For spacecraft, you really can't beat the efficiency and simplicity of a nuclear power supply. From the Pioneer probes to the Mars rover Curiosity, a nuclear battery allows a slow drip of electricity where solar power would be impractical or impossible, and fuel cells or other batteries would drain. But radioisotope thermoelectric generators, as these are called, give a spacecraft about a household light bulb's worth of juice--and they need plutonium-238, an unstable and hard-to-obtain isotope.
The nuclear engineering wizards at Los Alamos National Laboratory have an alternative: Uranium-powered nuclear fission reactors that convert heat into electricity.
Scientists tested a new heat-pipe-based nuclear reactor in a test called DUFF, for Demonstration Using Flattop Fissions, in an experiment near Las Vegas recently. It's the first demonstration of a space nuclear reactor system to produce electricity in the U.S. since 1965, according to LANL.
It's a very simple design, using heat from a uranium fission reaction and transferring it to a pair of Stirling engines. A four-inch-diameter cylinder of enriched uranium makes up the core, and heat pipes cool it down, moving this energy into the engines. These free-piston engines produced 24 watts of electricity.
A real space-based engine would have to get a lot hotter, and would be able to produce about a kilowatt of electricity, but the experiment proved the concept can work.
More efficient nuclear power supplies would help spacecraft do their work and transmit their data more quickly, according to LANL. It would also allow NASA to use less plutonium, using materials that are a lot easier to obtain.
Eventually, the reactors could be scaled up into spacecraft propulsion systems, providing a reliable and safe fuel source for long-distance travel, LANL says.
Very nice work, more energy will allow missions we've only dreamed of until now. My concern with this is what's the fail safe mechanism? i can see where the imitator rod could possibly become stuck, due to expansion from heat, if the design tolerances are slightly off.
That's interesting, there is talk that Mars could be reached with a VASIMR ion thruster in 39 days.
Solid state is great, almost nothing can break with this one. But its basically a steam engine. huge waste of money, no wonder obama gutted nasa. All those scientists,all that time and money, and they build a glorified steam engine.
Even the giant nuclear power plants we use for power are basically "glorified steam engines." You great fool.
Good question (once again!). The rod (neutron absorber) is threaded into the core in a way where it cannot come out except with very fine controlled motions, and with the rod in place there are no conceivable accidents (e.g. launch explosions, high speed impacts, water immersion, etc.) that could cause the reactor to turn on. The rod will not be withdrawn to start the reactor until it has left the Earth (after which there are obviously no safety implications). Before the reactor starts the uranium is essentially non-radioactive, on the same order as the potassium-40 in our bones and bananas.
"That's interesting, there is talk that Mars could be reached with a VASIMR ion thruster in 39 days."
Something like VASIMR is indeed the end goal! The reactor to power VASIMR would need to use advanced technology (and would be extremely expensive to develop given our existing infrastructure). This concept can be considered the first, affordable step towards more advanced reactors to come.
VASIMR isn't going anywhere until they get a better power source. They need the nuclear power to supply the energy needed to heat the plasma. Yes nuclear power is a really glorified steam turbine. I thought most people knew that. Doesn't mean its simple and the process to create the fuel is what makes the process complex.
www.joesid.com - Where 3D meets Flash
almost every type of fuel burning power supplies are essentially glorified steam engines, this ranges from nuclear to coal to natural gas.
Steam works. Except when it explodes. Perhaps some way of harnessing the coldness of space to keep temperatures in check? I know space isn't that good for cooling since theres nothing for the heat to transfer into but I'm sure we could find a way to make it work.
1. Stirling engines are not glorified steam engines. They do not use steam, and are more efficient than steam engines.
2. This was built at Los Alamos National Laboratory, which is not operated by NASA.
This would make a great power source for an underground/underwater exploration vehicle on Mars or even Europa. The trick would be devising a way to convert the work of the Stirling Engines to propulsion for the submersible or rover to use.
Researchers and Scientists are just NOW designing and building this? I have no college education but I read a lot of science articles. I thought of this concept 20 years ago.
This was a joint LANL, NASA, NSTec effort. The Stirling engines were provided by the NASA Glenn Research Center, and were fabricated for GRC by Sunpower in Athens Ohio. Los Alamos developed the concept/experiment and executed the testing. NSTec provided the facility. Prior to the development of these new efficient, low mass, space qualified engines this concept would not be practical.
We just need to use thorium reactors makes more sense. And stirling engines are not steam engines gees. But look up Thorium 5 min on youtube it will blow your mind.
God bless the PopSci armchair scientist/engineers. Where would we be without your advanced knowledge and expertise. Surely these engineers and scientists that have more years of experience, and education than everyone on this comment section, could take a few notes!......end sarcasm
I am well aware that any nuclear power source is essentially a steam engine. I love stirling engines, i have seen the kits to build them, watched my father build them on several occasions. Stirlings work on heat differential. Even with thorium, this is a pitifully slow engine.
The risks of nuclear far outweigh the benefits. Its caveman technology.
VASIMIR is the future, brute force technology like combustion or steam engines are nearing the end of their usefullness. Magnetic technologies have far more promise then nearly obsolete ideas from the 1800's.
Deep space vehicles need technology that is rock-solid reliable with the lowest failure rates that can be engineered. The newest and most exotic technology is not necessarily the best for traveling far from Earth in a hostile environment.
Solid state is wonderful, but its too slow to be of any use. People will fly past voyager one day, at speeds that look impossible to us now. The money would be better spent refining "exotic" technologies so that they can be made more bulletproof. I should have clarified about the nuclear, in near earth orbit, or on earth, its a stupid technology. For long term thrust for an ion engine, it is a better power supply, although its likely that something better will come along in the next 15 years.
The reason that all most of space is remaining out of reach is because there is no focus, the chinese want to trumpet their supposed superiority, every one who can build a rocket and ship up a satellite does so, but there is no unified consensus on what to do. Even nasa, who used to lead the field continue to squander resources on projects that dont make any sense, economically or practically. What good is a solid state prototype that never makes it past the atmosphere? Even "armchair scientists" have sent rockets high enough to launch satellites.
In my opinion, focus on an engine that is fast enough to get people to mars and get it working. Once you have a fast engine, you can mine asteroids, (or whatever else) and take all the sting out of the budget cuts. Just because someone has a degree, it doesnt mean that they actually got good marks, or for that matter can even think , most "experts" are nothing more then parrots, reciting mindlessly by rote what they were taught by other parrots. Trolls tend to parrot the same "sarcasms" too. Post an original thought , something constructive or positive or troll someone else.
you obviously have no idea what a troll is by your failure to describe them and apply it to my comment, and my comment still stands. you are a armchair expert/scientist/engineer, as is par for these forums and it drives me nuts, you have no idea the constraints, reasons, issues, and eventual goal of this project yet you immediatly say its stupid, a waste of money, and these people working on the project have no idea what they are doing and that they have no imagination. Yeah sure a lot of novice scientist and engineers can launch rockets into low-low orbit. Does that mean they have the some knowldge let along understanding of the project to call it stupid and un imanginative? I think not. And your refusal to acknowledge Hillyrufuss's comment shows you know your beaten. Brand spanken new tech does not belong on operational missions. Sure test it, work all the issues out, i agree, but untill that exotic engine becomes a workable component to space travel, were going to need something else till then, like say this one.....
Space travel does not need to be fast, merely durable.
Our bodies are built to the limiting constrains of our biosphere, and so our presence in space is not about ships, but about habitats. We wouldn't think of putting cattle in space in a ship - we would think of putting them in designed space habitats. People are equally biological.
Thus, until we are building massive space habitats for us to colonize (which is the more efficient route than trying to create extra Earths on other planets), space is not about man, but about resources and robotics.
So, long term robotics working at great distances over time to build up resource pools from which resource growth can be exponentially developed IS the next step (unless a resource worth exploiting and returning here is found) - not shooting human bodies to far off rocks.
Too many science dreamers are drunk on Bradbury's Dandeleon Wine, and like the dandeleon are thinking that man will send his seed on the winds to far off distant lands, when man is much more like kudzu - growing over everything in every direction in a furious struggle for ever expanding resources (and choaking out everything else, often including parts of itself, in the process).
The problem with your comments are that you stubbornly stand by an archaic technology. Ignoring my initial comment about solid state being good, is far from ignoring hillrufuss comments, (he parroted) i had allready said solid state is fine in my first comment. Cant you read? Hopefully saying it twice in one sentence will help it sink in. Wasting money on a dead technology is like beating a dead horse to get it to walk faster. Move horse move! To mars in 3 years!
That aside, i have tremendous respect for the engineers, i hope that their gains can improve the size and weight of the reactors that archaic people still pin the hopes of space exploration on. Visionaries like Issac Isamov and Ray Bradbury are the reason these scientists have jobs, the public would have no intrest in space without the fictions that preceded the technology. The people i am insulting are the decision makers, the planners and the middlemen at NASA. You know, the people who arent even doing any real work.
There should be no new missions until there are technologies that can deliver what they promise. I will stand by my comments, NASA is a phenomenal waste of money, as is the rest of the american space industry. Archaic as the horse and cart, i know you want to defend your job ianredneck, but operational missions for PR reasons are another waste of time and money. You know as well as I do that the best stuff is purposely hidden for national security reasons. The old ways dont work anymore, retire and make way for the next generation of scientists. Mark my words the next big things will never come from NASA, unless they finally get permission to declassify.
While i agree with the durable oaksparr, all works of fiction merely reflect our own perceptual bias. What society agrees to becomes its reality. This quote sums it up best. (IMO)
A man staring at his equations
said that the universe had a beginning.
There had been an explosion he said.
A bang of bangs, and the universe was born.
And it is expanding, he said.
He had even calculated the length of its life:
Ten billion revolutions of the earth around the sun.
The entire globe cheered;
They found his calculations to be science.
None thought that by proposing that the universe began,
the man had merely mirrored the syntax of his mother tongue;
a syntax which demands beginnings, like birth,
and developments, like maturation,
and ends, like death, as statements of facts.
The universe began,
and it is getting old, the man assured us,
and it will die, like all things die,
like he himself died after confirming mathematically
the syntax of his mother tongue.
Like others, I'm sure, will suggest, dismissing a path of technology based simply on age or perceived obsolescence may keep scientific advancement more exciting and romanticized, but is more often than not impractical and expensive by any honest engineering standard. We don't abandon tried and proven technology for newer 'exotic' solutions to focus all our effort on those 'exotic' technologies; we pursue parallel development and switch only when the developing technology is mature enough to replace existing technology with minimal loss in reliability. Putting all efforts on hold until the next best technology is available would leave us sitting on our hands endlessly.
I'm curious, though, if you have a firm understanding of nuclear-based energy - enough so to wield the absolute certainty of such statements as you have made here.
Absolute and generalized statements such as "The risks of nuclear far outweigh the benefits" tend to throw up red flags. In what situations do the risks far out weigh the benefits?
It is reasonable to say that if, for instance, we are powering a small village of 100 people, then the risks do clearly outweigh the benefits (with currently available municipal plants). On the other hand, if we are talking about providing a high energy density power source to power a large population center with minimal fuel input and land requirements, the cost/benefit will likely lean towards nuclear. Generalizing the cost benefit to all situations is meaningless to any technical evaluation.
Further, simply stating a technology is archaic has some emotional impact for sure, but doesn't really further your point beyond that. Have you unilaterally decided nuclear-based energy is archaic? what has that opinion been based on (empirically)? perhaps you're basing it on the existing state of American nuclear power? Those plants are of course 30+ years old, granted, but hardly represent the current state of nuclear-based power (which generally is not permitted to be constructed for commercial/municipal use due to regulation).
"Solid state is wonderful, but its too slow to be of any use." is not a statement favoring "solid state" maybe you should read your own statements.
"There should be no new missions until there are technologies that can deliver what they promise" so for the next 20 years what are we supposed to do? And why do you assume i work with NASA....weird.....actaully sensing a great amount of paranoia from that post.
One word iambronco. Japan.
"sitting on your hands" is the best course of action because as far as i read, there is a tremendous fiscal cliff approaching for your country. (artificial as it may be) The most practical approach would be to seek ways to profit from space, and nuclear isnt fast enough. (unless you have invented brute force anti-gravity using nuclear power )
For example about the risks of nuclear, how is it practical to have to contain the spent fuel for at least 100,000 years? A 700g piece of radioactive material burnt up in the earths atmosphere and now everyone gets to breathe in a particle of it once in a while.
I despise romanticized technology, like nuclear. IF it works, it works. Hopefully VASIMIR works. If the time was spent on making it as solid state as possible, it would be more beneficial then trying to ressurect a dying type of energy conversion.
In addition, you are completely wrong about the larger facility being lower risk to population. The smaller facility is less cost effective but safer, because its easier to stop a smaller reaction then a larger one, in addition the larger facilities need larger and more elaborate failsafes. Hardly solid state and bulletproof. More like an accident waiting to happen.
Sure emotional statements make a stronger point , but the facts about nuclear power are very clear, to anyone who isn't directly benefiting from the industry. I have worked in yellowcake mines, talked to tons of engineers, declined tours of the mines which they say were safe, and decades later while they have died of cancer i am extremely healthy. Experience is far more valuable then something abstract, or learned from a book written by a teacher who spent their entire life in a lab.
IMO, nuclear energy is archaic because of its tremendously negative cost analysis. (long term storage of disposed fuel, environmental remediation / lawsuits to victims of meltdowns, near permanent pollution of arable land, maintenance, dead lakes due to frost heaved burms around containment ponds and more) Coal is cleaner when you factor in the long term. And coal is archaic as you can get.
Do you engineers ever factor in the human cost, as opposed to the financial cost?
While i dont agree with what you say, i am sure glad you are allowed to say it.
People hear or see the word nuclear power and they freak. Just a FYI. since the 1960's the U.S. has been building nuclear powered subs, aircraft carriers, and cruisers. The navy has 3 nuclear reactors in Idaho for training. To the best of my knowledge there has yet to be a meltdown, leak or explosion of any kind from these areas. So is there risk involved? yes, but should it dictate what we do? no. You risk dying in a car accident are you going to stop driving? can't take the bus same thing. Can't walk to work hit and run. Can't stay at home and work, your house might be struck by lighting and burn down. You could live in a bomb shelter, but what if an earthquake happens and it traps you? so that's out. With this fear; you and others have stopped someone from creating something new which just might benefit the human race. Think about that as we still stare up at the stars and wonder when will we go there?
So 3 mile island is a safe place to visit, or how about any of the test sites for nuclear weapons? great places for a family vacation?
theres the list of contaminated sites , some arent nuclear, and it doesnt include the classified ones. The human race isnt fit for the stars till they can take care of their own home. Its not about freaking out about nuclear power, its just that only uneducated people or improperly educated could possibly believe that its safe.
If you factor in the number of contaminated sites since the advent of nuclear technology, and calculate how long it takes to clean it up, and the cost, nuclear is far dirtier then coal. (and 40% of the worlds airborne mercury comes from chinese coal plants)
Heres a term ianredneck, pronoia. Nuclear is a fools dream.
heres a couple more supporting links for those who still think nuclear is a good idea.
although the upper link is left leaning, the lower link is a bit more scientific.
"So 3 mile island is a safe place to visit, or how about any of the test sites for nuclear weapons? great places for a family vacation?"
dkella, I was able to tolerate your tone for several messages, but I can't hold back anymore. TMI and test sites are perfectly safe - the dose outside the fence at TMI was no big deal the day of the accident, let alone decades later. Agreed that inhaling Radon day after day in unventilated yellowcake mines in the 40s and 50s was a bad thing (those guys were receiving huge concentrated doses to their lung tissue), but that doesn't compare in any way to your other examples. Our society has gotten to the point where a contaminated area is anything above background dose, while we have solid evidence the getting >10x background dose (radworkers, airline crews) poses no health/cancer risk, and good evidence that >100x background dose is not a risk (astronauts, unintentional high doses). I would love to force people to carry accurate radiation detectors with them in their daily lives; they would freak to know that over 10 million neutrons penetrate their body every day, how about 180 trillion neutrinos every second, etc. Oh no, my detector shows I'm getting hit by 25% more ionizing radiation when I go outside, I'd better hunker down inside. We need to put radiation back in context with all the other hazards out there - i.e. there's no metric that would show nuclear power killing more people than natural gas, even if that metric spans the 10,000 years that you're worried about.
Back to the subject, if we're going to expand into space we're going to have to shed our irrational fear of radiation - the doses out there in space are far higher than camping on ground zero at the Trinity Site.
I didn't read any of your comments... but my opinion on this article is they need to be investing more into what NASA is working on. Right now they are working on a real life warp drive. google it folks. its legit. I dont know why popsci hasn't done an interview with White, who's leading the project, or at least a decent article