(TFT) OT (?): Spacecraft Speed Records

[Mark Tapley <mtapley@swri.edu>]

At 19:02 -0400 9/27/11, Jay wrote:
> Still, she's a pretty little thing and a record holder for speed even before
> Jove. (but after drag from the Sun which I became aware of following her)
> Thanks for the info.

	Well, depends on how you count speed. It was the fastest ever 
leaving Earth, at roughly 23.74 km/s relative to Earth. 
(Astrodynamicists would say 157.75 km^2/s^2 excess specific energy.) 
Interestingly, the Messenger mission to Mercury was a close second! 
Both Voyagers and I think Pioneer 10 and 11 are departing the Solar 
system with more final velocity, having gotten better boosts from the 
giant planets.
	Jupiter's gravity is also responsible for what I think is the 
all-time record holder, Galileo, which made something like 59.5 
km/sec (relative to Jupiter) as it smacked into the cloud tops.
	"I don't care what inner-solar-system rocky planet you come 
from, that's *gotta* hurt!"
	In an astrodynamic sense, do not mess with Jupiter.

	In a world-building sense (back on topic?), if you are OK 
with major technological artifacts in your universe (Cidri?), a 
hyperbaric ecosystem floating around Jupiter's clouds would be 
interesting.

http://en.wikipedia.org/wiki/Atmosphere_of_Jupiter
http://en.wikipedia.org/wiki/Jupiter

	At the 1-atmosphere pressure level, temperature is still < 
200 K, so the "artifact" would be a huge (10's of km radius) bubble 
containing two chambers; an upper chamber of hydrogen, maintained at 
~300K by insulating layers trapping sunlight, and a "small" lower 
chamber of air, heated by the upper chamber and relying on the 
buoyancy of the upper chamber to stay aloft (basically a "hot 
hydrogen" balloon with the "world" in the "basket" of the balloon). 
Dirt, ponds, adventurers, etc. are all within the lower chamber.
	Power for water and methane condensers, etc. could come from 
thermocouples between inside and outside. Losing air or water could 
be replaced, but losing dirt would be a capital offense.
	Cloudscapes, seen outside through the transparent "bubble" 
walls, would be very very spectacular. Days would be ~13 hours long, 
but the sun is 25 times weaker (still enough to see just fine, but 
not much warmer). Surface gravity on Jupiter is about 2.5 Earth 
gravity, so people would break bones a lot when they tripped and 
fell, and running would be suicidal (and really strenuous). You could 
maybe see the Galilean satellites at night, but no way could you ever 
reach them.
	Storywise, I can think of several variants on Niven's "The 
Ringworld Engineers" that might be interesting. Or there's how the 
impact of Shoemaker-Levy 9, seen from reasonably close up, might 
affect the ecosystem. Or getting swept into the Great Red Spot - even 
more spectacular cloudscapes.
	The real upside is the graphic, final nature of the referee's 
answer to the player who says, "I dig".

--
						- Mark     210-379-4635
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Large Asteroids headed toward planets
inhabited by beings that don't have
technology adequate to stop them:

				Think of it as Evolution in Fast-Forward.
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