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The concern was that performing a slingshot around Earth with a RTG-equiped probe has risks. If early in the mission the probe loses the ability to guide itself

by cjensen 11y ago

The concern was that performing a slingshot around Earth with a RTG-equiped probe has risks. If early in the mission the probe loses the ability to guide itself, then the probe may be off course enough to hit Earth. The Cassini mission to Saturn did this with an RTG, and there was a significant outcry about the plan.[1] [1] https://en.wikipedia.org/wiki/Cassini–Huygens#Plutonium_power_source https://en.wikipedia.org/wiki/Cassini–Huygens#Plutonium_powe...

sillysaurus3 11y ago
"Had there been any malfunction causing the Cassini space probe to collide with the Earth, NASA's complete environmental impact study estimated that, in the worst case (with an acute angle of entry in which Cassini would gradually burn up), a significant fraction of the 33 kg of plutonium-238 inside the RTGs would have been dispersed into the Earth's atmosphere so that up to five billion people (i.e. almost the entire terrestrial population) could have been exposed, causing up to an estimated 5,000 additional cancer deaths (0.0005 per cent, i.e. a fraction 0.000005, of 1 billion cancer deaths expected anyway from other causes), but the chance of that happening were less than one in one million." Would it be true to say that your loved ones are thousands of times more likely to die in a car crash than in the worst-case scenario of this project? This is a stupid reason for having an outcry.
- DanBC 11y ago
  but we know from all those "the pig that wants to be eaten" philosophy questions that this stupid outcry is normal and predictable. More interesting would be how to present information to reduce the outcry.
- cjensen 11y ago
  To be clear: I'm describing the outcry, not expressing an opinion on it.
- GFK_of_xmaspast 11y ago
  If I read that correctly that there's a one-in-a-million chance of killing 5k people, the expected number of deaths over all alternative universes is 1/200. Additionally, one has to consider the non-plutonic fallout and its consequences of NASA as an agency and space exploration in general.
- elorant 11y ago
  There’s a huge antiscience group of people out there. Let’s just not give them yet another excuse to attack science. They could inflate numbers and make it sound like NASA is endangering the health of millions of people for generations to come. We’ve heard crap like that before.
  - CamperBob2 11y ago
    Sadly, the particular antiscience group that tried to stop the Cassini launch was more or less led by a popular, (then) well-respected physicist, Michio Kaku. [1] For that reason, his name should not be forgotten by posterity, the way it was almost forgotten by me until this thread popped up. [1] http://prop1.org/2000/cassini/9707kaku.htm http://prop1.org/2000/cassini/9707kaku.htm
- vacri 11y ago
  > This is a stupid reason for having an outcry. What about "Let's add risk to strangers' lives so we can look at a comet slightly longer"?. Throw in that 'one in one million' is a number pulled from the air to represent an opinion, not calculated mathematically, and that launching probes happens multiple times, not as a once-off event. Let's keep things in perspective here. What happens if that burnup happens over a country like Russia or China? And if you're going to make the "well, only 5000 people would die" argument, then you've lost already. Out of the global population that live and work in buildings, the World Trade Center attacks killed fewer than 5000 people. Overzealous police shooting people in the streets? Bah, it's hardly anyone, by the numbers. Wildfire sweeps through the state, killing 50 people? Drop in the ocean compared to car deaths, why is anyone concerned? "They were going to die anyway" is a pretty callous argument that can be used against anything. I mean, if we're arguing for science here, then we should also be pointing out the flaws in the quoted paragraph - it doesn't matter how many other deaths are attributable to cancer (and doubly so because cancer isn't a single thing anyway). Mentioning that statistic in this context is purely political and poor science. I say all this because the process of cutting edge science is necessarily political. You see it in academia, you see it in industry, and you see it in government funding.
  - 7952 11y ago
    Yes I agree. Science has no opinion whatsoever about the ethics of this, it can merely predict possible outcomes. The actual decision has to be about more than the statistics and include other factors. It may be worth the risk sometimes and not others. But public deaths is categorically unacceptable however you make the decision.

by cjensen 11y ago

sillysaurus3 11y ago

"Had there been any malfunction causing the Cassini space probe to collide with the Earth, NASA's complete environmental impact study estimated that, in the worst case (with an acute angle of entry in which Cassini would gradually burn up), a significant fraction of the 33 kg of plutonium-238 inside the RTGs would have been dispersed into the Earth's atmosphere so that up to five billion people (i.e. almost the entire terrestrial population) could have been exposed, causing up to an estimated 5,000 additional cancer deaths (0.0005 per cent, i.e. a fraction 0.000005, of 1 billion cancer deaths expected anyway from other causes), but the chance of that happening were less than one in one million." Would it be true to say that your loved ones are thousands of times more likely to die in a car crash than in the worst-case scenario of this project? This is a stupid reason for having an outcry.

DanBC 11y ago
but we know from all those "the pig that wants to be eaten" philosophy questions that this stupid outcry is normal and predictable. More interesting would be how to present information to reduce the outcry.
cjensen 11y ago
To be clear: I'm describing the outcry, not expressing an opinion on it.
GFK_of_xmaspast 11y ago
If I read that correctly that there's a one-in-a-million chance of killing 5k people, the expected number of deaths over all alternative universes is 1/200. Additionally, one has to consider the non-plutonic fallout and its consequences of NASA as an agency and space exploration in general.
elorant 11y ago
There’s a huge antiscience group of people out there. Let’s just not give them yet another excuse to attack science. They could inflate numbers and make it sound like NASA is endangering the health of millions of people for generations to come. We’ve heard crap like that before.
- CamperBob2 11y ago
  Sadly, the particular antiscience group that tried to stop the Cassini launch was more or less led by a popular, (then) well-respected physicist, Michio Kaku. [1] For that reason, his name should not be forgotten by posterity, the way it was almost forgotten by me until this thread popped up. [1] http://prop1.org/2000/cassini/9707kaku.htm http://prop1.org/2000/cassini/9707kaku.htm
vacri 11y ago
> This is a stupid reason for having an outcry. What about "Let's add risk to strangers' lives so we can look at a comet slightly longer"?. Throw in that 'one in one million' is a number pulled from the air to represent an opinion, not calculated mathematically, and that launching probes happens multiple times, not as a once-off event. Let's keep things in perspective here. What happens if that burnup happens over a country like Russia or China? And if you're going to make the "well, only 5000 people would die" argument, then you've lost already. Out of the global population that live and work in buildings, the World Trade Center attacks killed fewer than 5000 people. Overzealous police shooting people in the streets? Bah, it's hardly anyone, by the numbers. Wildfire sweeps through the state, killing 50 people? Drop in the ocean compared to car deaths, why is anyone concerned? "They were going to die anyway" is a pretty callous argument that can be used against anything. I mean, if we're arguing for science here, then we should also be pointing out the flaws in the quoted paragraph - it doesn't matter how many other deaths are attributable to cancer (and doubly so because cancer isn't a single thing anyway). Mentioning that statistic in this context is purely political and poor science. I say all this because the process of cutting edge science is necessarily political. You see it in academia, you see it in industry, and you see it in government funding.
- 7952 11y ago
  Yes I agree. Science has no opinion whatsoever about the ethics of this, it can merely predict possible outcomes. The actual decision has to be about more than the statistics and include other factors. It may be worth the risk sometimes and not others. But public deaths is categorically unacceptable however you make the decision.