"Glenn Mulno" wrote:

"richard schumacher" wrote:

I am a bit puzzled why they only made the probe last the few short
hours after it detached from cassini. They could of built a better
battery when Voyager I is like 28 year and still going. I know it is
like -300F and mechanical things won't operate long in that harsh
environment. Assuming the probe could survive the environment it would
of been nice to be able to tap it for everything possible.

The issue is how long the orbiter is in range to relay data from Huygens
to Earth. It's only a few hours, so a longer-life battery for Huygens
would have been pointless.

If that were the "only" reason then I would disagree. Cassini will be
passing by Titan again in a few weeks. I would think they could have held
data and then blasted it at the satellite each time it passed.

However, as I understand it that is not really why they kept the life to
only a few hours. I think it had more to do with just getting it down
safely, the weight of the probe on Cassini, cost, and probably just the
general expectation that conditions were not favorable to the life of the
unit being long.

The Voyagers and Cassini itself receive electrical power from a
Radioisotope Thermoelectric Generator (RTG). An RTG can provide
electrical power to a robust suite of spacecraft systems for 20 years or
more, but an RTG would have been way too heavy to install on the Huygens
spacecraft.

The Mars lander spacecrafts utilize solar cell panels to create
electrical power which is stored in rechargable batteries, and Mars has
very little cloud cover that would interfere with that system, and Mars'
night is similar in length to Earth's; so that system is workable on
Mars.

Titan has a dense, hazy atmosphere, and even in the clear, the Saturn
system is way too far from the Sun, making a solar power system to be
infeasible (the solar panel system would have to be gargantuan).

The Huygens spacecraft could not utilize an RTG or solar power, so it
was limited to un-rechargable batteries, and given the number of
instruments on board, battery capacity was limited to a matter of hours.

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