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View Full Version : Huygens Data Used to Measure Titan's Pebbles



Fraser
2006-Jul-26, 03:32 AM
When ESA's Huygens probe landed on the surface of Saturn's moon Titan last year, it continued to transmit data for 71 minutes. The signal relayed through Cassini had a strange fluctuation in power as the angle between the lander and spacecraft changed. Researchers were able to reproduce this power oscillation when they realized that the signal was bouncing off of pebbles on Titan's surface. They were able calculate that the surface around Huygens is mostly flat, but littered with 5-10 cm (2-4 inch) rocks.

Read the full blog entry (http://www.universetoday.com/2006/07/25/huygens-data-used-to-measure-titans-pebbles/)

Hamlet
2006-Jul-26, 02:12 PM
This is impressive! Not only did they solve a mystery, they've added useful data and have created a new technique for future missions. Quite a nice bonus. My hat's off to the research team!

Jerry
2006-Jul-30, 10:44 PM
It is a great example, but a puzzle remains: I wish they would have published a graph showing the signal strength attenuation and recovery, because the attentuation actually started ~30 minutes BEFORE the pubished Huygens 'landing time'.

FWIW, I think that their interpretation, that ground reflective interference as Cassini approached the Titan limb, caused both constructive and distructive interference, is correct. I still think the published landing time is wrong. Otherwise, why did reflective interference start long before the probe hit the surface?

Hamlet
2006-Jul-30, 11:08 PM
It is a great example, but a puzzle remains: I wish they would have published a graph showing the signal strength attenuation and recovery, because the attentuation actually started ~30 minutes BEFORE the pubished Huygens 'landing time'.

FWIW, I think that their interpretation, that ground reflective interference as Cassini approached the Titan limb, caused both constructive and distructive interference, is correct. I still think the published landing time is wrong. Otherwise, why did reflective interference start long before the probe hit the surface?

Where in the article did it say anything about the signal changing before Huygens landed? Everything in the article talks about the signal after the probe was on Titan.

Huygens landed on Titan at 11:38:11 UTC. Cassini continued to receive a signal until 12:50:24 UTC. This jibes with the approximate 71 minutes mentioned in the article. Where did the 30 minute number come from?