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Huygens Wind Experiment Salvaged
SeaDour writes "Earlier, it was reported that the data from a critical wind speed experiment onboard the Huygens probe to Titan was completely lost due to someone forgetting to turn on one of Cassini's communications channels. However, it now appears that ground-based radio telescopes from the National Radio Astronomy Observatory were able to record the transmission's many subtle doppler shifts and reconstruct that lost wind data. The winds altered the probe's horizontal rate of descent, thereby producing a change in the frequency of the signal received on Earth. Additionally, the resolution of the radio telescopes was good enough to track Huygen's position to within one kilometer, allowing for the creation of a three-dimensional model of Huygen's descent."
That we have equipment sensitive enough to track a probe's position to within *1* km all the way out on Titan..
saying it seems rather bland but when you think of how many millions of miles away it is, I think it's pretty remarkable.
...the scientist who forgot to switch the experiment on, making "wooshing" sounds into a mike. "We got the data back, nothing to be embarassed about here, no sirree!"
if anyone at nasa is dumb enough to read slashdot : you guys rock !
Seriously : most people would give up, blaming someone else. It takes a true fighting spirit to try and recover from what someone else has fucked up.
When will I end this grieving ? When will my future begin ?
that's the first diagnostic question I always ask when fixing something.
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The receiver on the Cassini spacecraft didn't get turned on, but some very smart chaps here on Planet Earth listened very hard using some very expensive equipment and managed to hear the faint transmissions from Huygens anyway. Does that make more sense?
In Soviet Rush, today's Tom Sawyer gets high on you.
A whole lot more than 10; read the Planetary Society's account of just what it took to get the data back:
o -t racking_0207.html
http://www.planetary.org/news/2005/huygens_radi
Plus, they didn't know that this would work beforehand.
Dear Lord: One of your creatures may be hurt tonight. Please let it be the other creature.
The Star Trek:TNG writer's manual called for you to use the word TECH every time you needed a word like that; they got their science advisor to fill it in later.
So you really would see scripts with "Captain, I can compensate using TECH to TECH..."
I can't help but think that the series would have been better if TECH hadn't been such a cop-out. Sci-fi is about people, not technology, but often it's about how people interact with technology. If you don't know anything about technology then it's just the way people interact with mumbo-jumbo.
It's just you. ;-)
Seriously, if you think about it, this makes perfect sense. The Earth is a rotating sphere, right? So unless an object approaching ground level happens to maintain a perfectly geosynchronous orbit around the Earth as it falls inward, it will hit the atmosphere at an angle and not straight down. So almost inevitably, there will be a horizontal component (think the base of the triangle where the trajectory/vector is the hypotenuse) to go with the vertical component. How much and in which direction(s) the object is deflected from its ordinary horizontal state (the result of the pure angle of entry into the atmosphere) gives direct indication about the presence, speed, and direction of any wind which might exist at that place. (Vertical deflection from standard gravitational acceleration gives important information about the stratification and density of the atmosphere in the same manner.)
Does it make more sense now?
This hasn't gotten as much coverage, but a design oversight nearly cost all Huygens data. Doppler shift was not accounted for in the signal decode process. The mission plan had to be rewritten to find an alternative flight path that reduced the Doppler shift to within the limited acceptable tolerances. Fortunately, Cassini's approach to Saturn was accurate enough that enough fuel existed to allow this while preserving the latter part of the existing flight plan.
e /oct04/1004titan.html
Of course, in retrospect, maybe earth-based monitoring would have come to the rescue in this event, in an even bigger fashion.
"Titan Calling: How a Swedish engineer saved a once-in-a-lifetime mission to Saturn's mysterious moon"
http://www.spectrum.ieee.org/WEBONLY/publicfeatur
Sorry if this is a repeat. Slashdot's search 503-ed on me.