Cassini visits Earth 185
mwillis writes " Between 8:22 PM PDT and 8:51 PM PDT on August 17, Cassini swung by earth for a gravity assist, coming about 725 miles from the Earth's surface. It still needs a Jupiter flyby before reaching its target, Saturn. Video and mission status here " /sarcasm And, despite fears to the contrary, Cassini didn't smash into the planet and spread 75 pounds of Plutonium across the surface of the planet.
And where's yours? (Score:1)
Re:Babies with birth defects (Score:1)
2) How about powerful radio transmitters?
3) The Earth has a natural ground emission of approx. 1 milli-Sievert - do you intend to move to a less radioactive piece of rock?
Your reply is just techno-phobe insanity.
Re:Babies with birth defects (Score:1)
"The number of suckers born each minute doubles every 18 months."
-jafac's law
Re:But what's the benefit for science and humanity (Score:1)
I think for every probe that goes out and fails due to a programming glitch or defective anntenna, should be insured, and that insurance money should be paid to ME in the form a of a TAX REFUND. Same for expensive military contractors that run projects grossly overbudget and behind schedule. (Like THAAD, and F-22).
Otherwise, I'm all for sending chunks of plutonium into space. Park that sucker in my garage for all I care.
"The number of suckers born each minute doubles every 18 months."
-jafac's law
Re:Know the facts first (Score:1)
Meow!
Re:72 pounds? Try 4.5 TONS. (Score:1)
some decades now. We apparently survived, although how well is a matter of debate."
If you've ever looked at the curve of overall cancer rates around the world, how there was a steep climb in the 60's, 70's, it kind of levelled off in the 80's, and kind of declined in the 90's, perhaps there was a relationship there somewhere afterall. .
"The number of suckers born each minute doubles every 18 months."
-jafac's law
Re:that's very close! (Score:1)
Altering Cassini's trajectory to any significant degree would require an impact with a BIG piece of space junk. And those are the ones that are kept track of. Hitting a stray piece of junk might damage or destroy the probe, but unless it hits something with a lot of mass, the resulting debris will just continue on along the same path.
Re:If! (Score:1)
Unfortunately many (but not all) environmentalists seem to focus on the things that aren't significant even if things go wrong -- or they cause people to build coal power plants which will cause environmental damage instead of nuclear plants. I have seen claimed [www.dn.se] that the environmental movements are trying to block the safe storage of nuclear waste because it would remove one of the arguments against using nuclear power (this was in Sweden, in particular.)
Re:Of course, No-one bothered with Galilleo (Score:1)
Re:Babies with birth defects (Score:1)
Let your kids play in the basement very much? Even if you don't have a basement, I'm sure that you let doctors use X-rays on them.
Radiation is not something horrible thing evil mad scientists and the military industrial complex inflict upon the world. It's a fact of life. Mother Nature is loaded with the stuff. Take all the radiation in Cassini's RTG's and spread it out, you don't have to spread it very far to make it reach the same level as the natural background. If, however, you don't spread it out very far, then it's that much easier to contain and clean up.
What people are saying here isn't "techo-macho insanity". It's a realization that while everything has some risk, just because some microscopic risk is mentioned in the same breath as Horrible Evil Radiation isn't call to abandon all your rationality. People who don't know a Neutron from a Neutrino from their own Nuts are the most likely to get all worked up over such nothings.
Oh wait. I forgot. The reason that most all the people who actually know something about radiation and nuclear science aren't the ones who are freaking out is because we're all Evil Mad Scientists and part of the aforementioned Military Industrial Complex.
Fear of the Unknown. Had they lived 200 years ago, the same people who were picketing Cassini's launch would have been first in line to burn the neighborhood weird old lady as a witch when the village's cows got sick.
Alec
PS - don't forget to turn out the sun before you leave! Fusion! Oh the Humanity!
Re:If if if if if (Score:1)
Re: budget savaged to the tune of $1 billion (Score:1)
---
Re:If if if if if (Score:1)
I myself do not doubt the abilities of scientists and their system of differential equations which predict the path of the spacecraft, under the nearly-ideal conditions of space.
Here is what I have to mention: If this whole operation was really so completely safe that "nothing could possibly go wrong - and if it did, we could fix it", then why would NASA go to the trouble to manufacture the safety mechanisms? I mean, if there is a ZERO percent chance of re-entry, then why bother with the extensive protection of the plutonium for the condition of re-entry? To protect it from a malfunctioned lauch?? If this is a "SAFE" operation to launch plutonium, then I am assuming that the craft is -not- going to be exploding! The fact of the matter is, there was risk involved. No matter how small, it was enough to make these scientists take extra precautions. Furthermore, how can we really test those safety methods, short of recreating actual catastrophic explosions and re-entry conditions.
I don't see why it is necessary to put the lives of people at risk, no matter how small, for a largely trivial end. We have enough problems as it is, and encouraging people to make light of the work of scientists by not questioning their methods is only helping the blissful ignorance campaign of the Con. Hey-- plutonium in the sky is good! While we're at it, why not install Star Wars, and make the shuttle nuclear powered- now that we have conquored the solar system! And how would you like to sample some irradiated crops, while we unleash new untested strains of bacteria that wipe out entire species of "pesky" insects... so called "engineers" have been producing thousands of products for household use for decades that are now proven to cause insane cancer rates.
I love science and am a total techno-head, but I just don't see the point of indifferent behavior towards the people who objected strongly to Cassini. Even if this was the "viewpoint of an idiot who never learned newtonian physics", this attitude does nothing to help anyone.
Re:If! (Score:1)
That's always assuming, of course, that it got hot enough during re-entry to actually burn - it might just all melt together and fuse into one big, solid lump....
But "enough already", it didn't happen, and trust me (a Physics graduate) when I say that orbital mechanics is a well-enough understood branch of Physics that we can pretty much be completely sure of what we're doing.
(It's even simple enough to double-check the equations by hand on paper, if you mistrust computers that much)
Tim
Re: budget savaged to the tune of $1 billion (Score:1)
Re:Sociology Prof? (Score:1)
Unfortunatly, the Apollo program wasn't a scientific program, it was political. The only real goal was to put men on the moon before the Russian's did. It's only luck that we managed to get any scientific goals accomplished while doing it.
Re:Restoration of energy (Score:1)
that's very close! (Score:1)
first?
Re:that's very close! (Score:1)
Lots of worry from the yammerhead community over this one. Apparently, a liberal arts education doesn't include either physics or orbital mechanics in the curriculum.
Sorry, folks, but if it's at the right position in the sun's gravity well and moving at the right velocity, it's damn well gonna go along this orbit. Period, end statement.
Shmucks...
Re:Do you really believe a "safety report" from NA (Score:1)
NASA wrote the report because they did the engineering. Sheesh! Is everyone in the anti-Cassini / anti-RTG / anti-nuke crowd a conspiracy theorist? Or, worse, are they deliberately posturing that way to prime the real conspiracy nutbars?
They're lying, people! I mean, I want to promote space travel too, but don't be a sucker because they can count on all geeks blindly supporting NASA in everything they do. We are being used.
I strongly disagree with this. NASA does not have my uncritical support. I think the glory days are gone and the few good ideas left are mostly suppressed by the bureaucrats. Dan Goldin's much ballyhooed "Cheaper, Faster, Better" program is partly hype. Look at which programs were put on the chopping block when the budget was being cut. My hat is off the the folks at JPL and elsewhere who have to put up with NASA middle management for the chance to build a Mars Surveyor, NEAR, DS1, etc, every few years.
Despite all of this, when the science side of NASA, by some miracle, does manage to fool the PHBs and build a probe, and actually puts some decent engineering into it, I don't reflexively chop off their heads. I applaud them for it.
If you really "want to promote space travel" then you'd better lose your anti-nuclear attitude and instead support advanced propulsion systems. What we have right now isn't going to get humans out of the inner solar system. Some form of advanced propulsion will eventually be needed, be it fission, fusion, or even antimatter. If you build a working system from MagSails, solar sails, or tethers, I will applaud you. But, dang it, we need something that works.
In the meantime, read the other posts in this thread to see why worrying about a simple RTG is silly when the DoE has admitted that tons of Pu was released into the air by nuke testing, and when so many other radioisotope sources spew vastly more Curies of crap into the air unchecked. (Consider the U and Th content of fly-ash from unscrubbed coal power plants for a start.)
Then for an encore, learn enough Failure Analysis to be able to intelligently check NASA's impact report for substansive errors. If you find any, I'll listen to you.
Re:that's very close! (Score:1)
Challenger's O-rings. (Score:1)
Agreed (Score:1)
Re:Even if it disintegrates... (Score:1)
It seems that somebody has forgotten some basic physics. The deadliness of bubonic plague is based on its molecular structure; it would indeed be destroyed in descent.
The deadliness of plutonium, however, is based on its nuclear structure, which would not be affected by its descent in any way. It might be disintegrated, but it would still be plutonium.
clarification (Score:1)
Re:But what's the benefit for science and humanity (Score:1)
Having done that, further stretch your imagination to include the US Congress paying for a much bigger and heavier probe to Saturn. 8-)
Ironically enough, there was an another choice, but it was one that NASA rejected. Imagine the anti-nuke hysteria that would have happened if Cassini had been launched with an honest-to-God nuclear reactor, instead of just RTGs?
A fission reactor would actually be a bit safer than the RTGs, as it wouldn't need to be turned on until after the Earth fly-by. (But, RTGs are already so safe that the difference between 99.9999% and 99.99999% isn't very great.) Of course, outfitting Cassini with derivative of a SNAP reactor would mean that it would need solar cells for the E-V-E leg of the trajectory, and the reactor's emissions would probably blast the various particle instruments with spurious signals.
Probably the biggest turn-off to NASA was the lack of flight tested reactors. They wouldn't risk Cassini on a power source that hadn't been tested to run for decades.
So it comes down to solar power or RTGs, and solar just won't cut it out that far. Someday, maybe, when we have ultra lightweight and yet somehow more rigid concentrator cells. Don't hold your breath waiting for them.
Re:Agreed (Score:1)
Re:If if if if if (Score:1)
There's always risk involved in anything. There's a risk right now that a lighting strike will send a surge through the wires and electrocute you while you're using the computer. There's also a risk that a metorite will hit you while you watch tv. That doesn't mean that you will stop using the computer and live in a bunker does it? If the risk is small enough then most rational people will choose to disregard it as being essentially impossible.
I don't see why it is necessary to put the lives of people at risk, no matter how small, for a largely trivial end
What about the risk that an airplane will crash into a city or that a car driving down the street will suddenly swerve and hit people. I don't see why we use airplanes and cars just to get to other places quicker when there is that risk. I would argue that the ends that airplanes and cars are used for are more trivial than the ends that Cassini is being used for.
Re:Agreed (Score:1)
Re:72 pounds? Try 4.5 TONS. (Score:1)
Very interesting, if true. References, please. (And especially, references that take into account the anti-smoking campaigns in the USA during the - wait for it - 80s and 90s.)
Please also explain why there should be a plateau in the 80s, if the half-life of the short lived fision products are months, days, or less, and the long lived products have half-lives of thousands or millions of years.
(Bonus points for essays on common mistakes made in epidemiology, and why correlation does not necessarily imply causation.)
Re:that's very close! (Score:2)
The worst danger from this was if it somehow lost control, plunged into the atmosphere, and clonked you on the head.
Re:Sociology Prof? (Score:2)
They were reusable, achieved altitudes that were pretty close to the Mercury capsule altitudes and could land on the groud and be reused. Had the program continued they probably would have built a plane that could achieve LEO sometime in the 60's.
I don't mind using big rockets for heavy lifting, but I have always preferred the idea of establishing a space station in Earth orbit from which both small ferries to Earth and missions to the Moon (and other heavenly objects) could be launched. Von Braun also pushed for that idea, but as long as he was building big ass rockets anyway the Lunar Orbit Rendevous plan killed any chance for a permanent space station.
The International station and Mir are pipsqueaks comapred to Skylab, which rode up on one Saturn V and would still be operational today had they not put it in too low of an orbit. The thing was as big as a house.
Had things worked out differently, I think that we could have wound up with a fleet of LEO-capable space planes, a wicked huge space station and a large, permanent (or semi-permanent) base on the moon.
It's true though, that a lot of the Apollo program decisions were motivated by the political need to get to the moon by 1970 at the latest. And the rush to get there meant that no infrastructure was left to permit the space program to grow. It was a one time goal that accomplished very little in the end.
Conservation of energy (Score:2)
Somebody should start a campaign to prevent NASA from using Earth for gravity assists. Our lives may depend on it!
For the humor impaired
Re:Babies with birth defects (Score:1)
There is an earthquake, which knocks down the support building, leaving the access door exposed, then an F5 tornado comes along, and picks up a telephone pole, and wings it, small end first at the door. Impact is at 300mph. The door has to hold. (I was there for the test, it held - Yes, we fired a telephone pole at the door (a sample door))
Cassini's RTG was designed to hold together through either through a launch explosion, or a worst case re-entry
Re: budget savaged to the tune of $1 billion (Score:1)
"Cake or death!" (E. Izzard)
Re:Nuclear Whining - The New Olympic Sport (Score:1)
It just stuns me to see people resort to simple-minded name calling over this issue. This RTG issue has been beaten to death, and this unnecessary hysteria has to stop. Give me counterexamples, not insults. You cretins can all go back to your creationism classes now.
}\\flame
Re:Babies with birth defects (Score:1)
This is not a joke. See
http://www.bnfl.co.uk/
I guess they should know whether it's dangerous or not. They're the ones who have to work there.
"Cake or death!" (E. Izzard)
Re:Babies with birth defects (Score:1)
Re:wouldn't want to question "progress"... (Score:1)
This is bogus. See the other posts in the thread for reasons why. (I.e. If 72 pounds of plutonium dioxide can do us in, then why are we alive after tons of Pu-238 were blasted into the air by above ground nuke testing.)
If we let ourselves get used to cheap, brute force crutches like plutonium fueled vehicles, we get stuck with them - they become the standard, not the bonus.
Let's clarify this -- the rocket that launched Cassini was a chemically powered vehicle. The probe itself is equipped with chemical rockets, both for the main engine and the thrusters. Pu is not Cassini's "fuel." It is its power and (to a slight extent) heat source.
Better?
Nothing makes people like that feel more secure about themselves then to believe the great machine that they're a happy little cog in runs as well as everybody promised; that real life does work exactly like the sample problems in their textbooks; that there is never any need to step back and wonder what life might look like if a few "truths" were less than true.
Did you have any specific untrue "truths" in mind? Conservation of Mass-Energy? Newtonian mechanics? (Which are being used to calculate Cassini's trajectory.)
Anyway, I take the contrary view. Before Cassini's launch I saw more news airtime given to the anti-Cassini crowd than the pro-C side. I suppose that graying scientists were a lot less dramatic than oddballs with bad haircuts carrying signs and chanting "No Nukes!" IMNSHO the "cogs in the machine" are the ones who bought the media fear-mongering.
I agree that we should have a better propulsion source, but will not halt all exploration until one is devised. After all, how many new propulsion systems have been brought on-line in the past 30 years? Is there even one? (You can't count DS1's ion engine. They've been around since the 60s. The only innovation is political -- to let the engineers finally install an ion drive as the main engine of a probe.)
Sure, upgraded series of rockets come out, but they differ only in detail from the rockets of the 60s. And, the cost to launch a pound of payload into low orbit hasn't dropped below $3000. There's something wrong here.
Assuming you live in the USA, have you written your congresscritter to support NASA's "Future X" program?
Re:If! (Score:1)
many times to infiltrate the power plant there,
in an attempt to *cause* an accident! They even
tried to bring down a power line tower!
OOps boss is around corner gatta go!
Re:72 pounds? Try 4.5 TONS. (Score:1)
Antibiotics, vaccines and clean water cause cancer rates to increase. In the "good old days", most people died before they were old enough to develop cancer.
Re:BIG RISK:Cassini carries a HUGE load of Plutoni (Score:1)
The thing that pulls the rug out of the arguments is that RTGs have been in craft that have exploded at launch and burned up on reentry. Every RTG in those craft landed intact (although not all were recovered) I believe one was tracked into the ocean where it couldn't be recovered.
Does that eliminate all risk? Of course not, but combining the risk of the RTG actually disintegrating with the probability of the craft actually hitting the earth with the actual damage the dispersed plutonium might do, and the risks are extremely small. Oh and the risks at launch are even smaller, since even if every fuel source on every booster were to explode simultaneously with every molecule of fuel combining with with an oxidizer at the same instant (a complete impossibility) the resulting forces would at worse launch the intact RTGs away from the launch sight, but could not possibily disintegrate them.
Re:wouldn't want to question "progress"... (Score:1)
ummm... i didn't think we were done counting the casualties from nuke testing yet. seems to me that plenty of people are still suffering and dying from it, not that it's being publicly acknowledged. (and, frankly, i just don't get the mentality that it's ok to do a little more of a bad thing we've done a lot of in the past; not exactly what i'd call social evolution.)
Let's clarify this -- the rocket that launched Cassini was a chemically powered vehicle. The probe itself is equipped with chemical rockets, both for the main engine and the thrusters. Pu is not Cassini's "fuel." It is its power and (to a slight extent) heat source.
Better?
Damn well better NOT be nuclear powered rockets within our atmosphere. My bad, though, shouldn't have started talking about propulsion, when I just meant power source in general.
Did you have any specific untrue "truths" in mind? Conservation of Mass-Energy? Newtonian mechanics? (Which are being used to calculate Cassini's trajectory.)
This is exactly my point. All you're thinking about is your textbook problems. Think REAL WORLD. Want some specific "truths" ?
How about things like real statistics on the amount of debris in orbit over the earth, and the accuracy to which the trajectories of every piece are truly modelled. Also, everyone seems so quick to believe the government when the government promises the casing is "explosion proof." How many times are we going to have to hear, "Well, uh, in the tests everything SEEMED fine..." Between the government's history of misinformation and the fact that testing doesn't guarantee jack, I'm sorry if I'm a little skeptical about what I'm feed as truth.
I agree that we should have a better propulsion source, but will not halt all exploration until one is devised. After all, how many new propulsion systems have been brought on-line in the past 30 years?
Sorry, but them's the breaks. I just can't condone strapping a bunch of highly toxic material to a rocket that has, what, about a 1 in 6 failure rate? Please don't tell me that it's OK because only a small part of Florida, or the Pacific Ocean, or whatever would get poisoned in the event of a disaster. No one has any right to make that sacrifice.
Assuming you live in the USA, have you written your congresscritter to support NASA's "Future X" program?
No, thanks for the tip. The truth is, I'm not exactly an activist here, just been playing devil's advocate for the sake of discussion. I will look into this, though.
Re:72 pounds? Try 4.5 TONS. (Score:1)
"The number of suckers born each minute doubles every 18 months."
-jafac's law
Re:BIG RISK:Cassini carries a HUGE load of Plutoni (Score:1)
You really had me going until this part
Re:that's very close! (Score:1)
Make no mistake, Carl Sagan himself was torn between advovating plutonium and opposing it, though he came on the side of advocating it.
Re:I doubt it (Score:1)
I doubt it (Score:1)
Lets suppose for a moment that 75 pounds of plutonium *did* come hurtling through our atmosphere. First and foremost, it would probably be so badly degraded upon re-entry that it
wouldnt matter *what* it was. You could send a damn dump truck full of boubonic plague through the Earth's atmosphere, it would probably disintegrate before ever reaching the
ground. The earth is continually bombarbed by fairly large chucks of threatening debris 24 hours a day, 7 days a week, 365 days a year. Its been this way for millions, if not billions of
years. There's a _reason_ why we arent living in a sea of craters, kids.
you are talking about molecular breakdown; plutonium is an atomic particle. The heat from a nuclear explosion does not alter an atom's radioactive property so a reentry is gonna do zit. You're a looking a 75 pounds of radiactive dust spreading all over the atmosphere. Not a pretty picture.
Hasdi
Re:Babies with birth defects (Score:1)
Well said!
Frankly I think it must be a troll, it does that "thing" to my blood pressure, y'know, where I just wanna SCREAAAM and hit the roof...
It's also over-emotionalist claptrap
~Tim
--
Re:that's very close! (Score:1)
clonked you on the head.
ROTFL! Thanks for brightening up my day
~Tim
--
Re:Babies with birth defects (Score:1)
The researcher who did this study faked his data. There is no link. This was big news a month or so ago.
Now... (Score:1)
That's my 1/50 of $1.00 US
JM
Big Brother is watching, vote Libertarian!!
But what's the benefit for science and humanity? (Score:1)
First of all, it is true that the worst case scenario that is painted by even the most fervent opponents of the mission is rather mild compared to other dangers that are facing us all the time. Still, I wonder why people feel the need to ridiculously downplay the dangers of plutonium. Who cares if it is really ``the most deadly substance'' - the stuff is nasty enough to cause a big headache for any organization charged with handling it responsibly.
However, the real issue is what are the benefits for us (as human beings in general) that justify putting money in the billion dollar range? Since very few people have a true interest in the advance of astronomy as a basic science, the real reason for putting so much effort in these missions are the technological spin-offs that may result. If you see it from this point of view, the Cassini mission becomes really scary!
- One ``dream'' application is the further militarization of space. Plutonium battery powered spacecraft could be smaller, less vulnerable, and less restricted in their orbits than solar or conventional fuel powered ones. Should anyone want this? - Definitely not!
- The development of civilian plutonium-based space missions helps to support a nuclear industry based on the plutonium cycle. The only people who really benefit from the plutonium cycle is the military (and I don't really think of the United States so much as they have enough nuclear bombs to blow us all up anyway). For civilian use it is a complete folly (economically as well as environmentally: The by far the worst radioactive polluters are reprocessing plants (plutonium extraction!), not from nuclear power stations).
- One the other hand, the rejection of a solar power source for Cassini meant what could have been a major push for solar power technology did not happen.
I am not making this statement as a blind advocate of solar power. But I do notice that a choice was made to spend a lot of money, officially on a basic science mission, in such a way that indirect benefits go to the military, and not to sustainable civilian uses.In short, it leads us away from responsible use of nuclear power, which I believe is possible.
Marcel (oliver@member.ams.nospam.org)
Re:that's very close! (Score:1)
Re:wouldn't want to question "progress"... (Score:1)
You've missed my point. Did you read the other posts on the "Pu is the world's most toxic substance" urban myth? The very fact that you and I are alive refutes that legend. And, since that seems to be the lynch-pin of your argument, it casts doubt on the rest.
Also, along the "didn't think we're done counting casualties from nuke testing yet" line, how do you separate cancers from N tests versus cancers caused by smoking, food-borne carcinogens, radon seeping up from the basement, or whatever, at this late date? Epidemiology is tricky....
In fact, I wouldn't be surprised to learn that it is dern near impossible to trace the genesis of any specific cancer more than a decade or two from the suspected exposure. (At least, not outside of the lab, which you seem to scorn as the home of unrealistic fiends who want to force-feed you Pu-239. 8-)
. . . . Want some specific "truths" ? How about things like real statistics on the amount of debris in orbit over the earth, and the accuracy to which the trajectories of every piece are truly modelled. . . . .
Ah, now you're getting down to brass tacks, instead of throwing around glittering generalities. But, none of the complaints above invalidate anything you'd learn in Physics 101. They're all textbook examples of ballistics. Horrors! ;-)
For what its worth, Space Command (or whatever agency lives under Cheyenne Mountain) tracks the trajectories of all that space junk. NASA routinely clears its orbits with them. "To what degree of accuracy?" Beats me; it's a national security secret.
But, it doesn't matter. The big stuff (say 6" across or more) is tracked by the large Schmidt cameras in Hawaii and various other locations around the world. Their orbits are known to within some classified, but small, amount of error. Anything smaller can't shift the probe's path enough to matter. Sure, one little paint chip could destroy a major subsystem, but that won't alter Cassini's orbit by even 1%. (Think conservation of momentum, another of those useless, totally divorced from the Real World, textbook concepts.)
And again, your alarm at even an infinitesimal possibility of a reentry seems to be based on an exaggerated view on the carcinogenic properties of PuO2 dispersed over some remote part of the world. This I dispute because it already happened and we didn't die. That's not a textbook problem; it's Real Life(TM) data.
In 1964, SNAP-??, installed in a military navsat, reentered the atmosphere. The RTG as designed incinerated the metallic Pu within. (This was a stupid design decision. If you want to gripe about any RTG, this is the one.)
As a result, future RTGs were designed to survive reentry. In 1968 and 1970, they did just that, in a weather satellite and Apollo 13's LEM, respectively. The weathersat RTGs were recovered, refurbished, and reused. The Apollo 13 RTGs were targeted at a deep ocean trench off of Fiji. No signs of leakage were ever discovered.
You might say, "They never really looked." Maybe they did, maybe they didn't. Either way, you're the one claiming world-shaking consequences to a RTG reentry. These happened, yet the searing waves of deadly radiation didn't scorch the life from the planet, or even the Pacific, and we're all here to tell the tale.
How many times are we going to have to hear, "Well, uh, in the tests everything SEEMED fine..." Between the government's history of misinformation and the fact that testing doesn't guarantee jack, I'm sorry if I'm a little skeptical about what I'm feed as truth.
Don't apologize, it is good to be skeptical. Doubt the government; doubt everything I write. Check and double check all assumptions and unstated conditions. Go back to the primary sources and check again.
On the other hand, don't go overboard and descend into paranoia. If the engineers really had kludged the heat shielding on the RTGs, or fudged the risk assessment on the chances of a launch explosion, why were so many of them -- and their families -- present at the launch? Wouldn't simple self-preservation send them into their cellars or on long vacations to the Yukon? 8-)
Is it not possible that they really did do a good job of protecting the RTGs and were proud enough of their work to be present at the launch?
Let me ask you this: Do you think it is even possible to build a RTG that will stand up to a launch accident?
If you don't, just say so. Nothing I write will be able to allay your fears, and we might better use the time elsewhere.
Sorry, but them's the breaks. I just can't condone strapping a bunch of highly toxic material to a rocket that has, what, about a 1 in 6 failure rate?
Again, you imply a vastly greater risk to this event that the evidence supports.
Hmmm.... That 1 in 6 claim sounds familiar. Have you been alarmed by one of those anti-Cassini web sites, the ones that can't tell the difference between a space probe and a H-bomb? If so, take every claim they make with an entire shaker of salt. More than that, is there some specific claim they've made that you would like to discuss?
Re:72 pounds? Try 4.5 TONS. (Score:1)
- You didn't provide any references.
- You didn't justify the claimed change in cancer rates. In fact, if the Pu took 30-40 years to settle out, wouldn't we just be starting to see an increase in cancer?
- Most importantly, you didn't comment on the effects of the anti-smoking campaigns, which started bearing fruit around the time that the claimed cancer rates started dropping.
Anyway, the evidence on dust is against you. Remember Mount Pinatubo(sp?), the volcano that blew up violently in the Phillipeans about ten years ago? It injected a large amount of sulfuric acid aerosols into the stratosphere. The aerosols took only 2 to 3 years to settle down into the troposphere, where rain could wash them out. I remember this clearly, because as an amateur astronomer, I complained about the high haze caused by that acid mist, until it finally cleared. 8-)Re:Know the facts first (Score:1)
"Cake or death!" (E. Izzard)
Re:Babies with birth defects (Score:1)
Go to http://www.bnfl.co.uk/index1.html
Go to Activities -> Transport then click on "Film: Locomotive"
Enjoy
"Cake or death!" (E. Izzard)
Re:plutonium isn't THAT toxic (Score:1)
Re:plutonium isn't THAT toxic (Score:1)
Re:If if if if if (Score:2)
The only time there was even a minutely significant chance of the probe re-entering the atmosphere was shortly after launch. The safeties were likely designed for that eventuality, not for the fly-by.
this is a "SAFE" operation to launch plutonium, then I am assuming that the craft is -not- going to be exploding!
There's no such thing as a 100% "SAFE" launch. There's always the possibility that the launch vehicle will explode on the pad, or shortly after lift-off, or perhaps later, when the probe is reaching earth orbit. Do you honestly think that such an explosion will cause a horrible radioactive dust cloud to settle down over half of the United States, killing thousands and giving cancer to countless millions? Not going to happen.
encouraging people to make light of the work of scientists by not questioning their methods is only helping the blissful ignorance campaign of the Con.
Who is encouraging this? This goes against the very foundations of science. By all means, question. But don't question US, question THEM. Read the press releases THEY'VE written, because those are the answers you're looking for, and you won't always find them here (though quite a lot of Slashdot regulars are qualified to respond).
Some people are indifferent to Cassini due to ignorance, I'll admit, but lots of us are indifferent to Cassini because we KNOW BETTER. You'll discover most all truely qualified astrophysicists and scientists were all TOTALLY comfortable with having Cassini make its pass. While they had to admit there was a slim chance of a collision (as they had to, since there's always a slim chance), that chance was somewhere in the neighborhood of 1 in several million, and getting more remote the closer Cassini came to earth.
If all of the people qualified to make decisions about something seem content that things are OK, perhaps you should give them the benefit of the doubt. NASA engineers are not stupid people. Ask your questions, sure, but don't turn a blind eye to the answers because of your own fears and doubts.
Re:Do you really believe a "safety report" from NA (Score:2)
Wow, you're ABSOLUTELY RIGHT. Why in the world did I ever put my trust in space flight with the DOZENS of experienced men holding PhD's in things like astrophysics and engineering when I can run around screaming with my arms up in the air with the rest of you uneducated Slashdot kiddies?
NASA isn't some sort of covert government agency bent on getting things into space no matter what the cost. The guys at NASA aren't stupid. Give the people with degrees the benefit of the doubt and leave your conspiracy theories at home.
Dr. Evil in Congress (Score:1)
The Divine Creatrix in a Mortal Shell that stays Crunchy in Milk
Re:But what's the benefit for science and humanity (Score:1)
Bzzt, sorry, thank you for playing. NASA *wants* to use solar power. Solar power is cheap, easy and comes with no political headaches.
But, at Saturn, the solar flux is 1/90th that of earth's. AND-Cassini needs to broadcast data much farther than your typical geosat. If Cassini used the most efficient solar panels know at launch time (which, of course, is impossible, since it takes at least a couple of years to build/test a probe, it would have been much heavier-and thus, it couldn't be launched with the boosters then in use.
I am not making this statement as a blind advocate of solar power. But I do notice that a choice was made to spend a lot of money, officially on a basic science mission, in such a way that indirect benefits go to the military, and not to sustainable civilian uses.
No, money was spent on the only power source, know to man, that would be able to drive several instruments, record data, and transmit that data from the orbit of saturn. Furthermore, Pioneer 10 and Voyagers I and II are all RTG powered, and are still scientifically useful.
This isn't a nuclear/non nuclear or civilian/military question. This is a simple engineering exercise.
The ONLY power source capable of running the insturments aboard, and transmitting back that data, from a jovain orbit or farther, while still remaining light enough to be lauchable, is an RTG. Therefore, an RTG was used.
Re:plutonium isn't THAT toxic (Score:1)
--neil
Re:and even if it did crash... (Score:1)
Do you know what an ion is?
I'm smart enough to know what you actually meant with your above comment. It scares the hell out of me that you're not smart enough to say what you actually mean.
Re:that's very close! (Score:1)
--neil
Re:Babies with birth defects (Score:1)
I'd rather risk my life by a scientific mishap than have things stay at status quo. If this civilization is to survive we *need* progress in physics and space exploration. We are not getting any, all money goes to stort-sighted business ventures. And then people object to even that little that IS being done. People like that will be the first to get a weapon and go on killing and looting if a world collapses in a few decades due to lack of energy or whatever. The same people who believe only *they* have any rights. People who tell you what color to use on your house, what plants to plant, and that no nudity is to be seen in theatres. Or don't give a shit about their economies exploiting other nations or even killing people just to keep their industries going.
I'd take scientific risk over human risk any time. I'm sick of people's "righteousness".
Re:We'll always have Titan (Score:2)
However, given that the Pu is encased in an extremely durable salt/ceramic mix, it's not nearly so dangerous as a hunk of raw Pu would be.
Re:Babies with birth defects (Score:1)
Re:Never trust a hippy. (Score:1)
You are off by several orders of magnitude. The bare sphere critical mass of Pu-239 is about 10 kg.
There is about 5000 kg of Pu-239 in the environment as a result of fallout from nuclear testing.
RTGs use Pu-238, a plutonium isotope that is about 250x more active than Pu-239.
Re:Sociology Prof? (Score:2)
I did very poorly in that class, primarily IMHO because I disagreed with him all the time, and on a number of occassions pointed out that he was provably wrong on something, and corrected him. It's all in the past now, so I don't really care much anymore, but he certainly made me realize that a lot of crap that I had tacitly supported or accepted was in fact, crap. That's good anyway.
Now, while I like the Cassini mission, and I'm willing to defend it from people with a science background of 'Plutonium is pure evil,' I don't really like NASA all that much.
I would have preferred that the USAF had been given more opportunities to research spaceflight. Between Von Braun's ultimately stupid utter reliance on rocketry and NASA's unwillingness to conduct the Apollo mission gradually (with a permanent Skylab-type installation in the mid-60's) we're really not at all as far ahead in space as we should be. About the only good thing there is regarding NASA, IMHO is that they are basically a civilian agency. It would have been crappy to let the military dominate space, but I could accept joint programs.
Couldn't have said it better myself (Score:2)
Please read before you post (Score:2)
The CERAMIC plutonium was divided up into small pieces encased in, I believe, uranium and graphite (or something), among other things. The idea is that, even if the probe were to have exploded or impacted the earth, the chunks of plutonium would not have burned up and neither would they have been in any way exposed in the end.
The chances of the Plutonium "catching fire and dispersing in the atmosphere" are nearly non-existant. Please do a little bit of research before you make assumptions like this and make AC's look worse than they already do.
72lbs of Plutonium isn't a lot.
You may think all scientists are arrogant, uncritical and blissfully ignorant when it comes to the things they do, but you should be willing to concede the possibility that the people with the PhD degrees in things like astrophysics and nuclear engineering might just know what they're doing. Mistakes happen, sure, but these guys are not stupid.
Re:Emotionalism and Information flow versus Scienc (Score:2)
Why in the world did you post this as an AC? Post it as a user and be known. Let the credit flow to you. Let your comment's score be greater than zero.
Re:Titanic IV's (Score:2)
A:
"Since we're some kind of evil government agency, it's high time we started acting like one. We have all of this spare nuclear fuel around, let's see if we can trick congress out of some more money so we can build even MORE expensive space probes that can use some of this nuclear fuel. Oh, and don't bother trying to make it 'safe' or anything. We'll just tell everyone that we've got it safely in hand and there's no chance of any problems. Hah!"
B:
"OK, which energy source is going to work for us in this case? Solar? Let's see.. Hmm.. at this distance from the sun, we'll need X amount of power for the instruments.. which means we'd need solar panels that big.. hmm.. that's going to be expensive and heavy. Is there another power source that we can use that'll be lighter and more efficient for us? Ahh, that will work nicely."
C:
"OK, we have plans for the new probes all using solar panels, but you know, damn, we just have all of this extra money lying around. Let's outfit all of these babies with some NUCLEAR power! Yah, man!"
Concede the possibility that the men in white coats with PhD's in things like astrophysics and nuclear energy MIGHT just know what they're doing, whereas you do not.
Re:Sociology Prof? (Score:1)
Re:wouldn't want to question "progress"... (Score:1)
I think I'll just drop this. We're orders of magnitude apart insofar what we see as good science and engineering. To you good engineering is taking a risky endeavor and decreasing the risk as much as possible (an evolutionary approach.) To me good engineering seeks novel, risk free solutions (a revolutionary approach,) and is willing to be patient until the good solutions come.
As an example, rather than using plutonium to power Cassini's instruments, why not a flywheel based generator? There have been great advances in flywheel technology lately. In low-G and free fall environments, friction isn't a worry, so you'd get pretty decent efficiency. You ought to be able to torque the flywheel back up by catching a little angular momentum during a grav assist, if you make the approach just right.
It scares me to death to hear someone as apparently educated as you (and the others like you on this site) have no concept of long term ecological responsibility. It's enough for you that "you and I are alive right now," so therefore airborne dispersal of granulated heavy metals and radioactive material have no effect. DDT didn't get banned because humans started dropping off like flys in its presence. Lots and lots of major ecological damage was done before anyone started to do anything about it.
It's not about being a hippie or a luddite, it's just about acknowledging that the current dominant paradigm (to use a scary soc. word) of technological advancement has brought us some pretty dark returns. It's time to start learning from history. If we, as scientists (believe it or not, I am, in fact, a physicist - granted I'm a theorist) want to improve the reputation of scientific advancement, we have to start opening our eyes to the real world outside of the lab. Any risk is too much risk when it comes to endangering what little remains of the global ecosystem.
Re:wouldn't want to question "progress"... (Score:1)
Life is a risk. You take your life in your hands every time you drive to work. (If you bike, take the bus, or walk you take even bigger risks.) A gasoline truck drove by your workplace today. It had a small, but non-zero risk of intense fire or explosion. Pesticides, herbicides, and serious industrial chemicals are shipped by truck and rail every day. There are risks associated with all of this.
"The cowards never started and the weaklings died along the way." (Please direct all Politically Correct flames to the nearest propane tank. ;-) There's dern little risk-free anything in this life. Get used to it. Work with it. Make it work for you. . . . If you just "wait" for revolutionary advances to come to you, they'll never happen. Somebody has to make them happen. Somebody willing to try something new, and possibly a bit dangerous.
And yes, I'm still going to minimize those risks to the extent possible and practical, even if you don't find that esthetically pleasing.
As an example, rather than using plutonium to power Cassini's instruments, why not a flywheel based generator? There have been great advances in flywheel technology lately. In low-G and free fall environments, friction isn't a worry, so you'd get pretty decent efficiency. You ought to be able to torque the flywheel back up by catching a little angular momentum during a grav assist, if you make the approach just right.
Ingenious, but there are a few problems:
- Flywheels don't generate power. They just store energy. On a mission that will last 11 years or more, a reliable, long term source of power is needed.
- Cassini's last gravity assist is at Jupiter. It won't reach Saturn until years later. What provides minimal housekeeping power (and heat) for that time?
- Off hand, I really doubt you can pick up any significant power without a much steeper gravity gradient than either Jupiter or Saturn has (to say nothing of Earth). I suspect it would take a close approach to a neutron star or a black hole to spin up your flywheel. (And no, I'm not going to pull out MTW's Gravitation and try to remember enough calculus to use it without serious consulting money. 8-)
You'd do better to look into electrodynamic tethers. In the presence of a strong planetary magnetic field, they can turn an orbiter's kinetic energy into electricity and vice versa.Cool? Yes. Ready to use in the outer Solar System? Definitely not.
We've had trouble making tethers work in the two Space Shuttle missions that tried them. The SEDS folks have had better luck with their regular and electrodynamic tethers, possibly because they started small and built up. Besides, the conditions dictated by the Cassini mission wouldn't be right for an ED tether.
It scares me to death to hear someone as apparently educated as you (and the others like you on this site) have no concept of long term ecological responsibility. It's enough for you that "you and I are alive right now," so therefore airborne dispersal of granulated heavy metals and radioactive material have no effect. DDT didn't get banned because humans started dropping off like flys in its presence. Lots and lots of major ecological damage was done before anyone started to do anything about it.
You're still missing my point: The claims that "Pu is the most toxic substance in the world" are bogus, wrong, and incorrect. If those claims were true, we should have been dead many times over. The DoE admits to something like 4.5 tons of Pu-239 was released by USA nuclear bomb testing. That's only the Pu. How about the radio-activated bomb casings, dirt, and other debris? How about the U-235? How about the vastly more deadly fission products? What about the Soviet and French bomb tests? Even more radio-crap kicked into the stratosphere.
When I say "we're still alive" that's an existence proof that the claims of the anti-Cassini groups are flat out wrong. It is not an invitation to dance about the world scattering PuO2 around. Sheesh!
Tell you what -- let's consider Teller's bet. If you still believe that Plutonium is the most lethal substance on Earth, then I'll swallow 1 milligram of Ir-coated Pu-238 dioxide, if you first swallow 1 milligram of botulism toxin. Then we'll see which is the most poisonous stuff around. You'll die in frothing agony within minutes while I might get cancer 20 years from now. Maybe. (Even that is unlikely thanks to the iridium coating -- but since Cassini is using Ir, so can I. 8-)
Furthermore, Cassini wasn't going to crash and didn't crash. If it had, I was willing to bet that the RTG designers had done their job right. (Didn't you watch the tapes of the RTG testing?) Even if they hadn't, we're back to the "deadly Pu" myth again.
You're "scared" that I and others aren't "ecologically responsible" enough to suit you. Well, sorry. I'm not going to stop thinking about life's risks and start emoting about them (i.e. become a neo-Luddite). And, I can't help your fears, other than to point out where they are unfounded and to hope that you will conquer them.
It's not about being a hippie or a luddite, it's just about acknowledging that the current dominant paradigm (to use a scary soc. word) of technological advancement has brought us some pretty dark returns. It's time to start learning from history. If we, as scientists (believe it or not, I am, in fact, a physicist - granted I'm a theorist) want to improve the reputation of scientific advancement, we have to start opening our eyes to the real world outside of the lab. Any risk is too much risk when it comes to endangering what little remains of the global ecosystem.
Well, hell. If you're a theoretical physicist, then you can break out Misner, Thorne, and Wheeler to find out how feasible your flywheel idea is. Remember that you're limited to, at most, one metric ton. (Even that is generous; the RTGs don't weigh that much.) And, you've got to fit the resulting flywheel and it's housing into the Shuttle's cargo bay. Oh, and make sure that this enormous spinning flywheel doesn't make it impossible to maneuver the probe. C'mon -- I dares ya! I double dares ya! ;-)
Also, get off your philosophical high horse. Species have been made extinct with nothing more than sticks and stones. (E.g. the hypothesized extinction of the America's large mammals (mammoth, etc) by human hunting after the last Ice Age, and definitely the Dodo, killed by sailors armed with clubs.) Consider human misery caused by the Khmer Rouge with relatively little technology and a whole lot of savagery.
In other words, science isn't the problem; it's what you do with it. There's no tool in existence that can't be used for good or for evil. Any increase in power comes with an increase in responsibility. All your talk about "dark returns" and "want to improve the reputation of scientific achievement" strikes me as a bit too Woody Allen-esque for my tastes.
"Any risk is too much risk ...." Feldgercarb! If you truly believe that, then you'd better go out and commit suicide, because your very existence is a slight risk to the global ecosystem. (Sure, it's an incredibly slight risk, but you're the one claiming "any risk is too much".) Remember the the Oklo natural nuclear reactor? It fired up in Africa (references not at hand) a long time ago, and operated sporadically for millions of years. No containment dome. No nothing -- just an unusually rich bed of uranium ore moderated by the soil and ground water. The planet survived that. It will survive us.
That's not to say that we can strew our garbage wherever we like. The ancient proverb, "Do not throw rocks in the well you drink from" still applies. But, the whole point about intelligent life is that it makes new resources and new ecological niches possible. If our species has a "purpose," then it may well be to bring life to lifeless planets. It is not to hide in the basement because we're afraid to do anything at all.
Re:More Niven-Pournelle BS (Score:1)
Re:Beowolf (Score:1)
Doug
Re:Beowolf (Score:2)
>Or better, a cluster made of people
A Soylent Green cluster?
this thread reminds me of a story I read (Score:1)
the author was one of the scientists working on nuclear power. he was employed by General Atomics. (strangely enough, an ex-division
the reason for the choice was political rather than scientific/technical. (the scientists were all for the safer reactor)
can anyone confirm this or do I have to go have another drink?
72 pounds? Try 4.5 TONS. (Score:1)
That means that some 9,000 pounds of metallic plutonium has been circulating in our atmosphere for some decades now. We apparently survived, although how well is a matter of debate.
The 72 pounds of ceramic plutonium on board Cassini is a pittance in comparison and is chemically much harder to incorporate into the body than the metallic form.
Let's put it this way. If I ate a teaspoon of what Cassini is carrying, I'd stand a slightly elevated chance of colon cancer some twenty years down the line. If, at the same time, you ate a teaspoon of a completely legal substance, nicotine, you'd be dead in minutes of a heart attack.
Elf Sternberg
Never trust a hippy. (Score:1)
{
If I remember what I learned in Chemistry a few years ago, the critical mass of plutonium is about 2,000 pounds.. Meaning, in any warhead, there must be at least 2,000 pounds of high-grade plutonium to smash together in order for an explosion to occur.
2,000 pounds. Compared to 75.
Now, multiply that 2000 figure by the number of plutonium warheads that were tested out here in the desert, and out in the pacific for the past 40 years. Compare that figure against the 75 pound nuclear payload aboard the Cassini. The difference between the "threat" of Cassini and what _has already been released into the atmosphere_ is so laughably huge that it doesnt even warrant a concern on our part. You'de be more likely to have your life disrupted by tripping over a crease in the sidewalk than you would have it disrupted by Cassini coming back down to earth.
You need neither be a rocket scientist, nor a mathematician to figure out that all the whining over the Cassini probe is nothing more than radical hippy whiners who think we should make rockets out of hemp and fuel them with manure. The whinings occasionally get picked up by the media, which is why you're hearing about it here.
}
more_fun_flame_mode(off);
Bowie J. Poag
Re:plutonium IS that toxic (Score:1)
Re:But what's the benefit for science and humanity (Score:1)
BTW, from what I understand NASA rejected solar power because at the time it was not viable, and on a long journey you have a huge chance of those panels being destroyed by space debris. Don't you think NASA would rather use solar power? Which do you think is cheaper, 75 pounds of plutonium, or sun light?
Re:Now... (Score:1)
"In the seventh month of 1999
The Great King of horror comes from the sky,
To resuscitate the great king Angolmua
And before and after Mars will be to rule happily"
Nostradamus goofs again... NEXT!
Re:Agreed (Score:1)
Re:Conservation of energy (Score:1)
;P
Re:Agreed (Score:2)
Please stop spreading this myth.
Plutonium is a mildly radioactive metal that is also chemically toxic. A short article can be found here [umich.edu]. There are many chemicals that are far more toxic than plutonium.
Anti-nuclear activists would get more respect if they made scientifically sound arguments. Most of the anti-Cassini material appears to be written by people who flunked high school physics and chemistry.
plutonium isn't THAT toxic (Score:2)
Of course, No-one bothered with Galilleo (Score:3)
Nuclear Whining - The New Olympic Sport (Score:3)
{
Yeesh. All this whining makes me wonder why people aren't impressed with heavy-duty science anymore. Instead of the thrill of discovery, people would rather occupy their time panicking and whining about a 75 pound lump of "angry rock".
Reminds me of that episode in All In The Family where Gloria complains to Archie about how many people die every year by guns. Archie quips back, "Well little girl, would you be happier if they got pushed out of windows?"
Lets suppose for a moment that 75 pounds of plutonium *did* come hurtling through our atmosphere. First and foremost, it would probably be so badly degraded upon re-entry that it wouldnt matter *what* it was. You could send a damn dump truck full of boubonic plague through the Earth's atmosphere, it would probably disintegrate before ever reaching the ground. The earth is continually bombarbed by fairly large chucks of threatening debris 24 hours a day, 7 days a week, 365 days a year. Its been this way for millions, if not billions of years. There's a _reason_ why we arent living in a sea of craters, kids.
Besides.. Earth has already seen far worse man-made ecological disasters over the past 200 years than 75 pounds of plutonium could ever cause.
The Industrial Revolution, Hiroshima, Nagasaki, thousands of Cold War nuclear tests , Love Canal, Three Mile Island, Chernobyl, The Gulf War, just to name a few... I'd be willing to bet that if you took every single person who experienced irreversible physical illness as a result of these catastrophies, you could probably arrive at a figure of around 400,000 to 500,000 people grand total. And as tragic as those numbers are, they amount to less than one one-thousandth of a percent of Earth's human population. 75 pounds of plutonium, even *if* it came back to earth, would not reduce us to the level of a bunch of custard-eating Teletubbies living below ground for the next 10,000 years. Besides, i'd trust an engineer over a hippy, wouldnt you?
In other words, the 90's are over. We can all put down out guitars and quit whining now. Putting limits on what science can investigate is far more dangerous than sending a silly little spacecraft out for a spin.
}
wildly_inflammatory_editorial_mode(off);
Bowie J. Poag
Re:Of course, No-one bothered with Galilleo (Score:1)
Still, political sensitivities are high enough at this point that it's unlikely NASA will launch more high-profile missions using RTGs. That's a shame, but the bigger shame is that the NASA budget and in particular the planetary science budget may be savaged to the tune of $1 billion [nss.org] this year, killing most interesting new science missions. Dr. Evil is alive and well and living in the U.S. Congress, apparently.
Most sling shot maneuvers have a control burn (Score:1)
the craft falls with the fuel but does not carry that fuel back up .
Although
Squireson@bigfoot.com
I agree !! let us start a compaign (Score:1)
This would be high satire .
squireson@bigfoot.com
Re:We'll always have Titan (Score:2)
The airplane argument I mentioned earlier is this: I hate to fly. I'm absolutely terrified of flying. Really. So I don't fly unless I absolutely have to; it's a stressful experience that I would be all too happy to not have to deal with. However, given that I am strongly concerned about planes dropping out of the sky on a more or less random basis, why should I be put at risk of having planes that I'm not even in falling on _me_? There's no reason for pilots et al to risk my safety by flying planes at all, even if I'm on the ground.
The answer of course, is that if something is not immediately dangerous and extremely risky, it can be done without having to get approval from the people who may be effected. The Cassini probe was determined to not be likely to endanger people, and thus, it was approved. Had it not been considered to be sufficiently safe, it would never have gone ahead at all.
We'll always have Titan (Score:2)
The teacher in that class, who IMHO would ban himself if he realized that upon death he'll undergo radioactive decay, was always saying to his students 'Subvert the dominant paridigm.' And whenever he told his students to jump, every single one of the bozos asked how high.
I bashed through their anti-Cassini arguments like a knife through vaporized butter. My shining moment was when one of them complimented me for having subverted the dominant paridigm of the class. That was cool.
The moral is: stay far away from Gordy Fellman.
Re:We'll always have Titan (Score:2)
Most of my arguments for were rebuttals towards their arguments against.
People complained that NASA had no right to risk everyone. I replied that NASA does not really need to ask, that it is impractical at best to require everyone to ask for consent to risk (including the airplane thing, which I'll skip for brevity), and that the risk is quite low due to a number of factors. They include the precision of orbital mechanics, the success of previous RTG-equipped craft, the sturdiness of the RTG and the likely effects that the RTG could have in a worst case scenario.
Another person had asked why an alternative power source was not used (i.e. photovoltaic cells). I pointed out the low efficiency of said cells and that there is very little light from the Sun at the distance of Saturn's orbit and the dangers that the large number of objects in the Saturnian system pose to big ass solar panels.
Sadly, the class shifted to a mailing list, rather than continue to use the newsgroup (which was specific to that class!) for some reason after this whole thing wrapped up. Personally, I would have liked to rekindle it.