Huygens on Titan

[tw]

Originally Posted by Elspode

They may well *have* found something there that we don't have here. An ocean of methane on the surface, for starters.

The earth once was bathed in methane. That is part of the fascination with Titan. We may be looking at an early earth - which does not say Titan will grow into earth.

October's issue of IEEE Spectrum tells another story just as immense as the Huygens landing. The hero is Claudio Sollazzo who worried that Huygen's communication system had never been tested and Sweden's Boris Smeds who fought the bureaucracy to discover the Huygens Cassini communication problem. In simple terms, Doppler effect was not considered during spacecraft design. Once separated, Huygens had to transmit to Cassini that in turn relays that communication to earth. Huygens would enter the atmosphere as Cassini approached Titan. Smeds wanted to duplicate that data AND its varying signal strengths of a modulated signal. Repeatedly, the powers that be rejected the test as unnecessary as well as unnecessarily complex. But mission ground operation manager Sollazzo and project scientist Lebreton supported Smeds requests. Eventually, Smeds ended up in Goldstone CA (Mojave Desert) for two days of tests in 2000 when signals from Cassini took 48 minutes to be echoed. He discovered the radio signal was received, but that data (which bureaucracy said was unnecessary for the test) was distorted and unreadable.

Problem was in NASA's Cassini. IOW an Italian based company that made the receiver had compensated for Doppler effect in the carrier frequency, but had failed to do same to the decoder that extracts data from within that carrier radio wave. NASA had never reviewed the receiver design. The receiver had been designed sufficient for earth orbit but was not sufficient for Doppler effects in a deep space mission.

Cassini was originally to pass Titan 44 times. But the original launch was so accurate as to leave Cassini with sufficient fuel for course corrections. Cassini took a new, lower, and faster orbit of Saturn, dropped of Huygens, and then fired its rockets again to obtain the original course. Therefore Huygens was released from Cassini in December instead of November.

Now the story, as one can see, is quite technical but easily followed by one with basic science knowledge. IOW how many reporters really understood this story? Was Smeds in that Control Room in Darmstadt Germany on 14 January 2005? He should have been in a front row seat. And he should have been one of those stories adjacent to the big pictures from Huygens.