Key phrase, all data has been recovered. Ground stations monitoring Huygens managed to retrieve the Channel B data and reconstruction is underway. The first summary of high atmosphere doppler has already been released.

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I'm not completely heartless, the doctor who removed it told me he'd never be able to get it all.

And a chart showing almost 3.5 hours of GC/MS data on nitrogen and methane through the atmosphere and on the ground was already released at the second press conference a week after the mission.

No problem - the page dated Jan 14 is ambiguous at best as to what was known when it was posted, and it lacks the necessary detail: Minutes rather than seconds. Acceleration is all about seconds.

I did the calculations based upon the constraints ESA posted on December 21. The Interphase altitude is BY DEFINITION 1270 km, the PREDICTED velocity at entry, is 6000m/s. They expected to achieve MACH 1.5 at an altitude of 160km and a velocity of 400m/s, and they expected to do that in LESS THAN 180 seconds. Those are ESA parameters, not mine, and that works out to an average deceleration of ~16m/s.

Now increase the time periond to 228 seconds, plug in the same initial and final conditions and the average deceleration is less than half, which is what you would expect if the force of gravity was twice as strong. I guess the other possibility is it gives you enough time to slow down and take a picture of Hugh-the-mooning-Titanian and still meet your targets 8)

Good! Thank you, I'll check it out. FWIW shouln't the ground station should be listening to channel A, not B? That is what they expected to hear, and it is my understanding Huygens was talking, but Cassini didn't have her 'A' ear on.

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jwj

It's ok not to know. We should try harder to find out.

Jerry wrote:

Actually Jerry, the time taken from the Interface altitude (09:05:56) to the deployment of Main parachute (09:10:24) is 4min 28sec or 268sec. Not only do you not understand orbital mecahnics and linear equations of motion it now apears you can't even do primary school arithmetic.

How do you ever expect to be taken seriously on a Science based message board with such a careless approach #-o

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By asking questions we sometimes get the wrong answers, from wrong answers we learn to ask the right questions.

Hey, it's not only New Physics, but also New Math! :roll:

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Tom Lehrer:

Some of you who have small children may have perhaps been put in the embarrassing position of being unable to do your child's arithmetic homework because of the current revolution in mathematics teaching known as the New Math. So as a public service here tonight, I thought I would offer a brief lesson in the New Math. Tonight, we're gonna cover subtraction. This is the first room I've worked for a while that didn't have a blackboard, so we will have to make do with more primitive visual aids, as they say in the ed biz. Consider the following subtraction problem, which I will put up here: 342 minus 173. Now, remember how we used to do that:

Three from two is nine, carry the one, and if you're under 35 or went to a private school, you say seven from three is six, but if you're over 35 and went to a public school, you say eight from four is six ...and carry the one, so we have 169.

But in the new approach, as you know, the important thing is to understand what you're doing, rather than to get the right answer. Here's how they do it now:

You can't take three from two,
Two is less than three,
So you look at the four in the tens place.
Now that's really four tens
So you make it three tens,
Regroup, and you change a ten to ten ones,
And you add 'em to the two and get twelve,
And you take away three, that's nine.
Is that clear?

Now instead of four in the tens place
You've got three,
'Cause you added one,
That is to say, ten, to the two,
But you can't take seven from three,
So you look in the hundreds place.

From the three you then use one
To make ten ones...
(And you know why four plus minus one
Plus ten is fourteen minus one?
'Cause addition is commutative, right!)...
And so you've got thirteen tens
And you take away seven,
And that leaves five...

Well, six actually...
But the idea is the important thing!

Now go back to the hundreds place,
You're left with two,
And you take away one from two,
And that leaves...?

Everybody get one?
Not bad for the first day!

Hooray for New Math,
New-hoo-hoo Math,
It won't do you a bit of good to review math.
It's so simple,
So very simple,
That only a child can do it!

Now, that actually is not the answer that I had in mind, because the book that I got this problem out of wants you to do it in base eight. But don't panic! Base eight is just like base ten really - if you're missing two fingers! Shall we have a go at it? Hang on...

You can't take three from two,
Two is less than three,
So you look at the four in the eights place.
Now that's really four eights,
So you make it three eights,
Regroup, and you change an eight to eight ones
And you add 'em to the two,
And you get one-two base eight,
Which is ten base ten,
And you take away three, that's seven.
Ok?

Now instead of four in the eights place
You've got three,
'Cause you added one,
That is to say, eight, to the two,
But you can't take seven from three,
So you look at the sixty-fours...

"Sixty-four? How did sixty-four get into it?" I hear you cry! Well, sixty-four is eight squared, don't you see? "Well, ya ask a silly question, ya get a silly answer!"

From the three, you then use one
To make eight ones,
You add those ones to the three,
And you get one-three base eight,
Or, in other words,
In base ten you have eleven,
And you take away seven,
And seven from eleven is four!
Now go back to the sixty-fours,
You're left with two,
And you take away one from two,
And that leaves...?

Now, let's not always see the same hands!
One, that's right.
Whoever got one can stay after the show and clean the erasers.

Hooray for New Math,
New-hoo-hoo Math!
It won't do you a bit of good to review math.
It's so simple,
So very simple,
That only a child can do it!

Come back tomorrow night...we're gonna do fractions!

Y'know, I've often thought I'd like to write a mathematics textbook someday because I have a title that I know will sell a million copies; I'm gonna call it Tropic of Calculus.

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ROFWM@Maksutov =D> =D> =D>

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By asking questions we sometimes get the wrong answers, from wrong answers we learn to ask the right questions.

ESA Bulletin Nr. 92. Published November 1997.

Some of the info given in that bulletin was subsequently changed because of the need for a new landing date but fig 6 gives a prediction of the descent profile.



The bulletin also gives this figure for Titan's surface gravity

I think I'll stick with the published data and the mission success over your predictions Jerry

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By asking questions we sometimes get the wrong answers, from wrong answers we learn to ask the right questions.

Oh boy, I knew this thread would come to charts and math eventually

Doesn't everything?

It's all analytical geometry, you know... :wink:

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Thank you, transposition error. If you look back at my prior post, I had the digits correct, they were correct when I calculated the acceleration, and in any case, 268 seconds makes the problem worse, not better: they decelerated for 268 seconds rather than "less than three minutes", whatever that works out to in seconds ops:

I do make mistakes, especially on these post, and I appreciate the corrections, and I will keep making posts because I need to know when I am wrong.

The ESA has made corrections too: they changed no argon to argon, photos taken at 16 km to 13km, although there is still some ambiguity there. I would hope there is an explanation for why the descent from an entry altitude of 1270km, to parachute deployment took so much longer than they calculated. Maybe they need a BABB to help them, too!

Your graph does not include the path above 160km, which is the period I have been referring to.

What we really need is what we have needed for two weeks now: The same chart showing the actual descent, with an explanation for how they composed it - (did they use actual measured altitudes or estimates? How did they measure the altitudes? What did they use for a reference if they don't have Doppler data?

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jwj

It's ok not to know. We should try harder to find out.

Well Jerry, there you go again.

The fact that the parachute descent phase went 'flawlessly' (ESA words) ie it started at the altitude expected, the second 'chute deployed as expected, heat shield separated as expected and Huygens landed intact well within the timeframe expect has obviously escaped you attention.

Has it occured to you that a parachute deployment and landing are dependant on the gravity experienced by the parachute and object (man or space probe) that is attached to it? Yes, other things come into the equation as well, viscosity and density of the atmosphere, winds at various levels etc. but without a correct figure for gravity (in case you have forgotten, in Titan's case is Surface gravity 1.345 m/s2 as quoted above) the descent phase would have been a disaster even if the probe had got there, (which you predicted it wouldn't).

No, the graph I gave reference to does not show the aero braking of the heatshield and probe in the upper reaches of Titan's atmosphere because that line would be almost vertical on the scale of that graph but the whole of the Hugen's descent is influenced by Titan's gravity.

I will also point out that there were a number (six IIRC) of accelerometers recording the forces experienced by Huygens as it descended. Nothing, repeat nothing odd about Titan's gravity has been published and despite your atachment to your so called 'new physics' I suggest it is precisely that those readings were so ordinary and within expected parameters that they haven't been noteworthy enough to comment on in the press releases form ESA. Press releases that have given very high prominance to all the other extra-ordinary discoveries about Titan that Hugens has made.

I have no doubt that an highly accurate estimate of Titan's gravity (to more than the 4 significant figures widely quoted already) will be published in papers in due course. Will that more accurate estimate prove your speculations? Don't hold your breath!

You have been wrong all along, you were shown why you were wrong before Huygens even separated from Cassini, the mission success proved you were wrong, Cassini continues to send us pictures of Saturn and her moons and yet still you try to defend your case with fantastic claims, sloppy presentation of data and deprecating remarks about NASA and ESA staff.

In your own case, you have invented figures before so highlighting arithmetic errors or careless typos is quite legitimate.

Edit: added,

Regarding the time taken to traverse the upper atmosphere. I don't know if it's relevent or not (I haven't looked into it, yet) but we all know Huygen's flight plan was changed to keep it as perpendicular to Cassini (to minimise the Doppler frequency shift between the two craft during data transmission). This will presumably have affected the angle of descent and possibly the aero braking phase. The item I quoted (released in 1977) says it would last for less than 2 min wheareas we know it actually lasted 4 min 28 sec. The heatshield was also designed around a figure of 25% atmopheric argon (a figure that caused engineers some concern) This atmospheric argon estimated figure was later reduced to 15% and then 6% (much to the relief of the engineers) so perhaps the mission controllers felt they could safely make a longer descent at a shallower angle (and hence less g forces) and still achieve their goals. Maybe someone knows a little more about this aspect of the mission.

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By asking questions we sometimes get the wrong answers, from wrong answers we learn to ask the right questions.

...that this thread be locked??

Strike that. I'm actually learning from the other posters "counter arguments" and I assume that's why the BA hasn't locked this thread. :wink:

Awweee! He's fun to play with - in a cat and dead mouse sort of way 8)

Besides, I'm also learning a lot about the whole Huygens mission by looking at all the details.

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By asking questions we sometimes get the wrong answers, from wrong answers we learn to ask the right questions.

I should have added "and others"...as frogesque has pointed out, I'm not the only one learning.

I bet BA is havng a ball.

He (we) gets to see how a new theory shoud not be presented, and at the same time, see how many people keep posting in this thread, even though the posters are pretty much banging their heads against their keyboards.

BA is a sadist I say

I think he believes in the kindness of the human spirit. The fact that we haven't formed a mob yet is proof of our higher moral obligation to dispell idiocy and ignorance everywhere.

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Feynman
>~~~~<
Science is a way of trying not to fool yourself. The first principle is that you must not fool yourself, and you are the easiest person to fool.

Religion is a culture of faith; science is a culture of doubt.