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Huygens mission science
After entering orbit around Saturn, the Cassini spacecraft will launch the European Huygens probe to make a parachute landing on the surface of the moon Titan. The scientific objectives of Huygens are explained by probe project manager Jean-Pierre Lebreton. (3min 14sec file)
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Saturn's moon Titan
Learn more about Saturn's moon Titan, which is believed to harbor a vast ocean, in this narrated movie. (4min 01sec file)
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Relive Cassini's launch
An Air Force Titan 4B rocket launches NASA's Cassini spacecraft at 4:43 a.m. October 15, 1997 from Cape Canaveral, Florida. (5min 15sec file)
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Deep Impact overview
Rick Grammier, NASA's Deep Impact project manager from the Jet Propulsion Laboratory, provides a detailed overview of the spacecraft and its mission. (4min 54sec file)
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Science preview
Deep Impact principal investigator Michael A'Hearn explains how the comet collision will occur and what scientists hope to learn. (7min 11sec file)
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Pre-flight news briefing
The pre-flight news conference is held at NASA Headquarters on December 14 to preview the Deep Impact mission to intercept a comet and blast a projectile into it. (54min 19sec file)
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Mars rover update
Steve Squyres of Cornell University, the rovers' principal investigator, discusses the latest discoveries from Spirit and Opportunity.
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Huygens descent probe landed in Titanian mud
EUROPEAN SPACE AGENCY NEWS RELEASE
Posted: January 18, 2005

Although Huygens landed on Titan's surface last Friday, activity at ESA's European Space Operations Centre (ESOC) in Darmstadt, Germany, continues at a furious pace. Scientists are still working to refine the exact location of the probe's landing site.

 
A view of Huygens probable landing site based on initial, best-guess estimates. Scientists on the Huygens Descent Imager/Spectral Radiometer (DISR) science team are still working to refine the exact location of the probe's landing site, but they estimate that it lies within the white circle shown in this image. Credits: ESA/NASA/JPL/University of Arizona
 
While Huygens rests frozen at -180 degrees Celsius on Titan's landscape, a symbolic finale to the engineering and flight phase of this historic mission, scientists have taken little time off to eat or sleep.

They have been processing, examining and analysing data, and sometimes even dreaming about it when they sleep. There's enough data to keep Huygens scientists busy for months and even years to come.

Recreating Huygens' descent profile
One of the most interesting early results is the descent profile. Some 30 scientists in the Descent Trajectory Working Group are working to recreate the trajectory of the probe as it parachuted down to Titan's surface.

The descent profile provides the important link between measurements made by instruments on the Huygens probe and the Cassini orbiter. It is also needed to understand where the probe landed on Titan. Having a profile of a probe entering an atmosphere on a Solar System body is important for future space missions.

After Huygens' main parachute unfurled in the upper atmosphere, the probe slowed to a little over 50 metres per second, or about the speed you might drive on a motorway.

In the lower atmosphere, the probe decelerated to approximately 5.4 metres per second, and drifted sideways at about 1.5 metres per second, a leisurely walking pace.

"The ride was bumpier than we thought it would be," said Martin Tomasko, Principal Investigator for the Descent Imager/Spectral Radiometer (DISR), the instrument that provided Huygens' stunning images among other data.

The probe rocked more than expected in the upper atmosphere. During its descent through high-altitude haze, it tilted at least 10 to 20 degrees. Below the haze layer, the probe was more stable, tilting less than 3 degrees.

Tomasko and others are still investigating the reason for the bumpy ride and are focusing on a suspected change in wind profile at about 25 kilometres altitude.

The bumpy ride was not the only surprise during the descent.

Landing with a splat
Scientists had theorised that the probe would drop out of the haze at between 70 and 50 kilometres. In fact, Huygens began to emerge from the haze only at 30 kilometres above the surface.

When the probe landed, it was not with a thud, or a splash, but a 'splat'. It landed in Titanian 'mud'.

"I think the biggest surprise is that we survived landing and that we lasted so long," said DISR team member Charles See. "There wasn't even a glitch at impact. That landing was a lot friendlier than we anticipated."

DISR's downward-looking High Resolution Imager camera lens apparently accumulated some material, which suggests the probe may have settled into the surface. "Either that, or we steamed hydrocarbons off the surface and they collected onto the lens," said See.

"The probe's parachute disappeared from sight on landing, so the probe probably isn't pointing east, or we would have seen the parachute," said DISR team member Mike Bushroe.

When the mission was designed, it was decided that the DISR's 20-Watt landing lamp should turn on 700 metres above the surface and illuminate the landing site for as long as 15 minutes after touchdown.

"In fact, not only did the landing lamp turn on at exactly 700 metres, but also it was still shining more than an hour later, when Cassini moved beyond Titan's horizon for its ongoing exploratory tour of the giant moon and the Saturnian system," said Tomasko.

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VIDEO: NEW PICTURES PRESENTED WITH EXPERT NARRATION QT
VIDEO: LISTEN TO SOUNDS FROM HUYGENS WITH NARRATION QT
AUDIO: LISTEN TO SOUNDS FROM HUYGENS WITH NARRATION FOR IPOD
VIDEO: RESULTS FROM HUYGENS' SURFACE SCIENCE PACKAGE QT
VIDEO: CHIEF SCIENTIST EXPLAINS COMMUNICATIONS ERROR QT
VIDEO: SATURDAY PHOTO & SCIENCE BRIEFING DIAL-UP | BROADBAND
AUDIO: SATURDAY PHOTO & SCIENCE BRIEFING FOR IPOD

VIDEO: THE FIRST PICTURE FROM HUYGENS IS REVEALED QT
VIDEO: HUYGENS POST-LANDING NEWS BRIEFING DIAL-UP
VIDEO: STATUS REPORT DURING DESCENT DIAL-UP | BROADBAND
AUDIO: MISSION STATUS REPORT DURING DESCENT FOR IPOD
VIDEO: HUYGENS PRE-ARRIVAL NEWS BRIEFING DIAL-UP | BROADBAND
AUDIO: HUYGENS PRE-ARRIVAL NEWS BRIEFING FOR IPOD

VIDEO: OVERVIEW OF HUYGENS PROBE'S SCIENCE OBJECTIVES QT
VIDEO: JULY NEWS BRIEFING ON CASSINI'S PICTURES OF TITAN QT
VIDEO: PICTURES SHOWING TITAN SURFACE FROM OCT. FLYBY QT
VIDEO: WHAT'S KNOWN ABOUT TITAN BEFORE THE FIRST FLYBY QT
VIDEO: NARRATED MOVIE OF CLOUDS MOVING NEAR SOUTH POLE QT
VIDEO: OCT. BRIEFING ON RADAR IMAGES OF TITAN SURFACE QT
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Ares 1-X Patch
The official embroidered patch for the Ares 1-X rocket test flight, is available for purchase.
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Apollo Collage
This beautiful one piece set features the Apollo program emblem surrounded by the individual mission logos.
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The official embroidered patch for the International Space Station Expedition 21 crew is now available from our stores.
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