It begs the question of just how much money and resources have been spent on the endeavor of killing and how much further we would be as a race if it wasn't so out of control. Last time I looked the US spent about half its budget on the military to protect 'our way of life' meanwhile the everyday citizen is subject to their rights being trampled, limited prospects for employment and anyone who speaks up for themselves is labeled a tewworwist. Meanwhile war, now, is the ultimate reality TV show where the minds of millions are manipulated by the mass media.

But tomorrow will be a better day and the new military robots will protect us all from subjugation, so happy days!!

A Developer, Developer?

Well mass was the main point I was making, not just because of the weight of an RTG but because of the associated control systems, stronger landing gear and so on. However another poster pointed out the mass is similar to the solar panels for the required RTG so perhaps my point is moot.

Either way, I think that the conversation is somehow painting the mission as a failure, when I think it was actually a success. The first landing on an asteroid didn't go as it was intended and I think something similar happened for Apollo - except that people were there to handle it. Maybe it will collect enough power to start up again, I hope so.

Thanks, I know what an RTG is, however i didn't know that was it's mass.

We can only hope...

I'm not certain how you would power a lander with solar wind however even with a slow velocity of 400Kms a second, I think it's safe to say solar winds would kill birds.

Whilst it is an appropriate use of a nuclear power plant, I'm sure the mass of a nuclear powered probe would have increased the costs and complexity of the launch and landing whilst decreasing the science payload.

I think it would have been far easier just to make sure the harpoons *actually* fired. If it was nuclear powered the probe may have just smashed, instead of bounced, the additional mass. The problem wasn't the power source, it was the landing harpoon. We have never landed on an asteroid before and these are, inevitably, the lessons that have to be learned.

The sun is a perfectly functional fusion reactor, so why wouldn't you use it for power? Had a nuclear plant been installed the probe would have had a guaranteed end of life, where as the panels afford the craft the possibility of functioning indefinitely. Had you been talking about a probe set to go well away from the sun then absolutely and pu-238 power plant would be a great idea.

I'm surprised it is not posted here many many times as, for once, it may be on topic.

It would seem that even the possibility of bipartisanship is completely dead in America and that the possibility of actually resolving and solving the structural issues is lost in a ratcheting of political "solutions" designed to conceal their real intentions.

It's such a disappointing thing for such a great country when the political parties responsible for the stewardship of the nation can only look after their interests at the expense of everything else.

A scientific calculator!

Radiation vs Radionuclide.

Yep, you're right, thanks for pointing that out about the destination of the micro nutrient.

The issue is the radio-isotope's journey through a body if it is a analogue of a micronutrient that body uses. Tritium it is mutagenic to DNA at 0.018590 MeV for beta emissions and Caesium-137 is a beta and gamma emitter at 1.176 MeV so it is much more energetic. C137 gets organically bound and that increases the decay rate into the tissue, it doesn't seem to be used in medicine so I would prefer not to have a gamma emitter floating around inside me as it decays, whatever it gets attached to for 30 odd years.

However, whilst I think the risk of direct exposure to C137 is low, it is in the food chain and it has its own way that it bio-accumulates for 30yrs*20 decay cycles, around 1400 years, not as much as some other radioisotopes but longer than anyone living today.

Many of these products decay in geological timeframes so the amount of time they are toxic in the foodchain is a serious concern. US coast is protected by those deep currents washing the cold deep water. To test for and to identify other radio-isotopes you would need a proper government effort, perhaps international effort to determine exactly which radioactive products of Fukushima have contaminated the Pacific Ocean and the quantities it will continue to pour into the pacific ocean.

All we know right now is, they weren't there before, they are now and that it only took a couple of years to get across the Pacific. This will continue to unfold for many many years.

There is no safe level of ignorance either.

You are incorrect. Small doses are highly toxic because the meabolism transports them to sites around the body where they continue to emit radiation and gestate cancer. Oppenheimer's own research found pu-239 to be fatal at 1-10 micrograms, toxic as an inhalant or when ingested. So your statement contradicts even the 50 year old science.

As for energetic levels, and depending on the radio-isotope analogue, if they are beyond a certain level they are cancerous, if they are below a certain level they are mutagenic to the DNA and cause transgenic disease. So, no, there is NO safe level of exposure just whether you or your progeny experiences the consequences.

As for your "comparison to many things that we do in everyday life that we consider safe", any risk of exposure is measured against the severity of consequences. An argument like that presupposes that you have control over your exposure to the risk, which you don't have with radio-isotope exposure in the foodchain. The difference with Fukushima is that the risk is being increased e.v.e.r.y.d.a.y and no-one has any control over that exposure anymore.

This leads to the fundamental point missed in this argument. WHOI, with a small budget detected C137 of the coast of the US with just 50 samples from the pacific ocean. No government funding, one boat and a small group of dedicated scientists. Should we just assume that the rest of the ocean is hunky dory and "just the bits they were checking" happened to have radioceasium in it?

That is why there is no safe level of ignorance.

For example pu-239 whose halflife is 25,000 years and is fatal to humans in the 1-10 microgram range.