Huygens shortlived?

...If the surface is slush-like
or tarry, a the usual wheeled rover isn't going to
make much progress and the liquid areas may have some
of the more interesting chemistry. In several of the
areas, the terrain looks like marsh with many channels
and small lakes. It will be a real challenge, but IMHO
what is called for is something amphibious, perhaps
even a hovercraft or a balloon. After all, since there
is an atmosphere, let's make use of it.

Indeed, given the low gravity and dense atmosphere, some sort of blimp
seems like might be the way to go. You could either just hang your
surface instruments off of it, or use it as the landing system for
surface probes, e.g., you fly around until you have found a good spot
to set down your rover. The latter would save you from needing a main
parachute in your landing system. I suppose the practicality of that
depends on the wind conditions. Winds were apparently fairly mild at
low altitude for Huygens, but are still largely unknown.

Power might be a bit of a problem too, as RTGs seem to be your only
long term option, and they have poor power to mass ratios, meaning your
blimp will be slow. Still, if you are content to drift most of the
time, and only do station keeping in low wind, that shouldn't be
impossible. The RTGs could also heat your gas envelope for improved
lift.

Steve Pope wrote:
My understanding is Huygens was designed to survive such
a landing and continue to function while floating in
hydrocarbons.

I could be mistaken however.

It was designed to have the maximum possible survival
rate in the event of a landing in liquid that the
designers could give it, within the design constraints.
However, this chance was not much. A pool of liquid
hydrocarbons at near liquid Nitrogen temperatures makes
an awfully efficient coolant. So much so that had
Huygens landed in liquid methane it would have ended
its operational life very quickly thereafter.

The crux of the issue is that Huygens' design is
fundamentally incompatable with long duration, or even
medium duration, surface science, let alone on Titan.
It needs not only greater longevity in general but
also different instruments and different overall design.
I think the inflatable wheeled rover / aerobot* is
probably the best design for this sort of thing available
at the moment. It would use 3 separate Helium filled
balloons as wheels in a rover. These would enable the
craft to operate as an aerobot during and after descent
(it could also take the place of parachutes), which would
permit it to perform extensive surveys of the atmosphere
and surface. Later the balloons can be partially
deflated to approach or touch down on the surface, for
higher resolution imagery or surface science. Finally,
while on the surface the Helium could be replaced with
ambient atmosphere, transforming the vehicle to an
amphibious rover. It looks to be an enormously capable
design, with quite a lot of potential.


(*) http://www.lpi.usra.edu/meetings/out...1/pdf/4023.pdf

http://www2.jpl.nasa.gov/adv_tech/rovers/summary.htm

Christopher M. Jones wrote:
I think the inflatable wheeled rover / aerobot* is
probably the best design for this sort of thing available
at the moment. It would use 3 separate Helium filled
balloons as wheels in a rover.
Yes, and they could have any amount of spare wheels waiting to
be inflated.

Lots of Greetings!
Volker

So what's Cassini going to do now? Just orbit Saturn forever? Keep sending
pictures?

"dexx" wrote in message
ups.com...
Is it true that Huygens ceased transmission less than 2 hours after
touchdown? Whilst it was a magnificent achievement to travel so far and
land perfectly, it seems a great shame that the probe was so short
lived. I'm suprised the designers didnt make it rugged enough and
powered enough to survive several days.

"Rodney Kelp" wrote in message
...
So what's Cassini going to do now? Just orbit Saturn forever? Keep sending
pictures?

I wonder if they realised Huygens would be such a
hard act to follow 7 years ago from the public's
point of view.

George

When they going to take a look at the surface of Saturn?

"dexx" wrote in message
ups.com...
Is it true that Huygens ceased transmission less than 2 hours after
touchdown? Whilst it was a magnificent achievement to travel so far and
land perfectly, it seems a great shame that the probe was so short
lived. I'm suprised the designers didnt make it rugged enough and
powered enough to survive several days.

"RK" == Rodney Kelp writes:

RK When they going to take a look at the surface of Saturn?

They aren't, and they can't. In all likelihood, Saturn does not have
a "surface." Rather, the atmosphere just keeps getting denser and
denser as you go deeper.

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"Rodney Kelp" writes:

So what's Cassini going to do now? Just orbit Saturn forever? Keep sending
pictures?

So, in a thread lamenting the fact that Huygens had to die so young, we
get a lament that Cassini isn't going to crawl off and die now that we
are tired of it.

NASA is wise in the ways of such matters, and will find an excuse as to
why the Glorious Cause of Science! requires that we crash Cassini into
something, or at least dive through a ring or a radiation belt or some
other suitably suicidal exploit. Probably about the time Cassini's
operations budget runs out.

You may have noticed that NASA has done this before, more than once.

And probably now wishes that they had designed Hubble with such an
ending in mind :-)


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"Rodney Kelp" writes:

When they going to take a look at the surface of Saturn?

If that wasn't a troll or a joke that went right over my head, the
answer is that Saturn doesn't have a surface. Just an atmosphere
of constantly increasing density and pressure, eventually blending
into a supercritical state of matter that does not recognize clear
distinctions between solid, gas, and liquid.


--
*John Schilling * "Anything worth doing, *
*Member:AIAA,NRA,ACLU,SAS,LP * is worth doing for money" *
*Chief Scientist & General Partner * -13th Rule of Acquisition *
*White Elephant Research, LLC * "There is no substitute *
* for success" *
*661-718-0955 or 661-275-6795 * -58th Rule of Acquisition *

John Schilling wrote:
"Rodney Kelp" writes:


When they going to take a look at the surface of Saturn?


If that wasn't a troll or a joke that went right over my head, the
answer is that Saturn doesn't have a surface. Just an atmosphere
of constantly increasing density and pressure, eventually blending
into a supercritical state of matter that does not recognize clear
distinctions between solid, gas, and liquid.



I am guessing by "surface" Rodney means cloud tops 60,270 km from
Saturn's center.

There've been lots of pics of Saturn's rings and moons but, come to
think of it, haven't seen many close-ups of Saturn.

In contrast, ISTR Galileo sending many spectacular photos of Jupiter's
"surface".

--
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http://clowder.net/hop/index.html