dexx wrote:
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.

I suspect you're going to be snowed under by responses to this, but...

Huygens was specifically designed as an *atmospheric* probe. It was supposed
to descend through the atmosphere, take readings, hit the surface and die.
Anything beyond that was gravy. They were hoping for ~30 minutes of surface
data; they reckon it was actually transmitting for about five hours.

The second point is that Huygens couldn't contact Earth directly. It had to
relay all its data through Cassini, and Cassini was due to drop below
Titan's horizon (that was the two hour figure). I believe --- can anyone
confirm this? --- that Cassini had to repoint its main antenna at Huygens
to pick up anything at all, which meant that it wasn't pointed at Earth,
which meant that it was completely out of touch, and since Cassini is a
hell of a lot more valuable than Huygens that's probably not a good idea.

The third point is that since noone knew anything about Titan's environment,
there was no way of designing a complex, long-duration lander that could
survive. The designers opted for a limited lifetime probe because that way
they could be sure of getting *some* data. The next probe will get more.

That said, I sympathise --- Huygens has returned just enough information to
let us know that Titan's really interesting without actually telling us
much about it. I wish Huygens had landed within sight of the coast! And I
do wish that it had been politically feasible to power Huygens with an RTG
instead of batteries; that would have been a simple way to increase the
lifetime without increasing the complexity (and reducing the reliability).

When's the next Titan mission due? Not for years and years and years, isn't
it?

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