everything up to the deployment of the main parachute had obviously worked!

There was little else that could be gleaned from the exceedingly weak carrier at that point, and it could not even be said where there were any data modulated on the wave. But its sheer existence was reason enough for optimism.

At 13:30 a formal news conference, the science directors of ESA and NASA, side by side, hailed a major engineering success which was beyond doubt at that point: Green Bank had seen a solid signal for almost two hours, until Titan had set for that location at 13:10 CET - and the news had just come in that �the Dish� at Parkes in Australia, famous from its role in the Apollo 11 mission and known from a much- acclaimed Australian docu-comedy, had reaquired Huygens, another announcement causing cheers from the crowd.

After the short news conference wound up, some key scientists and engineers made themselves available to the media. Leonid Gurvits who had organized the worldwide network of radio telescopes was happy to give away as much technical detail as you could want.

He told me how only in the last few years radioastronomical techniques had become advanced enough to even try to intercept Huygens' transmissions to Cassini and that nothing like that had been in the plans when the mission was launched.

Despite many obstacles, e.g. the unfamiliar transmission frequencies, the exceedingly weak signal strength (like an ordinary mobile phone on Saturn) and the lack of suitable cosmic radio sources in the vicinity of Titan, Gurvits was already optimistic that the radio telescopes, working in interferometric fashion, would be able to pin down Huygens' position to about 1 kilometer in space.

There were also indications in the Green Bank data for severe wind gusts in the upper atmosphere but none of that closer to the surface. Huygens seemed to have a smooth ride down.

Little of that exciting information reached the outside world, though, as the media operations had been all but suspended for three hours. It was actually from an ESOC scientist - as well as one of the international web logs I read on his office computer - that I learned about the longevity of Huygens which must have reached the surface long ago (at 13:45 CET, it was later announced): Parkes still heard a strong signal while the landing site was about to disappear below Cassini's horizon. Things got tense again after just 17:00 CET when the data stream hopefully intercepted by the orbiter was about to be downlinked to Earth.

The stage in the ESOC auditorium was empty, but on a big projection screen you could now follow events at the main mission control room: Not only the key engineers had assembled there but also some dignitaries, including the German minister for science. There was no running commentary, and there was no reaction visible from the people in the control room either when the 17:15 mark passed: That was the moment when the first Huygens bits were expected.

Minutes passed by in which we could only watch the tense faces of those on the screen - and finally, at 17:19, their sudden cheering was echoed in the auditorium. Eleven minutes later the top management, including the minister, came triumphantly marching into the packed auditorium where the PR staff had to fight hard to keep the scores of TV people at distance.

First the Director General of ESA declared �science success� as there really were data from Huygens in the downlink, then the mission chief first broke the news that is was only one of the two channels on which there were good data. And the information was confirmed that Huygens had continued transmitting for over two hours from Titan's surface, until Parkes could not follow it anymore at 16:55 CET.

Radio astronomers in Europe were now frantically trying to catch more of the carrier, but as there were no live links to them - who would have thought that they'd be in the game at all - there would be no information for some time how long Huygens really survived.

In explaining the status of Huygens in more detail, how all entry milestones had taken place within 15 seconds of the plan, that the temperature inside the capsule had been a balmy +25°C at first, and that not a single data package on the working channel B was lost, a key manager then made a crucial mistake.

He explicitly talked of full redundancy in Huygens' data channels and even called it a 'double probe' - and only later admitted that one of the Huygens experiments (that was to get wind speeds from the Doppler shift in the frequency of channel A) was not redundant at all and now a total loss.

It was actually through rumors from several space scientists not involved in the mission at all that one could learn in the following hours that someone had forgotten to turn on the receiver for channel A onboard Cassini! What had been told to the media at first had sounded more like some problem with the data on a - working - channel A that might even be recoverable if need be. And asking for details brought no clearer response.

Why the crucial command to the Cassini receiver was missing is now being investigated formally by ESA - it was obviously a human mistake that should have been caught at some point, according to the prescribed ground procedures but wasn't. And it had consequences beyond the loss of the Doppler Wind Experiment (the information from which can be reconstructed in full from the carrier tracking with the radio telescopes).

It was only when I finally had chance to meet the principal investigator of the DISR cameras, Marty Tomasko, after 19:00, that I learned in detail about the other non-redundancy in the data transmission: Half of all the images would be lost, because they had been sent alternately on channels A and B. The huge amount of data, compared to the other instruments, had made that necessary, and now the hoped-for panoramas would have ugly gaps which he intended to fill up with interpolated images, though.

Tomasko also disclosed how bad things had really looked between 17:15 and 17:19 when they had waited in vain for the first bit from Huygens: Many had thought it possible then that nothing whatsoever had been transmitted to Cassini (and he had already pondered booking the next plane home to Arizona).

But now he knew that the DISR cameras had worked well, that the downlink from Cassini was about complete and that now the data from the various instruments could be extracted shortly and sent to the various experiment teams - some had been working on Cassini for 25 years.

The teams had set up their computers in so-called portacabins, shacks like those used on construction sites, and it was in front of the DISR cabin where I had talked with Tomasko. He had actually invited me earlier to be present when their first pictures came in, and this was right now! At least from outside the small cabin's windows I could witness the historic moment that will never repeat and that the world was not to share - and what a moment it was!

The raw images flooding the computer screens all at once at 19:27 CET were just amazing, in particular a view directly from the ground that repeated again and again (as the camera was fixed and the capsule was not moving anymore after making ground contact). And many the completely unprocessed raw images were of stunning contrast and sharpness: The scene absolutely equalled the arrival of the MER images, especially from Opportunity, as did the excited reactions of the overwhelmed DISR scientists.

But there was no live feed of all of that to the eagerly waiting world and not even a pool TV reporter or one of ESA's own cameras around: Missing this opportunity is, not only in my opinion, a public relations blunder beyond belief. Even if you didn't have the confidence that the raw images would be good enough for live TV, you could at least have put a camera of your own in the room - just as NASA did when the Hubble images of the impact of the first fragment of comet Shoemaker-Levy 9 into Jupiter appeared on the computer screens at the Space Telescope Science Institute.

The video clip of the reactions of the Hubble scientists, from the sheer joy of some to the stunned disbelief of others, had immediately become the key visual moment to illustrate the whole celestial drama for the world - and there is no such imagery for Huygens' triumph when there could be. So how would the world eventually learn that Huygens and DISR had worked so wonderfully?

An announcement had been made already in the afternoon that at 20:30 or 20:45 one raw image would be shown on screens everywhere, though without further commentary, about the only concession to the picture-eager crowd planned at that time.

It was actually 20:56 CET when exactly one Huygens picture did appear as promised - and to the utter disbelief of those (very few) who already knew about the breathtaking view from the ground, it was a view from 16 kilometers up. Amazing, no doubt, and much sharper than any of the images from Cassini's own camera, with indications of drainange channels and something like a lake's shore. But for the public at large vastly less impressive than the one ground view, of course.

The presentation of the lonely 16 km view had been embedded in a short show on ESA TV that had been staged in the main control room (which had nothing to do with the images themselves that were all handled in the portacabin) and that had such a strange script that to many - among the journalists at ESOC as well as those following the feed around the world - it felt almost like a parody.

At first only people watching an invisible screen were shown, probably a mistake by the director, then the image came up, with Tomasko giving a brief explanation. Then, instead of showing more (which were in the system - one of them accidentally flashed on the screen for a fraction of a second), numerous dignitaries gave congratulatory speeches in their native languages. And then it was over!

The press, including still many of the TV crews, had been waiting in ESOC's cafeteria for several hours, and now we were looking at each other with bland faces: What, that was it? The greatest moment of one of ESA's greatest achievements wasted? And why on Earth were they withholding the incredible view from Titan's surface from the world?

Fortunately things turned for the better after just a few minutes: Into the cafeteria marched Tomasko himself and John Zarnecki from the Surface Science Package, to applause from the press crowd just working the dessert.

And here it was, in a totally improvised news conference in the ESOC cafeteria, which was also not carried on ESA's or - to my knowledge - any other live TV, that the first scientific sensations of the Huygens mission were finally revealed to us! Tomasko had three images to show by now, the one from 16 km, another - even more confusing - aerial shot from lower down, and then the ground view.

It was 21:18 CET when the latter was finally revealed to the applauding reporters at ESOC, and some minutes later, I understand, it appeared unceremoneously on ESA's website. Not only was the moment of its actual arrival on the DISR computers nearly 2 hours earlier lost for the world, but also its public presentation - which would have offered another chance to pull equal to NASA's recent triumphs - took place without the world being able to watch.

Fortunately some TV crews were alert enough to catch these moments for the late-night newscasts - the delay of the image release had meant, however, that all primetime shows had missed them. In any case, the impromptu cafeteria news conference was clearly the scientific highlight of the day (as a short ESA TV program at 23:00 CET was merely a rehash of what was said here). For the pictures alone could tell only part of Titan's story, and the Surface Science Package would add a lot more.

Zarnecki could already report that he had 3 hours and 37 minutes of continuous data, including 1 hour and 10 minutes form the surface, that the impact on a solid - but not rock-hard - surface had been measured in great detail by two sensors and that there was no evidence for any liquid right now on the place where Huygens had come down.

With that the media activities for January 14 wrapped up, while in the bitter cold outside you could catch an amazingly clear view of Saturn and many of its moons through large telescopes local amateur astronomers had put up.

The air was unusually steady for an urban site in Germany, and a wealth of detail unveiled itself to the eye. We all felt, looking at Saturn, Titan and its sister worlds, that those, somehow, were not the remote worlds of yesterday anymore.

We had touched one of them. On the next morning, Saturday January 15, many newspapers reported big, often on the front page, about the general success of the mission that had been evident even at their deadlines, but would they also take notice of the scientific findings that were now coming out? A major news conference with all principal investigators that had to say something was long planned for 11:00 CET - and once again, the ESOC auditorium was filled to and beyond capacity.

Even many of the TV crews were still there, to my amazement (as they normally tend to run away from ESOC events at their first chance) - and the presentation of the new insights into Titan's nature that had been extracted from the data over night was fully up to the standard set by NASA during the early MER days.

As everyone of the press had seen the key DISR images already last night (and the local paper even ran the now-famous ground view on the front page, above the fold), it was a clever idea to keep the best stuff for the end of the news conference and start with the drier but equally important numbers.

Gurvits declared that �100 percent� of the lost wind data would be reconstructed from the terabytes of radio telescope data. Zarecki now knew that the ground had a thin crust and that its mechanical properties resembled wet sand or clay on Earth.

Marcello Fulchignoni showed temperature and pressure profiles of the whole atmosphere and played noisy sounds reconstructed from measurements a little microphone had taken (as well as a weird sonification of radar echoes). Data from another instrument showed evidence of methane sources in the soil (that were disturbed when Huygens hit with 4.5 m/s) and for a dense cloud or haze at 18 to 20 km altitude.

The latter finding matches well with DISR's experience, about which Tomasko reported next - hed hadn't slept for 30 hours, in order to be able to meet the press again this morning! 25 km up the view to the ground was still fuzzy, but below 20 km the vision was near-perfect.

The first 360°-panorama had already been created, showing more amazing landscapes - with possible runoff channels of a liquid - in a slant view, as if looking out of a commercial airplane. And the first Near-IR spectra of the ground were available, revealing water ice with admixtures. The ground view was reminding Tomasko of icy rocks lying on a semi-wet surface where a liquid may be present on other days.

Even though one panel member had briefly fallen asleep during the news conference due to acute sleep deprivation and the mix of European accents was amazing, the response was excellent: The next Monday, January 17th, Titan was again front page news in many European papers, with especially the big panorama appearing as the lead item several times, while commentaries hailed Europe's grand achievement. And so, after all the brilliance and blunders of three days earlier, ESA's outreach effort had paid off after all.

Daniel Fischer is a space science writer based in Germany, longing for more Voyager-, Pathfinder- and MER-style live experiences in space exploration and looking forward to what NASA will make out of the Deep Impact mission

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