Cassini-Huygens Saturn Orbit Insertion Imminent 205
Anonymous Explorer writes "Fresh
off of its fly-by with the Saturnian satellite Phoebe, the
Cassini-Huygens
craft is set for Saturn
Orbit Insertion on June 30, 2004.
Cassini-Huygens has a planned four year mission ahead for Saturn
and its many moons. With 450 watts of power for the electronics, this
mission has plenty enough horses to run the stretch with plenty-o-pep
to spare. Thanks to all that power, and the plethora of electronics on Cassini
and the Huygens
probe, we
can now hear sounds from Saturn. Pretty cool stuff! Festivities are
scheduled to begin on June 29th with a broadcast of Cassini Saturn
Orbit Insertion Press Conference on Nasa TV. SOI [PDF link] will occur after Cassini
fires its main engine for 96 minutes, in order
to slow down and be grabbed by the pull of Saturn. As always we extend
an invitation to everyone to join
#cassini on irc.freenode.net and
help us celebrate this historic mission."
Not even 0.5kilowatts.. (Score:4, Interesting)
Victory of SCIENCE over ECOIDIOLOGY (Score:3, Interesting)
Lucky the officials at NASA and ESA weren't that stupid and fought off this attack.
The tremendous success of this mission illustrates how these 21th century idiologists are could stiffle science and cause harm for the whole world.
It makes me wonder if we could get this done today or in year with the eco rising to power in Europe and perhaps US after the elections, too.
I hope it takes photos (Score:3, Interesting)
BTW, how thick are the rings at the point where the probe is passing through them? How long will it take to clear that space?
Sound in space? (Score:2, Interesting)
Pheobe as a source of ice (Score:4, Interesting)
Re:450 watts? (Score:5, Interesting)
Only 20 Watts... (Score:4, Interesting)
Re:Ah, but did it generate the 450? (Score:3, Interesting)
Are you sure? That's pretty close to true on earth, where the cold side of a Carnot cycle is going to be at around 300 K. Space, however, is mostly a nice, big, cold blackbody at around 3 kelvin or so (cosmic microwave background.) That should help quite a bit.
On the other hand, other posters have noted that the mass calculation neglects the oxidizer that would have to be carried. That works out to being three or so times the mass of the fuel, depending on the specific hydrocarbons chosen.
I was an intern at JPL... (Score:5, Interesting)
Back then, the project was called "CRAF/Cassini" where CRAF was "Comet Rendezvous/Asteroid Flyby." CRAF was supposed to be the sister ship to Cassini, but it was cut for budgetary reasons. Too bad... with all the design work done how much could it have cost to just build another ship?
See, we were building this neat computer that would be reused on the next generation of probes, instead of having custom computer hardware for each... but of course it didn't work out that way.
I was lucky enough to see Cassini (and Galileo) in the Vehicle Assembly Facility. There was an observation deck where you could watch the guys in the clean room building the spacecraft. It was very cool to look down and realize, "that is going to Saturn." Or wherever.
Cassini is the last of the old school probe designs... a gigantic and expensive. She'll give us a heck of a show.
Actually, many Hams get by fine just a few watts (Score:4, Interesting)
"some HAMs are using 10 kilowatts upwards just for transmitting earth-to-earth!"
Actually, ignoring the 1.5KW max Ham radio ops are legally bound to, most Ham operators operate in the 100 watt range (in the HF freqs == "shortwave"), and there's a dedicated core of low-power enthusiasts who communicate around the world on 5 watts, 1 watt or even a few hundred milliwatts. (The microwatt crew even come out during favorable solar conditions).
Check out these guys [qrparci.org] for a starting point.
It varies by spectrum of course (VHF/HF/etc.) but I've personally worked every continent with less than 5 watts using just a homemade wire antenna, no fancy NSA-like array of metal high in the air.
Antarctica was the most fun - Russian op down there at their research station. Darn neatstuff!
Cassini's Real Interaction with the Rings (Score:4, Interesting)
Saturn right now is tilted, so that the south/"bottom" side of its rings is facing towards the Sun and Earth. Hence, Cassini is approaching Saturn from "underneath" as we see it from Earth. The orbit insertion requires Cassini to pass through the equatorial/ring plane south-to-north as it approaches the planet. It will fire its rocket while on the north side of the rings, and then coast back to the south side on its way back out.
Now, how is Cassini doing that safely? It's doing so by going through the ring plane where there are no rings. It could be thought of as a "gap", but Cassini really isn't anywhere near the rings when it crosses them. The crossing points are far outside the main mass of the ring system.
A rough analogy is this. Suppose you lived in Alaska, and had a sailboat named Cassini. Now suppose you had to sail from Alaska to Mexico without bumping into anything. Naturally, you'd pass between Hawaii and the continental US. That's a rough analogue to what's going on at Saturn - the main mass of the rings is like the continental US landmass (and there's a few small intra-ring gaps like the Mississippi River), while there's a few small outside rings sort of like the Hawaiian islands.
Would it be possible that your sailboat bumped into a rock or debris or something that we didn't know was there? Yes. Is that possibility remote enough that it makes for the safest course to your destination? Also yes.