View Full Version : Huygens lands on Titan

2005-Jan-16, 05:47 PM
Hi Everyone, A Happy New Year ALL.

I know what you must be thinking! :huh: Well the difference on this occasion is that the available images and science data from HUYGENS relayed to earth by the Cassini probe, was all handled by the European Space Agency, and this team are a little slow releasing the new data apart from the handful of exciting images of Titan’s surface. I must say that Fraser has done a great job tracking a lot of the photo's down. :)


Our story begins with the release of a map of relative surface brightness variations (Shown above) on Titan as measured in images taken in the 1080-nanometer spectral region in 1997 and 1998 by the Near Infrared Camera (NICMOS) on Hubble Space Telescope (Meier, Smith, Owen and Terrile, Icarus 145: 462-473, 2000). NICMOS images have scales of about 300 kilometres (186 miles) per pixel. The map colours indicate different surface reflectivity. From darkest to brightest, the colour progression is: deep blue (darkest), light blue, green, yellow, red and deep red (brightest). The large, continent-sized, red feature extending from 60 degrees to 150 degrees West longitude is called Xanadu. What we understand to be Huygens landing site is indicated too. ;)

With such a great surface reflectivity, planetary astronomers were already speculating that Xanadu was the larger of two cryogenic seas, and with the Huygens probe attempting to land at this location in mid January, confirmation was not far away. B)

The first analysis of Titan’s atmosphere appeared in Astronomy & Astrophysics magazine on 1 January 2005.


Those strange pure white clouds close to the moon’s south pole were analysed by astronomers: Antonin H. Bouchez and Michael E. Brown; Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA. They concluded that the continual presence of south polar clouds was consistent with the hypothesis that surface heating during the long period of continuous polar sunlight at the time of Titan's southern summer solstice, drives seasonal convection, and cloud formation at the pole. :unsure:

The clouds themselves account for 0.5% to 1% of Titan's 2.0 m flux, consistent with a global cloud cover fraction of 0.2% to 0.6%. Clouds observed over multiple-night observing periods remained nearly fixed in brightness and position with respect to Titan's surface.

However, clouds at Titan latitudes of 40 degrees and above could not be explained by the same process which led planetary scientists to suggest that two other classes of formation existed, one linked to surface geography, and the other to seasonally evolving circulation, which would be easily distinguished with continued observations over the next few years. The many images returned by the Huygens Titan probe has already shown surface topography in support of part of this theory. ;)

The Huygens Decent

© Kevin Dawson.

The European Space Agency probe Huygens began its plunge into Titan’s atmosphere on the early morning of 14 January aiming for the equatorial region known as Xanadu. Everything went well and the outside temperature was measured to be –200 degrees centigrade in the stratosphere, before rising to just above –183 degrees 10 kilometres (16 miles) above the surface of Titan. Here the 360-degree mosaic of b/w images returned by Huygens showed what appeared to be a long shoreline with liquid created channels or contributories, meandering down to a relatively calm cryogenic sea. B)


The cryogenic liquid channels (Shown above), reminiscent of those we have all seen in Martian images, became much clearer from Huygens at an altitude of 8 kilometres (5 miles), the 'Sea' is on the right)

The next image was oh-inspiring as Huygens viewed a misty landscape composed of methane haze slopping down to what may be the cryogenic Xanadu Sea. The sea of Xanadu -- if it is a sea -- would be composed of cryogenic liquid methane and ethane. Any waves would be up to twice the height of those of any sea on Earth, and the liquid would have the same consistency of thick tar-like oil. The wind speed has been estimated at around 6-7 kilometres (about 4 miles) per hour. :o

Huygens turned circle and landed on the surface of Titan angled at a relatively flat 20 degrees, and sent back postcards showing a pebble strewn landscape as far as its CCD ‘eyes’ could see. The onboard instruments indicated that the saucer shaped probe first landed on a surface crust, probably ice, that cracked, and Huygens settled down onto a sand type surface underneath. :D

The probe continued to transmit black & white images (over 330), and data to the passing Cassini spacecraft above, until Cassini lost the signal below the horizon. Huygens was not equipped with a colour camera, so the image team introduced the average spectral background data returned from Titan’s surface, to that of the b/w images to give a realistic colour photograph showing the orange smoggy atmosphere. :D :unsure:


Huygens as part of the Cassini NASA/ESA mission, was a great success, and the scientific data will keep planetary scientists busy for months to come. :)

Richard Pearson
Science Correspondent

Images courtesy of The European Space Agency
Huygens Probe Decent Graphic © Kevin Dawson

2005-Jan-16, 10:15 PM

I have just spent some time reading all of your contributions on the day Huygens landed on Titan. To many there was a lot of disappointment about the availability of images and data. Sadly the European Space Agency don’t do things on the same scale as NASA/JPL so that only a small amount of data was released, including images, even though their Headquarters were swarming with the worlds press. Even I had to bide my time in order to give an account of the historic occasion today.

What great UT-Forum teamwork, with everyone on line pulling together to find new images and news snippets. It is teamwork such as this that makes the Universe Today Forum one of the very best on the internet --- Priceless ! :) :D
I like the comment: “OK. Who forgot to pack the rover?” Some of the images did have a close resemblance to photo’s returned from Martian orbit, and that incredible view from Huygens’s landing site of the pebbled landscape.

There was the animated_gif and the question of snowflakes, followed by dave_f’s observation:

“Nice link. I didn't see snowflakes but I did get the distinct impression the wind was nudging the probe around a little bit.”

The wind measurement upon landing was given as about 2½ kilometres (4 miles) per hour that would be barely noticeable in Titan’s low gravity. Every time I tried to view the Gif I was timed out to a blank page?

Finally that excellent observation contribution from ssmythe that focused on the ESA press conference, and a point I had entirely missed, and many other journalists too:

“Another comment that came out was from a journalist suggesting that there was some finger pointing as to the loss of the A-channel because someone didn't write code to receive it. The ESA team kept on track saying there was going to be an inquiry to this and both ESA and NASA would be represented.”

Anthony Lienkens out performed the European Space Agency on his personal Blog site with dozens of Huygens stitched and mosaic images. Personal Blog web sites are a big thing now in many parts of Canada and the US. It just demonstrates that some of these sites deliver the goods, even out performing the highly financed government agencies.


2005-Jan-16, 11:17 PM
Thanks Richard. I've edited the topic title so that it's not all caps. Although it's obviously a momentous occasion, the rules do say no all-caps titles.

2005-Jan-16, 11:22 PM
Thank you richard0802 for you kind remarks regarding the UT forum. I am a relative necomer and I believe it to be the quickest way to get up-to-date info on current astronomical events and the physics behind them. The contribution (and patience of the contributors and moderators) to us "not so informed and educated" is nothing short of extrodinary. I for one rely on thier abilities to explain and give references to support and/or debunk the "many" confusing theories and points of arguments presented by many who join this forum to posit thier "new" revelations. Some are convincing and require a real open mind but in the long run, it forces the mind to search for the real scientific evidence and come away with a more enlightened view. I guess this is a thanks to Dr. Cain and the forum contributors.
What I really wanted to say is thank you for the "formal" update on this tremendous achievement and I hope to hear more from you soon.

2005-Jan-17, 01:12 PM
Whilst all this recent info about Titan has got me quite excited, I am also a little sad. We have just been given a great "keyhole" view to what looks like a very interesting place. The trouble is, that whilst I am sure a lot more will be learned from the data that has been sent there will be no more new material for a very long time. In contrast our knowlege of Mars seems to bounding along very nicely. Even if they started a project now to put a rover there, the time needed to design, built and test it, then the flight time I guess it would all take about 25 years. I am already in my 50s, so I guess the odds are against me ever getting to see any of the fuits of that.

2005-Jan-17, 07:12 PM
I just joined this site last night, while browsing the web for a little additional info on the Titan landing. I'm not an astronomer, amateur or otherwise, nor a biologist, chemist or engineer. Just a person who was fascinated by the idea of dropping an econo car on a rock a few hundred million miles from Earth, and sending back pictures and a wealth of other data as a bonus.

Richard, after reading a few dozen articles on the subject, yours was easily one of the best I've read. The descriptions, (so far as I understood them), the graphics, the narration of the descent, and the photos were all first rate.

Props to you!

John L
2005-Jan-17, 08:30 PM
Originally posted by Richard0802@Jan 16 2005, 05:15 PM
I like the comment: “OK. Who forgot to pack the rover?” Some of the images did have a close resemblance to photo’s returned from Martian orbit, and that incredible view from Huygens’s landing site of the pebbled landscape.
I agree. It's a shame they only had a few hours of battery time on board so that they only got data from the one pass of Cassini. I agree that a nice RTG and even just a mini-rover would have been nice. When you're going a billion miles in a possible once in a life time trip you should remember to pack everything you'd possible want to bring. Even if they just did a Pathfinder/Sojourner style search of the surrounding 20 feet we'd have gotten a lot out of it. The kicker was the low power the batteries could supply, though. Still, I like the pictures they've put out and I'm looking forward to the final images once they've been fully processed. I hope they don't sit on them for months, though...

2005-Jan-17, 09:10 PM
Originally posted by John L@Jan 17 2005, 08:30 PM
I agree that a nice RTG and even just a mini-rover would have been nice.
Perhaps next time... and while their at it, send a color camera, or at least some filters to make it possible to later generate color images.

My concern with the RTG powered rover on Titan is that I'd expect it to melt or vaporize the material under it pretty rapidly unless great care is take to insulate, isolate, and reflect up the heat coming from that thing. That doesn't make it impossible to build, but it certainly gives some new constraints.

2005-Jan-26, 03:26 AM
Just thought I would update you all on that collage I did.
Note the landing spot which differs from the top of this post.
Information has been verified from ESA website.

Kevn Dawson

http://spacescience.ca/titan/Titan_huygens_landing_site_mosaic_big_thumbnail.jp g

"They walked on our moon when I was born. When you were, born they put a probe on Titan's moon and started our Journey to Saturn." Collage dedicated to my unconquerable son, Cody Vincentius Dawson.

2005-Jan-26, 03:48 AM
Nice poster. Is it downloadable in a larger more detailed format?