Talk:Huygens (spacecraft)

Findings section
The info in the findings section about whether or not there is a liquid ocean is at odds with the info on the main Titan page.

I made some minimal changes to help resolve this to some degree and added a reference to the "Lakes of Titan" article, while preserving some mention of early thinking on the issue. A more comprehensive revision is really required, however. — Preceding unsigned comment added by 58.173.242.91 (talk) 00:45, 17 August 2011 (UTC)

Microphone
"it will be only the second time in history (a Venera-13 recording being the first) that audible sounds from another planetary body have been recorded."

This thing about Venera-13 sounds very interesting but there's nothing about it on the (quite substantial) V-13 page. I would add it there but a (very) quick google search reveals nothing. Anyone have a good source for this?

Haukurth 14:09, 14 Jan 2005 (UTC)


 * The info site linked from the main Venera programme article mentions the microphone near the bottom of this page . No recording to listen to alas. adamsan 18:53, 14 Jan 2005 (UTC)

Sound from the landing can be heard on the ESA page:  —Preceding unsigned comment added by 193.10.251.236 (talk) 11:15, 24 October 2010 (UTC)

First image from Huygens
Is the "first image released" (Image:050114huygens1.jpg) for real? There's no mention of it at ESA or JPL, and the image has no source given. --Lancevortex 20:25, 14 Jan 2005 (UTC)


 * Yes this is a screen-capture of the live web-stream, I'm guessing a hi-res picture will be released around 23:00, or when the current press-event is over. Switcher 20:41, 14 Jan 2005 (UTC) edit Woops I was wrong, this is raw data. Full of artifacts and stuff, the hi-res images will be released during the following weeks if I am not mistaken. Huygens took aprox. 350 images, that a whole lot 'o images.


 * Yes, just saw it live on NASA TV. IT's now on the NASA site here: http://www.nasa.gov/mission_pages/cassini/main/index.html --Plek 21:16, 14 Jan 2005 (UTC)


 * Indeed it appears that I was too hasty with my suspicions! --Lancevortex 22:43, 14 Jan 2005 (UTC)


 * I've replaced the image from the landing site with a colour version from, feel free to revert if necessary. - Estel (talk) 17:56, Jan 15, 2005 (UTC)

Huygens probe early results
If anyone is interested here is a quick and dirty precised transcription of Claudio Sollazzo audio report (mp3 2.7MB). I assume Cassini_orbiter_downlink_of_huygens_probe_timeline.jpg A and B boxes refer to "Chain A" and "Chain B" that Claudio talks about?

Claudio Sollazzo is head of Huygens operations unit, who has been babysitting the probe for many years, from ESA, from GPL. As Jean Pierre (sp?) has announced we have seen data from at least the first half hour of descent. During entry phase. Parachute deployed 15 seconds earlier than prediction, very close to expected profile. We are waiting to see the History data, the telemetry that was recorded on the probe before even the back cover came off so we can reconstruct the atmospheric entry phase.

From Chain B batteries are Ok, computer, software and instrument states are all good. Internal probe temperature was 25 degress C, while outside was -180 degrees C, so our instruments were operating in a mild temperature. This explains the long life of the probe on the the ground.

The spin rate started at 9.5 revolutions per minute. and by the time we left it was 4.3 revolutions per minute. The variations told us that the third parachute was deployed correctly. When we left the probe was at 50 km altitude, and the radar altimeter was to be locked (?).

We have little information from Chain A, which we are investigating. The chains are totally independent, meaning there are effectively two independent probe, within the same housing - there is full redundancy.

The counter of lost packets was zero, meaning no packets were lost during the probe's transmission. Applause.

Audio ends at this point. -Wikibob | Talk 21:01, 2005 Jan 14 (UTC)

External links and why I edited them
Evil Monkey &rarr; Talk 00:22, Jan 15, 2005 (UTC)
 * www.futura-sciences.com is in French and just contains the images that are available from ESA/NASA and it is advertising
 * We all know what Huygens is, so the link description doesn't need to contain it (and was in the future tense as well) and the link pointed to a redirect
 * There isn't a need to expand NASA to the National Aeronautical and Space Administration


 * Don't you think, the Flash-Animation of Cassini orbits link belongs to the main Cassini page and not to Huygens?

Parachute
Information about parachute from. See for copyright status.

Image of landing site
I'm not very happy with how this looks when rendered on narrow browser windows. Can someone help with the picture placement? --Mmm 07:46, Jan 16, 2005 (UTC)

Huygens images
Given its distance from the Sun, plus cloud cover, the light intensity in Titan's atmosphere must be very low. Does anyone know how Huygens managed to capture such clear images - especially during descent, when speed of craft plus spinning would seem to rule out long exposure times ? Gandalf61 09:53, Jan 16, 2005 (UTC)
 * During the NASA TV coverage I heard someone say, that the light from the Sun on Titan is about 1000 times dimmer than here on Earth, but still 1000 times brighter than the full Moon. If that is true then there is more than enough light for modern CCD cameras. Awolf002 11:39, 16 Jan 2005 (UTC)

Correcting timings
I've changed the UTC times of the atmospheric to 10:13 UTC and that of landing to 12:43, using the Central European Time times from ESA (UTC+1). I'm now dubious of ESA's press release timings, so my change may need to be reverted! Here is a cross reference of the times various sources quote.

Event               ESA                     NASA Atmospheric Entry   11:13 CET =10:13 UTC Earth detects signal ....................... 2:25 a.m. PST =10:25 UTC? Green Bank detects  11:25 CET =10:25 UTC? Landing             13:34 CET =12:34 UTC    4:34 a.m. PST =12:34 UTC first data rxd      17:19 CET =16:19 UTC    8:19 a.m. PST =16:19 UTC

I'm now confused by both ESA and NASA releases, are they using a form of Spacecraft Event Time, where they adjust the times back to what they would be at Titan? If the probe enters at 10:13 UTC, then how can its radio signal reach Earth to be detected at 10:34 UTC?


 * Well, for detailed timeline in SCET, please see also Cassini-Huygens timeline. The probe entered the atmosphere at 09:06 SCET (11:13 ERT), and impacted with the surface at 11:38 SCET (12:45 ERT). Yaohua2000 00:34, 2005 Jan 18 (UTC)

Also, I would now like to check the transit times listed on Cassini-Huygens_timeline, so does anyone know how these were calculated? -Wikibob | Talk 14:36, 2005 Jan 17 (UTC)


 * I'm not sure how the transit times were calculated, but I can confirm that the contact times for earth and moon agree within 30 seconds with the results given by the Starry Night software package, based on the projected landing site coordinates. --Mmm 17:43, Jan 17, 2005 (UTC)


 * The contact times are calculated using JPL Horizons system. Please verify your work with Starry Night. Yaohua2000 00:34, 2005 Jan 18 (UTC)


 * I don't understand the last comment. Using Starry Night I saw times that agree with the posted times. I'm actually quite impressed with the accuracy of Starry Night. &mdash; Mmm 06:40, Jan 18, 2005 (UTC)

References for FA
If this had inline references, this could easily became a FA. Anybody would be willing to fix this?--Piotr Konieczny aka Prokonsul Piotrus Talk 22:34, 29 January 2006 (UTC)

Update badly needed
No way is this near-ready for FA. Portions are even still written in the future tense. It needs a recap of the actual scientific findings, which should all be available a year later. Fawcett5 05:54, 12 February 2006 (UTC)

Nixer's reverts
Please STOP reverting to your heavily edited titan surface image from huygens and claiming it is true color! It is NOT ture color and all you did was contrast enhance the ESA image. It is IMPOSSIBLE for the image to be true color. DISR only has a black and white imager and a visible and infrared spectrometer. The spectrum taken just before landing shows predominately orange light and that was used to EDIT the image so it appears orange too. IT IS NOT A TRUE COLOR IMAGE and your continual claiming so is completely factually incorrect.--Deglr6328 21:13, 12 February 2006 (UTC)


 * I have to agree with Deglr. Perhaps you could provide the source of the image, Nixer, so we could evaluate its claims? Also, I must disagree with this edit summary; it is clearly an artist's impression. Were it not to be, it would imply that some sort of camera device was already present in Titan's atmosphere, photographying Huygens as it descended; the inaccurate surface representation and view of Saturn, along with the computer-generated style, are further evidence that it is not a photograph. &mdash; Knowledge Seeker &#2470; 22:18, 12 February 2006 (UTC)
 * Yes, that image is an artist work, no dobt. I thought you mean the image from the surface I have uploaded. This image is a combination of the low-resolution color image made by Downward-Looking Visible Spectrometer with the higher-resolution black&white photo. The resolution of spectrometer allows it to make colour pictures with at least 4x4 degrees per pixel resolution. This image illustrates the process: [[Image:titanthree.jpg]]


 * The low-resolution color image is also included in a movie by ESA that illustrates the descent of Huygens.--Nixer 23:07, 12 February 2006 (UTC)


 * Interesting. Where did you obtain that image or the one you had put in the article? &mdash; Knowledge Seeker &#2470; 01:42, 13 February 2006 (UTC)
 * From Titan.--Nixer 02:09, 13 February 2006 (UTC)


 * How helpful. If you read the article detailing the DISR design you will see quite clearly that there are NO bayer masks and NO color filters anywhere on the imaging CCD's optical path. It is utterly impossible for disr to create *true color* images. All it can do is take spectra on the way down, say *this* is the dominant color and then colorize the B/W images with that color using possibly using some fudge factors for contrast etc. Thats it. I can't make this any more clear.--Deglr6328 03:30, 13 February 2006 (UTC)
 * From your source:

Azimuth Nadir     Spectral        Spectral           Spatial           Pixel Downward-Looking Instrument Range  Range  Range (nm)   Scale (/pixel)    Scale (/pixel)   Format Visible Spectrometer (DLVS)    4°       10-50°    480-960        2.4 nm                    2°          20 x 200


 * So the DLVS can produce visible light color image with resolution 20x200 pixels--Nixer 03:51, 13 February 2006 (UTC)


 * Yeah that is the area that a spectrum is taken on, 20X200 pixels. It is not making an image with spatial information on those pixels, it is merely an overlaid spectrum of what the input optic sees at any one time. And anyway the entire side looking imager images are only ~120X250! As the instrument platform moves and rotates you get some idea of different spectra coming from different locations but there is no way you're going to be able to recreate anything like a true color image. End of story.--Deglr6328 04:28, 13 February 2006 (UTC)
 * As I already said, the first image is from DLVS, the second - from HRI, and the third - is those combination. What do you not undestand? The documest says its resolution. The azimuth range of the instrument is 4° and spatial resolution 2°/pixel. Please do not show us your ignorance. I already cited the NASA source that also says it is true-color. Please do not vandalise the article. Your sence is not relevant.--Nixer 04:52, 13 February 2006 (UTC)
 * Hello!!? DLVS is the Downward-Looking Visible Spectrometer!! It doesn't produce images!!!!!! Get a clue! You're the one "vandalizing the article". --Deglr6328 05:34, 13 February 2006 (UTC)
 * This is your opinion, which in contravercy with facts and documents. If you download the movie you will find the same images in it. How can I vandalize the article with images released by NASA? :-)--Nixer 05:49, 13 February 2006 (UTC)
 * Ugh fine. do whatever. I'm not about to contact friggin' nasa. Though I still think its definitely WRONG to call these images anything like "true color".--Deglr6328 01:53, 14 February 2006 (UTC)

Reference
I like the two articles in Space Science Review from 2002 and I will add the first rsult references from Nature 2005 in short time!!Stone 21:44, 22 February 2006 (UTC)

First paragraphs
Please clean up and add links to the first few paragraphs. I also don't think the phrase "for lack of a better word" is best used in an encyclopedia.82.25.175.134 18:21, 28 November 2006 (UTC)

Amateur contributions
The first sentence in the last paragraph reads "The Huygens Mission like no other space mission before could benefit from amateur contributions." This is false. What about the Cassini images, or the MER photos? They are also public. The sentence needs revising, maybe to "The Huygens mission benefited significantly from amateur contributions? I'll change it in a week if no one objects.--Planetary 21:34, 7 January 2007 (UTC)

Surface Science Package
The section on this states the following "The Huygens SSP was developed by the Planetary and Space Sciences Research Institute (PSSRI) of the UK Open University and the Rutherford Appleton Laboratory Space Science Department under the direction of Professor John Zarnecki." Can I ask where this has come from as the work on the SSP was done at the University of Kent under the direction of John Zarnecki who didn't move to the Open University (along with most of the rest of the Space Science Department) until 2000, well after the launch of the probe. Ben W Bell  talk  09:23, 1 March 2007 (UTC)

million kilometres
The overview makes a reference to "1200 million kilometres". This is an incorect way to display an SI unit, especially one of a scientific nature. Would anyone object to me changing it to "1.2 terametres"? --Ceaser 21:42, 16 March 2007 (UTC)


 * That's actually a fairly standard way to represent numbers like that, since "billion" can have different meanings in British and American English. While technically correct, nobody actually uses terameters so most people probably won't understand the unit. We're writing for a general audience wherever possible so we should try to use the most commonly understood units. Bryan Derksen 00:25, 17 March 2007 (UTC)


 * I concur. Remember the audience. Very few people even in the scientific world use terakilometres, 1200 million kilometers is good enough so people can understand the article. Ben W Bell   talk  08:33, 17 March 2007 (UTC)


 * But how will people learn if you don't challenge them? You've stated that my suggestion is correct and I do agree that most people are not familiar with the term, however, this is a wiki.  Could you not simply link to the appropriate page informing readers of the term they don't know?  Further I would challenge that this is a very good page for this sort of thing.  The information is technical of nature, more so than say a page on a particular government or specific movie.--Ceaser 02:16, 19 March 2007 (UTC)


 * It's not a term that is widely used, even in the scientific community who would be more likely to know of it don't tend to use it. Ben W Bell   talk  08:16, 19 March 2007 (UTC)

How is "Huygens" pronounced?

 * Would it be appropriate to include a pronunciation guide early in the article for those of us who have not yet heard it pronounced correctly? Thanks in advance. --RayBirks 20:35, 2 April 2007 (UTC)


 * (pronounced in English (IPA): ; in Dutch: ) would be a good suggestion! I never heard it pronounced well either, even when I try it!--Stone 14:03, 3 April 2007 (UTC)

Bacterial Contamination
I came here to read about the possibility of terrestrial bacterial contamination of Titan. I found an ESA source commenting on it, perhaps it can have a place in this article; http://www.esa.int/SPECIALS/Cassini-Huygens/SEMAO72VQUD_2.html Rip-Saw 17:22, 20 August 2007 (UTC)

Huygens CD-ROM?
There should have been a CD-ROM within the Huygens. Does anyone remember this? They collected some messages via Internet back in 1996 (or something) for the CD. Urvabara (talk) 13:15, 24 January 2008 (UTC)
 * OUI, ayant travaillé sur la sonde Huygens, je confirme qu'un CD-Rom gravé avec de très nombreuses informations, dont des messages d'enfants, a été fixé sur la sonde. Il est maintenant sur le sol de Titan.--Friendly, Kasos_fr (talk) 23:10, 24 January 2008 (UTC)
 * I do not understand. Please, can you translate that to Finnish, Swedish or English? Urvabara (talk) 10:06, 31 January 2008 (UTC)
 * YES. Having worked on the Huygens probe, I confirm that a CD-Rom was fixed on the spacecraft, before it leaved the Friedrichshafen plant of Dornier Flugzeugwerke, probably on march 26 1997, date of the official delivery of the probe to NASA. This CD was engraved with a lot of messages collected on Internet, probably by NASA. But I have no information, where it is in NASA (or a possible web site). But I know some young children in France, in Tourrettes-sur-var, France, who participated. —Preceding unsigned comment added by Kasos fr (talk • contribs) 14:53, 31 January 2008 (UTC)
 * Thanks! Could someone add this info about the CD-ROM to the main article? Urvabara (talk) 07:05, 2 February 2008 (UTC)

Actually, the CD-ROM in question was installed on the main bus (the Cassini of Cassini-Huygens) and has burned up along with the orbiter. Here's the link: http://www.planetary.org/get-involved/messages/namesinspace.html#cassini Swilliamrex (talk) 17:33, 3 June 2019 (UTC)swilliamrex

A critical design flaw resolved
"when Huygens was to descend to Titan, it would have accelerated relative to Cassini, causing its signal to be Doppler-shifted" - this is not quite correct, it's not acceleration that causes Doppler effect, it's the relative velocity along the axis separating the two spacecraft. --Nasorenga (talk) 15:12, 2 April 2008 (UTC)
 * Yes. Perhaps this could be changed to "causing the Doppler shift of it's signal to vary" Vegasbri (talk) 13:57, 20 March 2009 (UTC)
 * Edit made. Vegasbri (talk) 14:03, 20 March 2009 (UTC)

infobox photo caption: "scale replica"
The caption on the photo in the infobox currently reads, “A scale replica of the probe, 1.3 metres across”. I assume it means that the replica is the same size as the probe, but if so, why use the term “scale”, which generally means reduced in size but in such a way as to maintain proportions. --Mathew5000 (talk) 19:22, 8 August 2009 (UTC)

The term "Ground" in the Overview
When describing the data chain from the probe to the earth, I find the use of the word ground confusing. From the article:

"The PSE included the electronics necessary to track the probe, to recover the data gathered during its descent, and to process and deliver the data to the orbiter, from which it transmitted or 'downlinked' to the ground."

I think that in this case, it is not immediately clear that "ground" refers to the Earth, as we are talking about a probe that will land on the ground of Titan. And when I'm flying above another celestial body, (which I am in my head while reading the article) the word ground makes me think of that body. I wouldn't consider myself to be "above the Earth", even though technically, I always am. I know that this "ground" term has a special meaning in NASA jargon, but I don't think it's clear, especially to non-Americans. I think it should be changed from "ground" to "Earth".


 * Don't be afraid to be bold and change it yourself. Besides, it's generally a more effective way of generating discussion if there's any one else thinks differently. ChiZeroOne (talk) 14:00, 15 May 2012 (UTC)

Misinformation in photo description
Surface photo description states: In situ image of Titan's surface from Huygens—the only images from a planetary surface beyond Mars which doesn't seem to be true, as Venera 13 provided photos too. Moreover, I can't say that Titan's surface is exactly planetary, but that's only matter of definition. — Preceding unsigned comment added by 89.69.52.12 (talk) 18:36, 31 March 2014 (UTC)
 * Venera 13 sent images from the surface of Venus, which is not "beyond Mars," if you accept that in this context, "beyond" means "further from the sun than." 174.24.42.240 (talk) 22:53, 5 September 2014 (UTC)

Paucity of surface images
How many images were transmitted from the surface? Disappointingly, the article has only one such image. Where can I go to see more? 174.24.42.240 (talk) 22:53, 5 September 2014 (UTC)
 * +1 67.198.37.17 (talk) 17:31, 10 July 2017 (UTC)

Landing site image
I have commented out a reference in the text to the image of the landing site, as the image was deleted in June. However, as it was deleted for having no source when it did actually give a source I have asked for the image to be restored:. If/when the image is restored I will restore it, and the text I commented out, to the article. Thryduulf (talk) 21:03, 12 November 2014 (UTC)

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Science findings?
The article is very slim on the actual science. For example, what is the atmosphere actually composed of? Nitrogen? Something else? Any comments about isotopes? What was the wind profile, in the end? The temperature profile? How opaque were the clouds? How much aerosol was there, and what was it made of? 67.198.37.17 (talk) 17:36, 10 July 2017 (UTC)

Photos?
Are there more photos available to add to the article and if so, is it appropriate? Elmmapleoakpine (talk) 23:54, 18 September 2017 (UTC)

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