Mike Hord wrote:

> Right on.  Per NPR, the temperature inside Huygens was "room temp"
> even after it touched down.  In fact, Huygens continued operating and
> transmitting data FAR longer than expected; so long, in fact, that rotation
> of Titan carried it out of range of Cassini.  Upsetting, since more data
> is always better, but at least we know that we got the maximum bang
> for our Euro (since it was an ESA program, after all ;-)).

Considering the flight crew "forgot" to turn on the second data 
transmitter, exactly half the data possible was lost due to human error.

I'd say you only got 1/2 of the maximum bang out of those Euros, but 
still a very commendable job.

They did lose half their expected data from Huygens, though.

http://www.space.com/missionlaunches/huygens_update_050115.html

One of the AMSAT guys was hunting for the frequencies used and found 
this interesting follow-up story that doesn't get much press overall in 
the euphoria surrounding a "successful" mission about another "almost 
major screwup" that would have made the Huygens portion of the flight 
VERY unsuccessful.

It's the story of a major flub in the Cassini receiver design that was 
found mid-flight and the engineer who pushed hard, despite massive 
political resistance, to do full testing of a potential problem 
regarding the receiver on board Cassini that received the data from 
Huygens who ultimately saved the entire Huygens flight.

There's an interesting mid-flight correction the Cassini-Huygens team 
did to make up for this massive receiver deficiency that wasn't found 
until AFTER launch.  (I can't say what or I give away the story, but 
cool that they were able to overcome bureaucratic inertia -- and real 
inertia (GRIN, you'll see) to come up with a work-around.)

http://www.spectrum.ieee.org/WEBONLY/publicfeature/oct04/1004titan.html

Hint: Doppler + Microwaves = fun.  ;-)

There's also this:

http://saturn.jpl.nasa.gov/mission/nav-doppler-effect.cfm

Which descibes how the oscillator on board Cassini is VERY accurate to 
allow tracking of Cassini via Doppler effect of its RF signals.

As one AMSAT member put it on AMSAT-BB today: (paraphrased) This is yet 
another lesson that major projects like this one should use as much 
open-source code as possible and get peer reviews done.

I agree - especially the latter.

The ESA guy in charge agrees with the latter point too:

'Louet said a Huygens Mission Operations Plan sent by ESA to Cassini 
managers at NASA's Jet Propulsion Laboratory contained improperly 
written and confusing information. "JPL executed the instructions we 
gave them," Louet said. "One lesson we hopefully will draw from this is 
that you need independent reviews of all systems. It's a classic example 
of the most-simple things escaping review because they are simple."'

The Mars landers were a major recent exception to the closed-source 
software mentality of spaceflight systems.  Wicked cool software there, 
man.  It's neat to be able to play with the command and control software 
console on any Java-capable box, and considering they're government 
research projects, it's certainly appropriate that the source for all of 
these missions (as much as possible without compromising spacecraft 
command and control functions, of course) comes back to the citizens of 
the country at least, if not the world.  We paid for it, after all.

A lot of people have forgotten about the media hub-bub and controversy 
surrounding the Cassini launch (mostly misinformed if you ask me) 
because of the need to power deep-space probes with nuclear energy.  I 
was sitting here thinking about how many people were hearing about that 
in 1997 during newscasts and how completely insignificant it is today.

http://www.csulb.edu/~rodrigue/aaas99.html

Good clean fun, for sure!

Nate Duehr, nate@natetech.com
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