Pretty sure that this effect would be velocity dependant, and more noticable for things moving at lower velocities (for large velocities you wouldn't notice it at all.) Do you have a functional form for your hypothetical potential?

As Hamlet has clarified, the penetrometers were ready-and-willing to measure impact as soon as the heat shield was deployed. The questions I have is 1) Did the penetrometer data include a time stamp. 2) What determined when the on-board computer started polling the penetrometers to see if they had measured an impacting force?
Operate, yes, but how often was the information polled and shipped to Cassini? I know I have read (or dreamed) that if Huygens is nearing the time-out window for transmitting data to Cassini, the surface science sequence will change and start monitoring according to landing and surface rules, rather than the descent sensing sequence. (There was no reason to poll and transmit the penetrometer data during the descent, waisting precious bandwidth.) Devil is always in the details.

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jwj

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

Hamlet has pointed out that the deployment time of the 2.9 meter parachute was an egg-timer function: Based upon the time at which Huygens reached the proper velocity to release the 8 meter parachute. I have pointed out many times that if the upper atmosphere was thinner, and the force of gravity greater, Huygens would plunge faster to a much lower altutide before popping the main parachute. The higher speed and lower deployement offset each other, resulting in a deployment time vary near the expected value, but at a much lower altitude.

In order for the 2.9 meter parachute to deploy at all without slamming into Titan, this deployment would have had to occur at an extremely low altitude, literally meters above the surface, and it would have resulted in an immediate rapid acceleration just before hitting the moon.

You can see this rapid acceleration in the last five seconds of the velocity plot extracted from the ESA's radar audiogram.

The time of landing is a sore spot. I know the penetrometers were designed to store the impact data and release it when ask for it - I know the computer would not have even been polling for the penetrometer data until it was convinced that the probe had landed, and I know it would have likely to continued to interpret the other accelerometer data as indicative that the probe was still airborn until the time-at-altitude table timed out.

I also remember reading, but I cannot find the source, that Huygens was supposed to broadcast a specia pulse series at the moment it landed, providing a calibration point. This same source contained the probe's time-out limit as well - a point at which is was suppose to start the surface science sequence even if it had not landed.

So my question is, was the time of landing indicated by detection of a Doppler shift, or a special pulsing of the transmitter? Does the Doppler signal indicate an acceleration that increased the velocity to a fairly high speed after the release of the 2.9 meter parachute or is the velocity surprisingly uniform? The answers to these questions are necessary before you can rule out my rather improbable, but possible, scenario.

Every one, who has sat down with me and looked at the overlays from the Huygens image set can see that the images are of a dynmically changing scene of an explosive crater formation - they can see the venting lines along the seams, the central gathering ring of the heat blanket, and the way that the image of flailing electrical umbellical that was attached to the heat shield dynamically changes with swing of Huygens on the parachute...

This is such a great puzzle!

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jwj

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

Jerry, you have a kind of selective blindness to what others are trying to explaine you: Tassel has already give the anwers on the previous page!

I'll post again his source: http://www.atnf.csiro.au/news/newsle...ng_Huygens.htm

Already you proved that you don't want to search the data you claim you need (by the wat, now you have Huygens landing coordinates, it is up to you to prove that it has reached the ground faster) but you also don't want to see those data when they are bringed in front of your eyes! Not nice at all...

Again, that audiogram is not a real time one. "Last five seconds" on that audio file could mean anything!

At this point they came in sight of thirty forty windmills that there are on plain, and as soon as Don Quixote saw them he said to his squire, "Fortune is arranging matters for us better than we could have shaped our desires ourselves, for look there, friend Sancho Panza, where thirty or more monstrous giants present themselves, all of whom I mean to engage in battle and slay, and with whose spoils we shall begin to make our fortunes; for this is righteous warfare, and it is God's good service to sweep so evil a breed from off the face of the earth."

"What giants?" said Sancho Panza.

"Those thou seest there," answered his master, "with the long arms, and some have them nearly two leagues long."

"Look, your worship," said Sancho; "what we see there are not giants but windmills, and what seem to be their arms are the sails that turned by the wind make the millstone go."

"It is easy to see," replied Don Quixote, "that thou art not used to this business of adventures; those are giants; and if thou art afraid, away with thee out of this and betake thyself to prayer while I engage them in fierce and unequal combat."

So saying, he gave the spur to his steed Rocinante, heedless of the cries his squire Sancho sent after him, warning him that most certainly they were windmills and not giants he was going to attack. He, however, was so positive they were giants that he neither heard the cries of Sancho, nor perceived, near as he was, what they were, but made at them shouting, "Fly not, cowards and vile beings, for a single knight attacks you."

A slight breeze at this moment sprang up, and the great sails began to move, seeing which Don Quixote exclaimed, "Though ye flourish more arms than the giant Briareus, ye have to reckon with me."

So saying, and commending himself with all his heart to his lady Dulcinea, imploring her to support him in such a peril, with lance in rest and covered by his buckler, he charged at Rocinante's fullest gallop and fell upon the first mill that stood in front of him; but as he drove his lance-point into the sail the wind whirled it round with such force that it shivered the lance to pieces, sweeping with it horse and rider, who went rolling over on the plain, in a sorry condition. Sancho hastened to his assistance as fast as his *** could go, and when he came up found him unable to move, with such a shock had Rocinante fallen with him.

"God bless me!" said Sancho, "did I not tell your worship to mind what you were about, for they were only windmills? and no one could have made any mistake about it but one who had something of the same kind in his head."

"Hush, friend Sancho," replied Don Quixote, "the fortunes of war more than any other are liable to frequent fluctuations; and moreover I think, and it is the truth, that that same sage Friston who carried off my study and books, has turned these giants into mills in order to rob me of the glory of vanquishing them, such is the enmity he bears me; but in the end his wicked arts will avail but little against my good sword."

Here is a pdf file to the construction, testing, and mechanical/electrical layout of the penetrometer.

Did the penetrmeter include a time stamp?
Of course it did, why wouldn't it?

What determined when the on-board computer started polling the penetrometers to see if they had measured an impacting force?
Per the article posted above, a piezoeletric pulse.


No, the data would be released in real-time. When the penetrometer made contact, the computer started sending it's data. It's a simple computer interrupt. And as many people have all ready mentioned, the computer and data was not under the control of the time-at-altitude table.

Let's take this another step further. Jerry, let's try your "New Physics" in a real world process. Using this "New Physics", calculate what would happen if someone was to jump out of an airplane (on Earth) at 2000ft (610m), and open his/her parachute at 320ft (100m). Would you be willing to trust your new physics to actually try it? Would the person hover, after the chute opened, or come crashing to the ground?

(Metricyard assumes no responsiblity to crush bones/organs or death if this feat is tried)

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"The universe is driven by the complex interaction between three ingredients: matter, energy, and enlightened self-interest." - G'Kar

I have presented two pieces of direct, and one indirect:

1) The Optical density of only 1.5 at the surface of Titan is physically incompatible with the known atmospheric thickness and the expected density distribution at the known thickness: As reported by the Planetary Society, the nitrogen gas alone should have caused enough scattering at the surface to increase the optical density to near twenty. A more massive moon would concentrate more of the known atmospheric mass near the surface, reduce the scattering in the upper atmosphere, and produce this observed density profile.

2) The atmospheric scattering when the main parachute was suppose to be deployed, at 160km, must have been limited, or the atmospheric density on the surface would have been much greater. But the sky sensor detected a high level of scattering when this measurement was first taken. Using Newtonian dynamics, the first observation and this one are physically incompatible with known gas laws, and with a with a moon of Titan's density. Something isn't right.

3) The measured speed of sound, (which is less than expected), means the atmosphere is less active than predicted, further aggrevating the discrepancy with known physics. Higher kinetic energy increases the collision frequency, reducing the dependancy of atmospheric density distribution on pressure dynamics. A lower speed of sound means lower temperature, less stirring, and increases the disparity between measured scattering at "160 km" and the theoretical: It widens the gap between effects 1) and 2).

4) (Indirect) The radar measured depth of the craters (by Cassini) is consistent with the expected depth on a more dense and massive body.


To the best of my knowledge, this data does not currently constrain Huygens position in any plane well enough to state this with a high degree of confidence.

Hey, I am every bit as surprised to see the gold mylar as you are, if not more so. The probe came through a thinner than expected atmosphere, that is also slightly colder than expected. The atmosphere is non-oxidizing, and gold has a very high melting point, if it is nearly pure.

Even so, the blanket is a surprise. It might be the blanket from the inside of the shield, but I don't think so - it looks too much like the blanket on the outside - (I don't think the inside blanket would have had the gathering ring, clearly visable in the footprint.)

And look at the curiously "telephone pole-like" 'drainage' feature seen in several of the raw images. The creater of Space Canada said it is shaped like an airport landing strip. I can find very similar shapes in the cable distribution network under the hood of my car, and I am certain that there was a similar cable layout either between the heat shield and the thermal blanket, or on the inner side of the heat shield.

I have addressed this - the timing seems inprobable, but not impossible.

The evidence is a careful examination of both the graphs of the radar, and listening to the sounds - on the original sound track posted by the ESA (they have reduced the resolution, probably to conserve band width.),
you could actually hear the heat shield spinning around like a quarter on a table during the final ten seconds. If the heat shield was that close to where Huygens landed, the main parachute could not be far away.

Then an hour + lag time between when the probe landed, and the increase in methane may be real. An hour may seem like a long time, but thermalconductivities are very low at 93K, and three minutes - or was it seconds - seems like an awful fast rate to steam methane out of sand. This will be an interesting exercise to try to duplicate.

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jwj

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

You are quite correct, there must be some discrepancies between the predicted profile and some of the housekeeping data. I don't have an answer yet, but neither does the ESA - we are still waiting for details.

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jwj

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

How about dealing, instead of ignoring, the details Tassel provided?

Parkes Tracking of the Huygens Probe:

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Some try to tell me, thoughts they cannot defend,... - Moody Blues.

Now back to our regularly scheduled debunking. . . :roll:

The GC/MS folks had the foresight to have a heated inlet in case the probe survived landing. While on the surface the inlet was at 363 K, but cooled a little by the end of the ~1:10 of data acquired from the surface.

It means I don't know what NASA means when they say 'rescently'. If you read the sig event log, they have been mulling over something or some things significant for months without clearly stating what.

Trends are useful analytical tools. If Galileo's wheels started shimmering everytime it neared a moon, and so did Cassini's (near both Saturn's and Jupiter's moons) there might be a meaningful trend.

As always, the devil is in the detail. If the wheel associated with "roll" relative to the planet is the one always acting up, that would be a pretty good sign something funky is happening. Anyone care to provide the level of detail needed to scope this out?

That's true, they are not jet engines.

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jwj

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

Egg timer? What I pointed out was that the entire deployment sequence starts with the detection, by the CASU, of the desired acceleration. The drogue chute pulls of the aft cover. A few seconds later the main chute is deployed and slows down the probe below subsonic speed. About 30 seconds later the heat shield is jettisoned. 15 minutes later the main chute is jettisoned and the stabilizer chute takes Huygens the rest of the way.

You've asserted this many times without any evidence. How much lower? How much faster? How did Huygen's heat shield handle the increased heat load?

Your scenario sounds like one of Kipling's "Just So" stories. Everything adjusted itself to look like the original predictions, yet operated under "Jerry physics".

You said the heat shield was jettisoned 100 meters above the surface. This is 30 seconds after main chute deployment and 15 minutes before stabilizer deployment.

Really? How did you determine this. How did you analyze the compressed radar. What technique did you use. What assumptions did you make?

Yes, a sore spot for your fantasy.

You know these things? How? Did you read the post by Elias concerning the TAT?

You've yet to explain how the thin Mylar blanket could survive entry and what an electrical harness was doing attached to the heat shield and how it survived entry.

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"A mystic is a person who is puzzled before the obvious but who understands the nonexistent." -- Elbert Hubbard

Yes it does. You just won't accept it. The telemetry and radio telescope data show that Huygens took 2hr 27min to reach the surface.

You've got to be joking! Aside from the color, do we have anything to suggest that the Mylar was embedded with gold and in sufficient quantities to absorb that much heat?

It would be a surprise to the Huygens engineers as well. Here's what they have to say from here

The heat shield designers also expect about 10kg of heat shield material to ablate. Doesn't look good for your "theory".

The shapes in the image remind you of your car? Well, I guess we can't get anymore definitive than that. :roll:
Explain again why a cable harness is connected to the heat shield and how it managed to survive entry?

Don't you see the contradictions in your own "theory". You've made the atmosphere so thin that Huygens heat blanket survives the encounter and yet at the same time you claim it was slowed down enough to land without cratering and send back over 3 hrs of data. Nothing short of handwaving or magic makes these contradictions go away.

Let us know what you find out.

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"A mystic is a person who is puzzled before the obvious but who understands the nonexistent." -- Elbert Hubbard