Something had woken me up in the middle of the night. It could have been the glow from the skylight above my bed revealing a cloudless sky. After getting a drink of water, I gazed up from the kitchen window. Indeed, the heavens were resplendant.
Practically overhead, I recognised one very bright body, without doubt Saturn. A quick check on my sky chart confirm that it was the ringed planet. I took out my binoculars and could just about make out its distinctive shine.
Just two weeks had passed since that historic day. After living one of the most intense events ever experienced in my professional career, coming back down to Earth had been difficult. The scientists today have their months ahead cut out analysing the data. My assignment now over, I have a big void to fill.
At one in the morning, no, I was not sleep walking. But it was as though Saturn that night had beckoned me from my slumbers. I just looked at the planet, imagining its largest moon. I was some what mesmerised, just one thought in mind : “We have gone there!”
The world’s media have amply reflected the achievement. On January 14, after a seven-year journey on NASA’s Cassini Saturn-orbiter, Europe’s probe to Titan fulfilled and even surpassed the engineers’ and scientists’ greatest expectations Arriving safely on the most distant object ever visited by mankind, the Huygens mission has today thrown wide-open a window on another world.
A long day of suspense
14 January 2005… at the European Space Agency’s Mission Control Centre in Darmstadt, Germany. The world’s press and media – a record, over 700 people – have assembled to follow the probe’s descent with baited breath.
The first person to be interviewed on ESA Television’s coverage is Huygens Mission Operations Manager, Claudio Sollazzo. “Today’s the great day, and tonight I think I will really climb the walls with my bare hands.”
It will be a long day of intense suspense. Everyone knows that despite infinite precautions, success is not guaranteed, starting with the probe’s fiery entry into Titan’s atmosphere.
Gerard Huttin, Huygens project manager at the prime constructor Alcatel Space, reminds us of the inferno the probe will have to live through. “The nose of the heat shield will rise to 2000 degrees and the probe will have to withstand 15-G forces during deceleration, so this atmospheric entry is quite a challenge.”
It is 10:13 GMT… Within three minutes Huygens is dramatically slowed from 21,000 to 1400 km/hr, sufficiently for the first pilot parachute to be deployed, then quickly opening the main 8-meter canopy under which the probe will drift down for the most part of two-and-a-half hours.
In the Main Control Room, there is little to do except follow the nominal timeline. Huygens is a rare occasion of a space mission with no real-time data arriving from the spacecraft. However, a bonus radio tracking experiment, planified only within the last year, will allow us all to live this descent as though we were sitting inside the probe.
A faint beep which means so much
It is just past 10:26 GMT. We are still interviewing Gerard Huttin when from an adjacent room we suddenly hear wild screams of joy. Someone has a direct talky-walky link to the Main Control Room. At first startled, we immediately realise the significance. The cries are heart-rending exhaltations of relief.
The 110-meter Green Bank Observatory in West Virginia has in effect provided the first relief. It is one of several radio telescopes around the world to clearly hear the probe’s signal. Huygens has survived the entry. The probe is alive! The bead of a tear wells up in Gerard Huttin eyes.
At that moment the previously agreed protocole, to only announce this detection after its full confirmation at around 10:40, goes out the window. We are obliged to jump the gun and very cautiously announce that ‘apparently’ the probe has passed the first major hurdle.
A few minutes later, the chief radio scientist and JIVE astronomer Leonid Gurvits and Huygens Mission Manager and Project scientist Jean-Pierre Lebreton are standing by for first reactions.
“The telescope has received the carrier signal from Huygens. It’s about the same as a mobile telephone in our pocket but at a distance of 1.2 billion kilometres. Achieving this detection is much, much more challenging than finding a needle in a haystack,” says Gurvits.
“It looks like we heard the baby crying but we still cann’t understand what it’s telling us,” beams Lebreton. “But clearly it means the probe is alive, that the entry has been successful, we are under the parachute and the probe is transmitting.”
12:35 GMT… After having measured – we suppose but are not sure – countless characteristics of Titan’s atmosphere and taken pictures during the descent, the probe must, by then, have reached the surface. But only the recorders on the Cassini orbiter have that confirmation.
At midday in the crowded ESOC conference hall for the first mission status briefing, ESA’s Director General can however already announce the first good news. “We have a signal, meaning that we know that Huygens is alive, so that the dream IS alive,” says Jean-Jacques Dordain. “This is certainly an engineering success, and we shall see later during the afternoon if this is a scientific success.”
“I’m afraid it’s going to be a long day, we have still a long way to go,” says David Southwood, ESA’s Director of Science. “But as far as I am concerned, the baby is out of the womb, but we have yet to count the fingers and toes.”
The day will continue this way, in installments, with a series of resounding events. As Charles Elachi, JPL Director, had said at a previous press conference, discovering the true nature of Titan is like reading a mystery who-dunnit novel. Each chapter provides clues to the final answer.
Updated/maj. 31-01-2005
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