This Spacenews image photo mosaic (scroll down the page to the Huygens full Landing Site Mosaic and enlarge it), I took it around and showed it to more than a dozen rocket scientists: Physicists, chemists, engineers, and statisticians - mostly PhD’s, the rest with a minimum of twenty-five years experience in the industry. (I'm lucky; I live and work in a community where I can do that.) A curious thing happened:

If I held the image a ways away from them, made them focus on the scene from a distance and I said "check out this Blast Crater", they could immediately see the pattern of a round object colliding with a flat, dry hardened surface. They are familiar with this type of image. They could see the rounded, slightly oblong pattern of a heat shield plowing into the surface, raining charred ablative material to the sides, and spreading stress cracks along the edges.

You can tell the stress cracks were caused by the impact, because some of the cracks that are visible underneath the black dust were still spreading as the black dust was pelted onto them, vibrating the dust into a pattern that looks like Anasasi rock art.

But most obvious evidence is the remnant of the protective thermal blanket that covered the Huygens’ heat shield. The blanket is left like a ghostly image on the side of the small impact crater Huygens created as she skidded in. You can even see the radial pleating about the center of the heat shield, which looks like partial ellipse at the ‘bottom’ of the whiten ghostly image.

When I then ask them for an opinion as to whether it was something landing or taking off, the answer, was usually ‘landing’ because the distribution of charred particulate is not quite symmetrical. When I told them NASA had published a different opinion, stating that these were kilometer-scaled rather than centimeter-scaled images, some of them just chuckled. (Not at me, but at NASA.)

When I told one scientist it was where the Huygens probe impacted, he got suspicious and said, "Jerry, have you been playing around with some imaging software?" I assured him the images were not doctored and he could find everyone of them on the NASA website, and he said "It must be real then".

But if one of these scientists had already seen the images before I approached them, or if I first told them NASA was wrong and then showed them the images, they had a much harder time seeing an impact or blast crater. And the ones who knew I was working on a new fundamental theory, did not believe any of it, refusing to see or interpret anything at all.

The best example, though, is of an expert on stress mechanics, who was looking at the fractures radiating away from the crater. I told him the image was from Titan, and he started trying to figure out what the material is, because the pattern in the fractures is, in his worlds, "atypical." When I told him that the ESA says these are pictures of drainages from 8 km high, he insisted, "That's not from these pictures, I saw that one on the internet, and it was clearly taken from much higher." The image in front of him, was the image on the internet, in a completely different context - the correct one.

So I now have the informal opinions of more than a dozen rocket scientists that the pattern exposed in the composite images is a blast or impact crater. Isn't it ironic that several hundred scientists are wasting thousands of hours puzzling over these images because they have serious misconceptions about the altitude. They do not believe their own Doppler data, and they are relying upon there preconceptions of what should have happened to guide them.

Sometimes it does take a rocket scientist, but even scientists can be
betrayed by their own prior expectations.

So here, as best as I can reconstruct it, is what REALLY happened:

This entire scene photographed by Huygens is an impact crater made by the heat shield when it slid in at a slight angle. This whole series of images is in a circle no more than 7 meters across. The penetrometer data released by the ESA is right: When the heat shield hit, it fractured the thin crust of Titan and created stress fissures that look like rivers flowing into a lake or ocean.

"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.”

Not stated by the European Space Agency, but certainly found in the Doppler imaging, was greater acceleration than expected. It also took about ten minutes to fourteen minutes longer than expected to drop below mach 1.5 and release the main parachute. It then continued to fall at a reduced velocity, and as the atmosphere thickened, it gradually slowed to less than 15 m/sec. Huygens impacted in the crater with the heat shield still attached, and Huygens went into survival mode.

Edit: The following text replaced:
With this correction:

Not stated by the European Space Agency, but certainly found in the Doppler imaging, was greater acceleration than expected. It also took about ten to fourteen minutes longer than expected to reduce velocity below mach 1.5 and release the main parachute. As the atmosphere thickened, Huygens continued to fall at a reduced velocity but was still falling at a ~20m/s when the Doppler radar sensed the ground was within ~ 100 meters. The heat shield still attached, and Huygens went into survival mode.

As soon as the heat shield is released, a number of things happen. The ground radar is switched on, and in 30 seconds the three cameras shoot a sequence of pictures and relay them back to Cassini. This is so that, if anything unexpected happens, there will be a chance of recreating a visual sequence. These camera shots become the panorama of images documenting her landing from less than 100 meters. About seventy-two images shot in the last minute of Huygens flight form a panorama mosiac of a heat shield impact crater.

Releasing the heat shield assembly significantly reduced the weight, and the descent slowed to less than 1 m/s. ESA has told us that there was virtually no wind (< 1m/s), so the rest of the descent was almost completely vertical.


Huygens continued to snap pictures of the mudflat, and after ascending quickly to about thirty meters and leveling out under a very confused parachute, Huygens started the next phase of the landing, which was to deploy a smaller, three meter parachute and spider down from it. This occurs 12.2 seconds into the ground radar sequence as a pair of acceleration squibbles.

Twenty five seconds into the sequence the main parachute is jettisoned and there is a marked acceleration in Huygens downward motion. In the final thirty eight seconds of flight, Huygens comes to rest only a few meters from the impact crater, and pointed away from it.

Huygens was rocking, swinging and spinning as it fell and captured only these images of the descent. Thirty-eight seconds into the descent, Huygens was struck at by descending pyrotechnic or a bouncing heat shield. You can tell the probe was rocking and swinging, because the radar Doppler signal seems to pendulum and varies in two planes. The camera platforms rocked so high, the images look like long range vistas.

Fifty-four seconds into the ground radar sequence, you can hear the heat shield spinning down like a coin.

Seventy seconds after the ground radar was switch on, Huygens landed again, very close to where Huygens, while still attached to the heat shield, had landed the first time. The probe ended up about thirty feet away, pointing away from the muddy 'beach' she landed on, and towards a dry streambed.

The parachute(s) then fell about Huygens, and a lot of 'foggy' images were photographed during this sequence. The parachute ended up slightly bunched against one of the legs, clearly visible in a long series of ground shots draping over the bottom cameras lense. Huygens continued to take pictures as programmed, eventually filling the memory on either Cassini or Huygens.

We have every reason to be proud of the Huygens and Cassini team and the accomplishments of this little probe. For even though it did not bring home the panoramic images of Titan we all hoped for, this little pattern in the mud accomplished much more than any of us thought was possible, and will usher in a new era of physics.

Edit: Original entry contains a wrong discription of the heat shield release mechanism and therefore it is an impossible scenario. I changed the original sequence of events (that I placed on a prior thread) when ESA released a ground wind speed estimate of 5m/s, making the orginal scene implausabe. Today ESA revised that estimate down to less than 1m/s, and I have revised my version accordingly.

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jwj

It's ok not to know.

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When I am done here I think I will go create something from metal.

This claim is insane. If you look closely at the images from orbit, you can see the features in this mosaic. If you orient the images properly with respect to the images of titan's surface, you can see that the probe was right no target, and the 30 km scale of this mosiac means that these features should be observable in images like these. In fact, I've done a rough illistration using both of these images to show roughly which region of titan's surface we're seeing. Please, stop with these ludicrous claims, or at the very least leave them where they belong, in ATM.

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Due to the way the images were taken and assembled, you'll alwyas get a circular imprssion, no matter what you photographed. And showing blast crater experts an image and ask them for comments on the blast crater will surely make them seeing a blast crater. That's a Rorschach-test with suggestions and not science. If you would have shown it to some art-critics and ask them for comments on this recently discovered painting by Jackson Pollock, not one of them would go into lengths about blast craters.
Huygens has no legs. It was not designed for landing. It was just the way that the impact parameters made it a possibility that Huygens may survive it, as it did.

C'mon Jerry, give it a break and stop beating a dead horse that had never lived.

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"Flying in space is risky business, but just staying on this planet is risky business too." - John Young, astronaut

This really belongs in ATM. A few questions for Jerry:

What about the ground proximity sensor aka ground radar? According to plan, it was turned on at 60 km height, and recorded the altitude directly from that point on.

It also took about ten minutes to fourteen minutes longer than expected to drop below mach 1.5 and release the main parachute.

Since the parachute release was a timed event, how would this be possible? It might occur earlier if the g-switches triggered, but not later.

Huygens impacted in the crater with the heat shield still attached, and Huygens went into survival mode.

What is 'survival mode'? Reference, please - as far as I know, no such thing exists.

As soon as the heat shield is released, a number of things happen. The ground radar is switched on, and in 30 seconds the three cameras shoot a sequence of pictures and relay them back to Cassini, so that, if anything unexpected happens, there will be a chance of recreating a visual sequence. These camera shots become the panorama of images documenting her landing: About seventy-two images that form a panorama mosiac of a heat shield impact crater.

Since the probe according to this scenario had impacted on the ground, and the cameras are mounted in a fixed position, how could they shoot a panorama? The probe needs to spin to shoot anything but a fixed location, and an impact would cancel the previous spin. Further, if the probe was ascending, the changing perspective would be rather obvious and also make it impossible to generate a composite image from the resulting image sequence - an image wouldn't fit together if its neighbour was taken at a significantly later time.

Huygens' explosive bolts (containing the same type of charges used in ejection seats) jettisoned the heat shield, flinging Huygens ~60 meters into the Titan air, briefly entangling in the still descending main parachute, and taking it with it. This sequence is caught in the earliest Huygens images.

Reference for these explosive bolts? To my knowledge, the bolts were exploded simply as an effective way of severing them. This is a technique that's been used since the sixties. No need for spectacular pyrotechnics next to some very sensitive instrument either - if you put a compressed spring between probe and shield around the bolts, it would do the job fine and inertia would do the rest. Again, very old and proven technique.

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"We do not require reality to conform to the expectations of the ignorant"

Just how strong do you think the explosion of those bolts is? They are just strong enough to break the bolt, which has a thin wall at the point where the designers want it to break. An ejectionseat truly launches itself out of the cockpit, it's not like he just explodes the bolts connecting it to the floor.

Your reasoning is something like comparing a playgun gunpowder charge with Guy Fawkes' "private collection".

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The purpose of the explosive is to blast the heat shield far away from Huygens. The whole structure was designed with this in mind.

That's what I thought, but the animated descent sequence on the planetary society shows legs, as and they have been mentioned on the Huygens thread. The caption calls it "instrument configuration mode", so are they legs or not?

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jwj

It's ok not to know.

The sequence goes something like this:

Huygens deploys first parachute.

Heatshield bolts are severed.

Probe has a parachute to slow it's descent, so it floats down to the surface.

Heatshield (which is now seperate from the Probe) does not have a parachute, so it plummets at a signifigantly greater rate, "like a rock".

You don't need any fancy high-explosive bolts (or even springs) to accomplish this, as gravity and aerodynamics will solve the problem for you.

Here's a good math problem: How many kilograms of TNT would be needed to send the huygens probe flying 60 meters into the air on titan? 30 meters? 30 feet? What if they used C4?

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audentes fortuna iuvat

No. The explosive bolts are just for severing some connections. First, Hugens hung on the drogue chute. Then some bolts were cut and the rest dropped away from the back heatshield/drogue-chute assembly. Then the big main chute was ejected and then other bolts severed, so the main heatshield dropped away from the rest. No need to push some parts forcefully away from the rest by using explosives. I guess you confuse some stuff as the chute system was built by Martin-Baker, who has a pretty good reputation for their ejection seats. Or you confused it with the mortar which fires the chute through the wake of the probe so it could unfurl.
Maybe you confuse some instrument booms or the penetrometer with a leg. But Huygens definitely hadn't legs for landing, as landing was not a goal of the mission.

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"Flying in space is risky business, but just staying on this planet is risky business too." - John Young, astronaut

Why do people always insist on looking for alternate explanations to things that have plenty of data already? Instrument readings and data clearly tell us at what altitude the images were taken.

...John...

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-- Larry Niven

As said before, the bolts detach the shield from the lander, after which it is pushed away with a spring, which was "sandwiched" between lander and heatshield by the bolts holding the two together. The system is designed in such a way that it is capable of moving the heat shield away from the probe, the heat shield being the lighter part, and while both in flight. EDIT: indeed in a parachute config you don't even need springs. ANd it makes the need of explosive force for anything else than breaking the bolts certainly not need.

Just how many bolts would you need to fling the craft 60 metres into the air? I know, less gravity (but still 2 or 3 times more than tought :roll: :roll: ). Also, these explosions aren't directed.

I start to doubt the truth of your story in the opening post more and more, if you have informed the rocket scientists about this theory after you showed them the footage, and none of them questioned the explosive bolts. If it's true, you clearly need to look for other scientists .

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You got it 50% of it right.

The wishes, such as they were, were for a new thread, if absolutely necessary, although definitely not mandatory. You kind of got that part right.

But the wishes were also for its being where such a thread belonged, in Against the mainstream (ATM). You got that wrong by posting the new thread in GA.

Therefore, you got 50% of it right.

But at least that's a much better accuracy (by a very large factor) than than what's contained in your continued defense of your now discredited speculation.

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He's got it 25% right, cause he already had his own private Huygens problem thread. The aftermath of the events would have nicely fitted inthere (where it was at first in fact).

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To the regular visitor of internet bulletin boards it is clear that it's an excellent idea your parents get to choose your real name.

Statisticians are rocket scientists? That's right down there with your claim about metallurgists:

It was far from obvious to this one. BTW, in metallographic examination of cracks, there is no "dust". You are perhaps getting "dust" confused with Magnaflux™ and its various incarnations, which perform in just the opposite manner.

From what you've been posting, it would appear that this "community" you refer to exists only in a rather fantastic place.

How about dropping a few names to establish some credibility?

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This appears to have become a mantra for you. Repeat it enough times and you'll believe it's true.

Fortunately for the rest of us, we don't need mantras, we have knowledge and hard data.

Meanwhile, why not try this approach to your "new era of physics"? Take a good one, and flush all that misinformation out of your system.

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Jerry had a theory which the success of the Huygens probe disproves. So he needs to try and shoehorn that success into his theory now. Originally he said that Huygens would miss Titan entirely, or crash land if it did hit (in reality if his theory were correct the probe would not have made it very close to Saturn at all). To say that he is now grasping at straws is an understatement to say the least.

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