[X] My Assistant

[Wyl2006]

I am wondering about two special things:


1. Why was the Imager system of Cassini not set on a scan platform? I am really wondering that more than the half possibilites for RADAR-cartography are lost to do other experiments? This seems not an excellent technical solution.

2. Why was the Huygens camera build with such bad resolution? Also the "test images" done at the LPI parking area would give a lot of questions if people were not said that these things in the picture are trees.

Some experiments with a simple CCD-camera at 1/1000 of the illumination given on Earth shows clearly that better pictures could be done without problems, and there are better compression algorithms.

As the soviet space probe has shown during the 70s and 80s, it is possible to make panorama photos from a torrent surface during a flyby of the bus without serios problems.

I am really wondering on those funny self beloving of some ESA-"professionals" and the things told about these bunch of lousy photos they have gotten.

Some experiments with a simple CCD-camera at 1/1000 of the illumination given on Earth shows clearly that better pictures could be done without major problems.

I am working on that topic making cameras for supervision and examination for night and day.

Greetings: Wyl

[ngunn]

I'm amazed that anyone's grumbling. As was pointed out at the time the extra data channel was designed for redundancy, not for extra data. Since the landing was successful and one channel worked the Huygens engineering team delivered the goods 100%: a wonderful example of human exploration working at full stretch - daring ambition, technical thoroughness and a real dash of luck with the place of landing. As for the pictures they're a superb first peek at a whole new and very strange environment - quite magic, I say.

On lucky landing locations: how likely was it that Spirit would descend right in the middle of dust devil alley?

[The Messenger]

I'm amazed that anyone's grumbling. As was pointed out at the time the extra data channel was designed for redundancy, not for extra data. Since the landing was successful and one channel worked the Huygens engineering team delivered the goods 100%: a wonderful example of human exploration working at full stretch - daring ambition, technical thoroughness and a real dash of luck with the place of landing. As for the pictures they're a superb first peek at a whole new and very strange environment - quite magic, I say.

On lucky landing locations: how likely was it that Spirit would descend right in the middle of dust devil alley?

100% is a stretch: The DWE was lost, and even though some of this was recovered by the big ears on the earth, there are still unconstrained parameters and a lot of guessing about the orientation and timing of the DISR images. Bruce also told us that (some/all (?)) of the close spectra that were planned to be collected just before landing were lost - that hurts! Throw in the counter-rotation, and there was a significant loss of scientific data...albeit any and all complaints have to be tempered by the bonanza of information gathered...and hopefully, some day shared.

[ngunn]

100% is a stretch: The DWE was lost, and even though some of this was recovered by the big ears on the earth, there are still unconstrained parameters and a lot of guessing about the orientation and timing of the DISR images. Bruce also told us that (some/all (?)) of the close spectra that were planned to be collected just before landing were lost - that hurts!

I only said that the 2 Huygens radio channels were DESIGNED for redundancy. I know they weren't actually used in that way exactly. If I recall the comment made at the time was something like: "That's the scientists trying to screw the system." I read it in a press report - could have been New Scientist. If it's wrong I apologise. Still I don't understand why the doppler wind data wasn't on both channels. Why risk a whole experiment in this way?

[Bob Shaw]

I only said that the 2 Huygens radio channels were DESIGNED for redundancy. I know they weren't actually used in that way exactly. If I recall the comment made at the time was something like: "That's the scientists trying to screw the system." I read it in a press report - could have been New Scientist. If it's wrong I apologise. Still I don't understand why the doppler wind data wasn't on both channels. Why risk a whole experiment in this way?

I think that's another case of disconnected mission planning, which appears to have been a bit more common on Cassini-Huygens than it should - not only did a radio link simply not get turned on, but they came close to losing the whole Huygens mission as a result of getting the Huygens to Cassini comms design wrong! OK, things like ITAR can't have helped - but the very presence of ITAR restrictions should have acted as a warning sign that any sort of interface (including comms) issue needed to be given a lot of attention. These are managerial failures - it's the job of the managers to direct the technical staff!

Bob Shaw