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Originally Posted by Jerry
Seriously, a Doppler signal that clearly demonstrates Hugyens landed at the correct time (or the moon stopped) absolutely kills my theory.
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Parkes Tracking of the Huygens Probe:
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Originally Posted by John M Sarkissian, Operations Scientist
When Huygens entered the atmosphere of Titan, the giant Greenbank telescope in West Virginia, USA, was poised to detect the signal when the transmitters sprang to life. Right on schedule at 9:18 pm (AEDT), Greenbank reported detecting the signal. A quiet cheer went up in the Parkes control room — we knew we had a mission.
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Originally Posted by John M Sarkissian, Operations Scientist
Both Greenbank and Parkes were equipped with spectrum analysers that allowed them to see the (Huygens) signal as a small spike in the pass-band of the receiver. It was this spike that Greenbank reported seeing. At Parkes, Doug Johnston had the capability to further process the data to produce plots of the carrier's Doppler-shift variations. The radio science receivers at Greenbank and Parkes were capable of measuring the Doppler shift of the signal in real-time.
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Originally Posted by John M Sarkissian, Operations Scientist
At 9:32 pm Doug reported seeing the glitch in the Doppler shift that indicated the main parachute had deployed on schedule.
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Originally Posted by John M Sarkissian, Operations Scientist
Doug had been viewing the plot of the Doppler shift variations, which only showed glitches when it departed from the predictions. Jim Border, decided to plot the sky frequency, that is, the actual frequency received. Sure enough, there was a large glitch at the suspected landing time of 11:45 pm. This confirmed the landing of the probe on Titan. Shortly after midnight, Jim and Doug alerted JPL and ESOC and the word quickly spread around the world that the probe had landed.Cheering erupted in the control room and congratulations were exchanged. The landing had been a much softer touchdown than expected and occurred sometime between 11:45 and 11:46 pm, 12 or 13 minutes later than expected. It was a second moon landing for Parkes.
The dish continued to perform flawlessly throughout the track until at 2:56 am Huygens finally set at Parkes, still transmitting strongly. The champagne was duly popped open in celebration. For this moon landing, the high winds were thankfully on Titan and not at Parkes.
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What the DWE's principle investigator
said about the Doppler data collected by the ground based telescopes:
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Originally Posted by Dr. Michael Bird
"Major mission events, such as the parachute exchange about 15 minutes into the atmospheric flight and impact on Titan at 13:45 CET, produced Doppler signatures that we can clearly identify in the data."
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Things that would have to be true for Jerry to be right:
1. Even though Titan pulled on Huygens much harder than predicted by Newtonian physics, Huygens magically hits the atmosphere on time anyway.
2. A "large glitch" in the Doppler data occurred, completely coincidentally, within 13 minutes of the predicted landing time.
3. Doppler data received before the landing "glitch" is inconsistent with a probe falling through the atmosphere while dangling from a parachute...and no one ever noticed this.
4. Doppler data received after the landing "glitch" is inconsistent with a probe sitting on the surface of Titan and instead looks a lot like the data received before the landing "glitch"...and no one ever noticed this.
5. We ignore every other excellent point that has been raised in this thread
The referenced article is not a "technical" article at all. It's more an informal recount of the work done tracking Huygens from the Parkes telescope in Australia. I think most reasonable people would agree that even just this article is evidence enough that we have a fairly good idea of the timeline of Huygens' descent (ie: the landing time isn't off by an hour).
I haven't religiously followed the Jerry portion of this thread but I believe, up until now, it's periodically been implied that various agencies are confused, dishonest or just plain stupid. But now it's real, published, accomplished scientists with names (and email addresses, and phone numbers, if you do a little searching) that Jerry has to say can't tell the difference between a probe falling through the atmosphere of Titan and a probe sitting motionless on the surface, using the
equipment they are responsible for operating, at the Parkes radio telescope.