- 449.90 MB
HORIZON 2005 Titan - A Place Like Home
Over a billion kilometres away, Saturn's largest moon, Titan, holds tantalising clues to how
life began here on Earth
In the most ambitious and expensive interplanetary space mission of all time, the Cassini-
Huygens spacecraft made a seven-year trek across the Solar System to attempt first contact
with the Earth-like moon of Titan by landing a probe on its unseen surface.
The first close up images of Saturn and its many moons were taken in the early 1980s by the
Voyager One Deep Space Probe. One moon stood out from all the rest, the mysterious moon of
Titan. Unlike any moon that had ever been seen, it had a thick almost Earth-like atmosphere.
It was also shrouded in a thick orange haze which prevented Voyager from seeing down to the
moon's surface. Scientists knew they had to go back.
Launched in 1997, the Cassini-Huygens spacecraft was the result of a unique transatlantic
$3.2 billion collaboration between NASA and the European space agencies. Steered from NASA's
JPL mission control in Pasadena California, the craft took seven years to reach Saturn. It
took a long slingshot route via Venus twice, the Earth and Jupiter to pick up enough speed
to reach its final destination.
When it finally arrived in July 2004, the spacecraft had to carry out a very dangerous
manoeuvre and pass between Saturn's rings in order to get into orbit around the giant
planet. Even the tiniest grain of dust could have ripped through the spacecraft and
destroyed the mission.
On Christmas Day 2004, the European-built Huygens probe was finally released from the
Cassini mothership, ready to descend to Titan. The probe's trajectory had to be absolutely
spot on, as without any engines even a slight misjudgement could not be corrected later and
would mean Huygens missing its target altogether.
January 14 2005. The Huygens probe finally reached Titan's upper atmosphere. Mission control
had now transferred to ESA in Darmstardt, Germany, but all the scientists could do was sit
and wait, as the probe was running on automatic. For any chance of success, the probe's heat
shield had to protect the craft from the fierce temperatures of re-entry, and its three
parachutes had to deploy correctly in sequence to slow its descent.
Amazingly, long before they expected to hear from Huygens, the probe's faint carrier signal
was picked up on Earth by the massive Robert C Byrd radio telescope at Greenbank in West
Virginia. Not much stronger than a mobile phone, and travelling over a billion kilometres
through space, the signal was too weak to carry any real data, but at least they knew the
probe had survived entry and was now under parachute.
Some hours later, the scientific data finally started coming through, relayed via the
orbiting Cassini. To their horror, one of the vital data-streams had not been switched on.
Fortunately most of the data was coming through on the single channel, but crucially half
the images were lost.
After years of waiting, Titan was finally revealed. With Huygens built to sniff and taste
the atmosphere on its way down, it discovered it was similar in many ways to that of the
Earth in its infancy, four billion years ago. Titan's chemistry is still a long way from
what we see as 'living', yet it was found to contain a rich cocktail of organic carbon-based
chemicals, thought to be important as the precursors to life.
Now visible beneath the impenetrable orange haze, Titan appears to look a lot like Earth.
The images beamed back from over a billion kilometres away show lake beds, river channels,
gulleys and canyons. But these river channels are gouged not by water, but by a rain of
liquid methane. The surface itself is not made of rock, but of solid ice, and Huygens'
landing site was strewn with small round ice pebbles, lying in a bed of icy sand grains.
Although home to a somewhat cold alien chemistry, in many respects Titan is driven by
exactly the same geological and meteorological processes that shape and contour our own
planet. Titan is certainly a place like home.
Video Codec :Divx 5.21
Video Bitrate :1119 kb/s
Video Resolution :720x400 (1.80:1)
Video Aspect Ratio :16:9
Audio Codec :MP3
Audio BitRate :160 kb/s (80/ch, stereo) CBR 44100 Hz
Audio Channels :2
RunTime Per Part :49m
Part Size :449mb
Ripped by cotcubt (UKNova)