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Cassini Probe Does Titan Flyby
EccentricAnomaly writes "Today, Cassini had its first close encounter with Titan around 8:30AM PDT. Data from the flyby will start coming down around 6:30PM PDT, and you can watch the pictures live on NASA TV. If you want higher resolution or just to stare at one picture for a while, the raw images will be put on the web right away, with pretty press images to follow the next day. And if you want to know about the observations planned for the flyby, you can read this PDF or watch this animation."
Subject: Cassini Image: Eyes on Xanadu
m ed ia/pia06107.html
s /SEMB2E 0A90E_0.html
From: baalke@earthlink.net (Ron)
Newsgroups: sci.space.news
Followup-To: sci.space.policy
Date: 26 Oct 2004 09:25:07 -0700
http://www.nasa.gov/mission_pages/cassini/multi
Eyes on Xanadu
October 25, 2004
Cassini image of Titan, revealing the bright continent-sized terrain
known as Xanadu
This image taken on Oct. 24, 2004, reveals Titan's bright
"continent-sized" terrain known as Xanadu. It was acquired with the
narrow angle camera on Cassini's imaging science subsystem through a
spectral filter centered at 938 nanometers, a wavelength region at which
Titan's surface can be most easily detected. The surface is seen at a
higher contrast than in previously released imaging science subsystem
images due to a lower phase angle (Sun-Titan-Cassini angle), which
minimizes scattering by the haze.
The image shows details about 10 times smaller than those seen from
Earth. Surface materials with different brightness properties (or
albedos) rather than topographic shading are highlighted. The image has
been calibrated and slightly enhanced for contrast. It will be further
processed to reduce atmospheric blurring and to optimize mapping of
surface features. The origin and geography of Xanadu remain mysteries at
this range. Bright features near the south pole (bottom) are clouds. On
Oct. 26, Cassini will acquire images of features in the central-left
portion of this image from a position about 100 times closer.
The Cassini-Huygens mission is a cooperative project of NASA, the
European Space Agency and the Italian Space Agency. The Jet Propulsion
Laboratory, a division of the California Institute of Technology in
Pasadena, manages the Cassini-Huygens mission for NASA's Science Mission
Directorate, Washington, D.C. The Cassini orbiter and its two onboard
cameras were designed, developed and assembled at JPL. The imaging team
is based at the Space Science Institute, Boulder, Colo.
For more information about the Cassini-Huygens mission, visit
http://saturn.jpl.nasa.gov and the
Cassini imaging team home page, http://ciclops.org
Credit: NASA/JPL/Space Science Institute
And
Cassini-Huygens makes first close approach to Titan
Today the NASA/ESA/ASI Cassini-Huygens spacecraft makes a fly-by of Saturn's
largest moon Titan - the closest ever performed.
Read more:
http://www.esa.int/SPECIALS/Cassini-Huygen
Interference has always been a huge factor, the Space Shuttle still used iron-core memory in its systems in the late 80s, because it wasn't affected by radiation. Can't just pop in some SDRAM and expect it to work out there.
> From NASA's faq - "Cassini stores the gathered information on two Solid State Recorders (SSR)
> with a combined capacity of 4 gigabits, about the volume of a compact disk (500MB)."
>
> It seems scientists are pretty confident that they can unload much data during Cassini's 9 hours
> downlink session.
>
> Imagine if there were some downtimes when earth communication cannot be established
> for a couple of days...
According to CNN that very problem exists. The buffers in those recorders are in danger of writing over the data before it can sucessfully be sent to Earth.
"The flyby of Titan was expected to go smoothly in space, but bad weather on Earth could affect Cassini's transmissions to the Deep Space Network, scientists said.
Cassini has only one chance to send data back to Earth before it is overwritten with data from its next set of observations, scientists said."
Not only will the Cassini be taking pictures, but its ion and neutral mass spectrometer will "scoop up" and sample Titan's atmosphere as it passes at a distance of 1,200 kilometers (745 miles).
"One important goal of this flyby is to confirm scientists' model of Titan's atmosphere to prepare for the Huygens probe descent," according to this article at SpaceDaily.com.
Sig cancelled due to lack of interest
The raw images may be higher resolution but guess what....they are also "raw"! That means they haven't been processed yet. The image data isn't very useful unless you have the necessary parameters / algorithms to process the data.
....responsiveness accross the CCD won't be the same and must be compensated for. I don't know if they've got a seperate grey calibration step (you'd need calibration data to reproduce it)....you could fiddle with tone curves yourself to make stuff pleasing to the eye / see different stuff.
There will be several steps in processing the image data, bad pixel correction (I guess these CCDs should have very few); white/black balance; tonal / grey calibration; others? I'd be surprised if there weren't a few others.
I guess the white/black balance is the most important thing I mentioned
Can anyone supply more details on the calibration?
So far as I know it's not worth downloading the raw images unless you want to exercise some bandwidth....I think that Nasa might give out the calibration data to some people (remember British scientists discovering possible new moon?)....Anyone know all the ins and outs?