Slashdot Mirror
Without Plutonium, Deep-Space Probe Missions May Sputter Out
cold fjord writes with this excerpt from Wired: "Most of what humanity knows about the outer planets came back to Earth on plutonium power. ... The characteristics of this metal's radioactive decay make it a super-fuel. ... there is no other viable option. Solar power is too weak, chemical batteries don't last, nuclear fission systems are too heavy. So, we depend on plutonium-238, a fuel largely acquired as by-product of making nuclear weapons. But there's a problem: We've almost run out. 'We've got enough to last to the end of this decade. That's it,' said Steve Johnson, a nuclear chemist at Idaho National Laboratory. And it's not just the U.S. reserves that are in jeopardy. The entire planet's stores are nearly depleted. ... what's left has already been spoken for and then some. ... Political ignorance and shortsighted squabbling, along with false promises from Russia, and penny-wise management of NASA's ever-thinning budget still stand in the way of a robust plutonium-238 production system." The plutonium shortage has been deepening for a long time, leading to some creative solutions. The Wired article alludes to the NASA project underway to create more, but leans toward gloom.
I'm sure that in 1985, plutonium is available in every corner drugstore, but in 2014, it's a little hard to come by.
Every normal man must be tempted, at times, to spit on his hands, hoist the black flag, and begin slitting throats. -HLM
We are no longer creating bombs for a nuclear apocalypse.
Mass doesn't disappear just because something is in outer space. That mass carries with it a certain amount of inertia, and the heavier something is on earth, the more energy will be required to manipulate it with any kind of acceleration, even in space.
File under 'M' for 'Manic ranting'
Launch price.
Shoving something out of ye olde gravity well is always expensive, if you go over the weight/size limit of one of the reasonably-commodified launch systems, things go from 'expensive' to 'heroically expensive'.
Depending on exactly what trajectory you have in mind, a more massive craft may also require more fuel/more powerful thrusters if you are making any course corrections along the way.
Yes, lifting facilities like Three Mile Island and Chernobyl off the ground takes a bit of effort
“He’s not deformed, he’s just drunk!”
Apparently Philo gives the secret of how to make plutonium from common household objects.
Likely because they need to be wrapped up in so much stuff so they're not killing everyone nearby.
And as far as I recall, you essentially need lead to block the radiation.
Lost at C:>. Found at C.
One of the helpful byproducts of a Liquid Floride Thorium Reactor (LFTR) is Pu-238
Source: http://flibe-energy.com/?page_id=64
Mass doesn't disappear just because something is in outer space. That mass carries with it a certain amount of inertia, and the heavier something is on earth, the more energy will be required to manipulate it with any kind of acceleration, even in space.
Avast, ye swab, once ye space corsair be a'sail in deep space, it be carried along on it's momentum as thar be little friction in a vacuum. Life support, unless ye enjoy sippin yer tea at 4 K, be yer greater concern. Also, ye be needin' a wee bit o' energy for changin the tack of yer corsair. Arr. ox)P-)
A feeling of having made the same mistake before: Deja Foobar
there are alternative isotopes, with much longer half lives even if battery weight is three or five times what a pu-238 one would be. not the heaviest thing in a spacecraft...anyway, the equipment to make the pu-238 exists, just a matter of getting serious about making the stuff
Fire up Rocky Flats and Hanford again to start building the next generation of nukes! That way we can get enough Pu-238 to power our deep space ambitions! I read on "The Onion" that the North Koreans are already building their deep space probe Kim Il Wang 1 which will reach out and spread communism to our neighboring galaxies! We can't afford to have a deep space probe power gap! We must contain the Red Menace!
Frankly with all the carcinogens in our air, amoebas in our water and a third of us with Toxoplasmosis, what's a little radiation folks?
Harrison's Postulate - "For every action there is an equal and opposite criticism"
By 2005, according a Department of Energy report (.pdf), the U.S. government owned 87 pounds, of which roughly two-thirds was designated for national security projects, likely to power deep-sea espionage hardware.
What on earth do they need deep sea espionage for? Are they trying to spy on Cthulhu or something?
Wrong Plutonium! We need US Plutonium which uses a different plug configuration and is only 120V, not that funny 204V stuff you use in the UK you insensitive clod! Shit, NASA would have to buy like one of those travel adapters or something to make UK plutonium work in NASA probes and that would probably like throw off the gyroscopes or something.
Harrison's Postulate - "For every action there is an equal and opposite criticism"
That's the wrong kind of Plutonium. RTGs need Plutonium-238. That stockpile is Plutonium-239, 240, 241, and a bit of 242.
upon the advice of my lawyer, i have no sig at this time
>it's
Land-lubber.
Twasn't an apostrophe, ye dog. It be the stray mark of a sharp cutlass.
What part of `yes no` don't you understand?
A very long time ago I was in the Navy, sailing about in a nuclear submarine.
The power plant of that submarine outmassed the ISS.
"I do not agree with what you say, but I will defend to the death your right to say it"
* Build a moon base
* Setup solarpanels for lots of power generation
* Build infrastructure
* Extract lots of Helium 3
* Build a monorail assisted launch system
* Build space ship parts
* Build a Tokamak in parts, small enough to assemble in space
* Launch all the s#!+ into space and assemble all the parts
* Remember to launch a couple of tons of H3 too
* Go!
The problem is that the Dept. of Energy, although hugely wasteful, cannot "afford" to make plutonium for NASA/JPL. Yet another way this and previous admin is trying to gut planetary science: http://www.planetary.org/blogs/casey-dreier/2013/20130913-the-doe-is-full-of-wasteful-spending-but-forbidden-to-help-nasa-make-plutonium-for-space-missions.html
If we start filtering that water over by their nukes, we can create a number of batteries that can provide power for mars and the moon.
Except we don't want our first probe to make contact with an alien civilization to be powered by radioactive sea bass. There's just no good explanation for that.
But I should think the minimum safe distance from an unshielded reactor would preclude anybody actually getting near enough the spacecraft to prep it for launch.
A fission reactor that has been assembled, but never operated, does not produce much radiation. Enriched uranium and/or pure plutonium are not particularly dangerous (unless inhaled or ingested). It is the fission byproducts from actually operating the reactor that are dangerous. Even this minimal radiation could be avoided by using temporary shielding that is removed (possibly by a robot) immediately before the launch.
I thought NASA struck a deal with DOE back in March to do 2 kilos per year of Pu-238 back in March. Did it get de-funded or something? http://www.universetoday.com/100875/u-s-to-restart-plutonium-production-for-deep-space-exploration/
[RIAA] says its concern is artists. That's true, in just the sense that a cattle rancher is concerned about its cattle.
Pu-238 is NOT "weapons-grade", and Pu-239 (which is) is NOT a useful substitute for Pu-238.
"I do not agree with what you say, but I will defend to the death your right to say it"
WHAT WOULD HAPPEN?
The reactor would mostly likely fall into the ocean, where it would be retrieved intact. RTGs are designed to survive a launch failure, and several accidents have
already happened, without any significant release of radiation.
Probably not; a sub's reactor would likely depend on the presence of the ocean for part of its cooling system (cooling is always a big problem in space -- basically it can only be done with radiators, which isn't very efficient), and is surely way overpowered for most missions.
The US and Russia have sent up actual reactors before. The US had SNAP and the USSR had BES.
But you really don't need nuclear power sources at all unless you're either far from the sun (beyond the orbit of Mars, usually), have serious power needs that modern solar power isn't sufficient for (the recently landed Curiosity rover on Mars uses an RTG for main power), or need heat to keep systems from getting too cold (the solar powered Mars rovers had small RTGs in them for heating purposes, IIRC).
-- This and all my posts are in the public domain. I am a lawyer. I am not your lawyer, and this is not legal advice.
Consider it costs from $2000 (Falcon 9) to $30,000 (Pegasus) per lb. to launch a payload from Earth. And the present maximum launch capability is, IIRC, about 150 tons. Anything bigger has to be launched in pieces. For probes going anywhere besides Earth orbit, that 150 tons has to include the additional rocket stage to push the probe out of the Earth's gravitational influence. So the probe itself is likely to be under 1/2 ton. Now, make a reactor that fits.
Having said that, I've been casually wondering if a small MSR (Thorium) reactor could be used. It provides both heat and power, and its characteristics make it plausible that an under-10-ton reactor could be made. Such a reactor could provide the heat for propulsion of the probe, plus lots of electricity, and it can be turned on and off at will, or throttled. So this might work in a large vehicle. Of course nobody has even started on the engineering required to make a liquid reactor work in microgravity (no convection, no heat conduction to dump waste heat).
It's easier to be a result of the past, but more fun to be a cause of the future! http://www.spacefinancegroup.com/
Many other isotypes and generator types.
Strontium-90 is a good substitute for shorter trips. Americium-241 is very close to being a reality for longer trips. There is also the Safe Affordable Fission Engine project https://en.wikipedia.org/wiki/Safe_Affordable_Fission_Engine
But there is another type of electro-mechanical rotating generator designed for Russian craft, TOPAZ-II, but, unfortunately, it's far too heavy.
Kriston
That big yellow ball in the sky is emitting more radiation than that little chunk of P238. You might not be aware of this but without the earths magnetic field and atmosphere in the way that little ball of light would kill you very very quickly.
As others have already noted that P238 isn't really dangerous unless you are going to eat it. Though plutonium is believed to be an entirely a man-made material uranium and all the other naturally occurring radioactive elements exist outside the earth as well as on it. The several ounces on a space probe used as a thermolytic generator is insignificant entirely.
Exactly!
Don't Pollute Space With Radiation!
I drank what? -- Socrates
Neither of those substances are overly dangerous or radioactive. It's the stuff with shorter half lives that you have to worry about. It decays faster, and pound-for-pound will release a greater amount of radioactivity in a shorter time scale.
PU-238 has a half life of 87.7 years. It will be cold and inert thousands of years before entering another star system.
I want peace on earth and goodwill toward man.
We are the United States Government! We don't do that sort of thing.
Most probes use a boom rather than a tether. Look at pictures of pretty much any probe, like Voyager, Galileo, Pioneer and you'll see RTGs mounted out on booms away from the main body of the probe.
When our name is on the back of your car, we're behind you all the way!
See, this is why people who don't understand radiation shouldn't talk about it.
4.5 billion years of half-life means that the decay rate - the actual process that emits radiation - is so absurdly slow that the material itself is just not dangerous. The dangerous stuff is, almost by definition, the stuff with *short* half-lives. A gram of material with a millisecond half-life will release more radiation in one second than a kilo of U-238 will in a century, assuming they undergo the same types of decay. Secondary decay of the uranium will be a bigger problem, and still not much of one.
In fact, people have incorporated U-238 into everything from building bricks for houses to the glaze on pottery. Let me make that clear for you again: people have built houses out of material containing uranium ore. They have then lived out their natural lives - and sometimes the lives of several generations of a family - in those houses.
Calling it "spewing poison" is bullshit of the first degree. It's probably more dangerous to eat bananas (which contain radioactive potassium isotopes, in tiny amounts, but with much shorter half-lives) than it is to have U-238 all around you. Even pure, enriched U-235, while not something you'd want to hold in your hand, is not particularly dangerous to handle so long as you keep it away from neutron guns or reflectors, and below critical mass.
There's no place I could be, since I've found Serenity...