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Philae's Lost Seven Months Were Completely Unnecessary
StartsWithABang writes: This past weekend, the Philae lander reawakened after seven dormant months, the best outcome that mission scientists could've hoped for with the way the mission unfolded. But the first probe to softly land on a comet ever would never have needed to hibernate at all if we had simply built it with the nuclear power capabilities it should've had. The seven months of lost data were completely unnecessary, and resulted solely from the world's nuclear fears.
Firstly, what caused the problem was not "Nuclear fear", but failure of the harpoon to hold Philea down. The solar panels would have worked fine otherwise.
Secoundly, Plutonium-238 is simply no longer available - nobody makes it anymore. The reason why is because it is created using a dangerous and expensive process by irradiation of neptunium-237.
Yes it will, you just have to manually click the "Continue to site" link in the top right corner.
What bollocks is that? What has an RTG in space to do with a nuclear (fission) reactor on earth?
Nevertheless, a bunch of fearful and uninformed people vigorously protested Cassini and it's RTG. Sky is falling, something something we're all going to die!
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Space probes do get started on earth, and have to go through a somewhat unreliable launch process to get to space. There is a fear that if the rocket were to blow up, radioactive material released into the atmosphere would be dangerous.
It almost certainly wouldn't be. Even in the worst-case scenario, that the RTG vaporized on reentry, it would be heavily dispersed. Still, NASA calculated for a similar case, there could be several thousand deaths (page 66). (Not that you could peg any one death to it, but rather thousands of additional cancers compared to not having an accident with an RTG launch failure.) Plus some land contamination with radioactive dust.
So it's not completely insane to be concerned. They figure your personal odds of dying because of it to be one in a trillion, which most of us would say is too low to think about. But I can understand why a few people might say that even one-in-a-trillion (especially since it's repeated for everybody on the planet) is worth considering. It's not as simple as having it millions of miles away in space.
Has all to do. Fear of RTGs caused a lot of noise surrounding Cassini, which went on and echoed. By the time Rosetta/Philae were designed, as stated in TFA:
All previous deep space probes have used RTGs [Radio-isotope Thermoelectric Generator], but the ESA has not developed RTG technology. They couldn’t get it from NASA (who wouldn’t provide it) or Roscosmos (which would violate the ITAR treaty).
And people go "oh no they can detect the radiation IN CALIFORNIA ITS LIKE THE TITANIC BUT WITH BEARS EVERYBODY PANIC!!11111ONE!11ONEoneleven1!11"
Which is actually a testament to the astonishing sensitivity of modern equipment. The level of radation in california is 8 disintegrations per cubic meter per second. That's 8 whole atoms per second in a tonne of water. That's 8 out of 100000000000000000000000000 atoms (that's actually the right number of zeros give or take).
It's also about an order of magnitude below the background radiation from naturally occuring stuff in the water, never mind the incoming cosmic rays and stuff from the ground and food.
Another fun fact: the Super-K detector can pick up the signature from relatively nearby nuclear submarines that aren't leaking any ionising radiation at all.
Instruments are sensitive.
SJW n. One who posts facts.
Yeah, that table is based on LNT, a "theory" with less supporting evidence than Santa Claus. Actually, that's not fair to Santa, since the evidence directly contradicts LNT. But LNT is mandated by law in many cases, which you should keep in mind the next time someone tells you that the left is pro-science.
LNT is "Linear, no threshold". According to that nonsense, a radiation dose expected to cause cancer in a person, but distributed over 7 billion people still causes 1 "extra" cancer in the world. This dose may not even be detectable, by the way, and would be far smaller than the ordinary background radiation levels.
In reality, people with occupational radiation doses have lower cancer rates than the general population.
See that "Preview" button?
While it is true that people are not dropping dead in the thousands due to Fukushima, I'll leave this to consider:
Whether the estimate is correct or not, it will take decades before it's safe to say "a nuclear reactor that didn't kill anyone". The actual outcome will also largely depend on how well the Japanese authorities will handle the cleanup. Judge for yourself whether they've done a good job so far.
I hope I didn't brain my damage.
Radioisotopes that last "longer than humankind has been in existence" are so weakly radioactive, and so small a part of a nuclear event, that we can ignore them. The most dangerous isotope in an accident is I-131, which has a half-life of eight days. That's a lot of energy it has to release in a short time.
I think you are nitpicking the definition of "available". Yes, the fuel existed at the time, that doesn't mean the fuel was available for this mission. A high risk, relatively low reward, limited life lander almost certainly doesn't merit using 1/10th of the available reserves.
Don't think it was high risk? The lander failed in multiple different ways on deployment and was able to do science by little more than dumb luck (not discounting their success, dumb luck plays in important part in everything and it was their engineering and planning that allowed the landing to succeed despite those issues). Don't think it was low reward? Most of the science the lander was designed for was completed on batteries during the 60 hour window after landing. Don't think it's limited life? In a few months, the comet is going to start out gassing and the lander will almost certainly be disabled.
If Pu-238 were still in production the math works out differently. If the lander had been a more central part of the mission it might be different. If the comet were on it's way out of the system instead of in that could change things too (though then Rosetta would also need an RTG). The point is: it's not binary. It's not "the fuel is right there lets use it". There's a cost, and a benefit to using it in this probe rather than the next one.
In fact, there is NO valid example of a LNT toxin in nature. If you reduce the concentration of any toxin in, say, water, there is always a point at which its medical impact drops to zero while there is still some toxin present. This is because natural selection ensures that we can survive the amount of that toxin that we normally find in the environment. This includes the constant drizzle of background radiation that we live in.
In fact, the scientific term for belief in LNT in chemistry is "homeopathy."
The claim of the political reason is without reference. However, the article correctly states that ESA does not have RTG technology and no one was selling RTGs at that time.
the 24,000 [year] half life
TFA refers to Pu238, which is quite active. It has a half life of about 88 years. It is an energetic alpha emitter, which is not dangerous outside the body because the skin absorbs the emission and you can wash Pu238 off pretty easily. However, once it's inside you, virtually all of the alpha emissions will be absorbed by your body unless/until you can excrete it. A good fraction of any amount ingested will eventually emit energetic radiation that you will absorb. A disaster could be bad.
Having said all that, including Pu238 in a spacecraft is a problem we have solved before, so it's not all that crazy.
RTG's ARE containers designed to survive catastrophic launch failures. We're not talking about nuclear reactors here
A Thorium molten salt reactor would be able to produce Pu-238 without any considerable proliferation risk.