The US Government is Taking a Serious Step Toward Space-Based Nuclear Propulsion (arstechnica.com) 80
Four years from now, if all goes well, a nuclear-powered rocket engine will launch into space for the first time. The rocket itself will be conventional, but the payload boosted into orbit will be a different matter. From a report: NASA announced Wednesday that it is partnering with the US Department of Defense to launch a nuclear-powered rocket engine into space as early as 2027. The US space agency will invest about $300 million in the project to develop a next-generation propulsion system for in-space transportation. "NASA is looking to go to Mars with this system," said Anthony Calomino, an engineer at NASA who is leading the agency's space nuclear propulsion technology program. "And this test is really going to give us that foundation."
NASA should consult with the military (Score:2, Funny)
Did they give up on reverse engineering the UFOs they recovered that bend space-time as a propulsion method?
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Who is the real owner of the White House crack bag?
Re:Nuclear Propulsion = Radiation Death Chamber (Score:5, Insightful)
Go tell the navy to stop making nuclear subs then. Also, you might want to educate yourself.
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...that man is a doctor so he knows what he is talking about. Are you a doctor?
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Keep up to date with your COVID booster every 6-9 months.
"Doctor" is not a synonym for "physician". (Score:5, Insightful)
...that man is a doctor so he knows what he is talking about.
Well, a chiropractor, anyway.
Re:"Doctor" is not a synonym for "physician". (Score:4, Insightful)
chiropractor = quack
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Total quake?
He said subluxation not subduction!
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By the mention of "vertebral subluxation" I'm going to guess chiropractor. So the kind of doctor the fake ones call a fake one.
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Re:Nuclear Propulsion = Radiation Death Chamber (Score:5, Informative)
It's actually not much of a different process. Nuclear reactors use their heat to turn water from liquid to gas and use the force produced by the increased pressure to spin turbines. Nuclear rockets use their heat to turn hydrogen from liquid to gas and use the force produced by the increased pressure to provide direct reactive force. Either way you use heat to turn liquid to gas to push something.
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It's also not the propulsion the original respondent was talking about. He's assumed NASA is testing the more powerful H-bomb method instead of some placid heating of hydrogen that's only a step up from an ion drive.
"vertebral subluxations" (Score:5, Insightful)
Any astronaut going into space is exposed to high levels of radiation, that much is well known. Nuclear propulsion will expose them to hundreds of times the levels of radiation they will be exposed to already, this is insane.
Turns out-- you will find this hard to believe-- astronautical engineers actually do know about radiation, and designs for human-carrying nuclear vehicles incorporate shielding.
What's even worse is that NASA does not have any proper post-flight chiropractic care for its returning astronauts.
They use physicians. In fact, something like a quarter of the astronaut corps are MDs. [wikipedia.org]
They come back to earth, riddled with radiation-fuelled vertebral subluxations, and are not treated for them. Over time these life-stealing subluxations will manifest themselves into heart dis-ease, cancer, diabetes, and countless other life threatening maladies.
So far that has not manifested.
Radiation effects on humans are moderately well studied [cdc.gov], and I suggest you learn something about them before you comment by randomly throwing around jargon. The main effect of radiation to worry about is cancer, which turns out to be due to actual DNA damage, not to "vertebral subluxations".
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'Dr' bob is just a quake.
Shielding [Re:"vertebral subluxations"] (Score:3)
Actually, the amount of radiation from the nuclear reactor is far far less than what they get from being in space.
Depends on shielding and how far you are from the reactor.
Fission reactors are necessarily sources of copious amounts of neutrons, which are hard to block. No problem on Earth (concrete is cheap, you can use lots of it), but there's a good reason that most nuclear rocket designs are long and skinny [cloudfront.net], with the reactor at one end and with humans and electronics on the other. Getting far away helps, and also means you only have to shield the direction toward the crew and cargo section.
But, yes, with a well-engi
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The original poster's comments are bizarre. Thank you for a simple, insightful, educated response. I suspect that most Slashdot reader's already know this, and the one person intended to be enlightened by your comments will likely not "get it".
One point of further clarification, radiation damages DNA, but consequences are "dose" dependent. At sufficient exposures, cell DNA is damaged enough that cells cannot divide at all and they "disappear". Epithelia (the "lining" tissues of the body) and bone marrow
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Thanks for the clarification.
Yes, I was implicitly talking about long-term exposure, not acute radiation exposure.
Re:Nuclear Propulsion = Radiation Death Chamber (Score:5, Interesting)
The fictional ship Discovery One from 2001 A Space Odyssey was designed by Arthur C. Clarke specifically to deal with this problem. The crew quarters where in a sphere at the head of the ship containing a centrifuge section to provide artificial gravity. The nuclear propulsion unit was at the rear of the ship, separated from the crew section by a 200m long boom which carried supplies, fuel and equipoment that wouldn't be affected by radiation. Clarke also provided the nuclear section with vast, sail-like cooling surfaces to deal with the excess heat, but Kubrick deleted them because it would confuse the audience.
To this day, over a half century after the movie came out, it's hard to imagine a more plausible manned space ship for visiting Jupiter -- the original target of the Discovery One mission -- in a reasonable amount of time. While you can reach Jupiter in a little under two years, if you want to reach Jupiter orbit it would take over five years using conventional engines and gravity assist. Saturn is much farther. It takes 3-4 years just to do a fly-by. It took Cassini seven years to insert into an orbit of Saturn.
The planned orbital insertion into Jupiter in just two years would almost certainly be impractical with the specific impulses attainable with conventional chemical propulsion. To raise your specific impulse, you need to part a lot of kinetic energy to your reaction mass, which in turn means you need to achieve very high levels of volumetric and mass energy density in your fuel. That's where E=mc^2 is your friend.
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The fictional ship Discovery One from 2001 A Space Odyssey was designed by Arthur C. Clarke specifically to deal with this problem.
As was the Antares [imgur.com] on the 2009 TV show Defying Gravity [wikipedia.org], which was purportedly 1/2 mile long, though originally conceived to be longer. From ship/show set design article: Defying Gravity’s Stephen Geaghan – Future By Design [wordpress.com]:
The Antares started off as a mile in length, but when I began doing my calculations it was, on a human scale as well as TV scale, too big of an environment to comprehend.
“So we cut it back to half-a-mile, and still, a human being on the surface looks like an ant compared to the size of the ship. It’s a gigantic ship with a sun shield on the front that measures 600 meters. Each compartment is a cylinder that is 28 feet wide and 50 feet long.
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He's a troll pretending to be a chiropractor. And their hypothesis is that essentially ALL illness in the body comes down to spinal health with other body systems being stimulated [or not] by improper signals caused by those spinal health issues.
Re: Nuclear Propulsion = Radiation Death Chamber (Score:1)
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That's not fair. Some chiropractors are physiotherapists who couldn't get into a physio program. Or massage therapists who wanted to tell their parents they were a "doctor."
There are lots of reasons to go to quack school.
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Most massage therapists are quacks too. We actually go to a school for massages on the cheap and that place is littered with crystals, herbal remedies, and various fake remedies for recovery after pregnancy. Of course, they do have a chiropractor on staff. In fairness though, our actual doctor's office isn't looking much different these days. They might not have the crystals but they are definitely pushing overpriced herbal supplements and have an adjoining "medical spa" and pain management center.
A chiropr
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That stuff works. It's called the placebo effect, and it was probably the most effective medicine available up until sometime in the 20th century.
Chiropractic, on the other hand, espouses all sorts of bullshit that is actually physically harmful. Many chiropractors today ignore the dangerous nonsense and only do the possibly beneficial (evidence is scant) things, but the field itself is quackery.
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"Chiropractic, on the other hand, espouses all sorts of bullshit that is actually physically harmful."
I'm not a chiropractor but I did take a home course on chiropractic. It was nonsense but probably seemed less so back when the system was created. The idea is just that the vertebrae can get bound, will when given the correct counter pressure snap back in place and that they can when out of place induce pressure that distorts signaling throughout the body. Since the nerves reach and can stimulate most any r
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I used to do stroke research. One thing we saw a disturbing amount was young people, children in some cases, who had strokes due to dissections in their vertebral arteries. A suspicious number had recently been to chiropractors for neck manipulations. Not enough to prove a connection, but enough that the procedure wouldn't have a hope in hell of being approved, or continuing to be used, if it were subject to normal medical regulations.
Chiropractors were *extremely* hostile to the idea that anything they do
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"I used to do stroke research. One thing we saw a disturbing amount was young people, children in some cases, who had strokes due to dissections in their vertebral arteries."
That's pretty interesting. A chiropractor once said doing my own "corrections" was fine but strongly advised me to stop doing any corrections on my neck. Maybe that had something to do with it.
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Probably.
There's plenty of stuff about neck manipulation and stroke if you google "chiropractic stroke". The evidence has strengthened since I was in the field. For example: https://www.ncbi.nlm.nih.gov/p... [nih.gov]
The bigger point is that there is no such thing as a perfectly safe intervention. Everything has risks and sometimes they're subtle and unexpected. Paediatricians killed a bunch of kids and injured a lot more by recommending for years that babies and toddlers not be exposed to peanuts. Seems sensible, bu
Re: Nuclear Propulsion = Radiation Death Chamber (Score:1)
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Nearly all chiropracters that I have seen are quakes
I feel like I am not part of in-joke here. Someone else appeared to have misspelled 'quack' as 'quake' and it has been repeated by a number of other people... the only thing I am seeing is IDKFA.
what could possibly go wrong? (Score:2)
What sort of nuclear propulsion (Score:3, Interesting)
Is this an Orion type thing (propelled by nuclear explosions) or just a nuke heated conventional propellant (like water or ammonia or 'single-H' [see RAH books]
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you should read the story at ars
[*snicker*] You must be new. :-)
But noting (a) that I actually did read TFA (sigh).
nuke heated hydrogen fuel
and (b) Editors should have included that in TFS.
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"I actually did read TFA"
A formal procedure to revoke your Slashdot participation card has been initiated. If I were you I'd be seriously alarmed for the next couple decades while they consider adding a digit to your UID.
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>and (b) Editors should have included that in TFS.
[*snicker*] You must be new. :-) :)
hawk
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Touché. :-)
Re:What sort of nuclear propulsion (Score:5, Informative)
...you should read the story at ars - nuke heated hydrogen fuel...
Interestingly, the hydrogen propellant is the key part of these nuclear rockets.
They go faster not because nuclear is more powerful, but because the exhaust (hydrogen) is so much lighter.
At the same temperature, a lighter gas moves faster, thus giving a bigger push per kg of propellant. (specific impulse).
Cryogenic hydrogen is bulky and hard to store for long periods, so I had wondered if a nuclear rocket could fill its tanks with water, and blast steam out the back, as the space shuttle and other hydolox rockets do. That can be found on Mars or the lunar poles.
But it turns out that a nuclear-water rocket is slower than a chemical rocket, due to temperature limits. Hydrogen exhaust is the only thing that makes them viable.
(if I understand correctly? And not to be confused with a nuclear salt-water rocket.)
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Cryogenic hydrogen is bulky and hard to store for long periods,
That is not true since decades.
.
Re:What sort of nuclear propulsion (Score:5, Informative)
The latter. We know it works, see NERVA. https://en.wikipedia.org/wiki/... [wikipedia.org] President Nixon cancelled it only because he wanted revenge on Senators Marget Chase Smith and Clinton Anderson.
I knew it...! (Score:1)
I forget, is nuclear the first or second age in Starships Unlimited?
About time (Score:2)
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It's better than a chemical rocket, but not infinitely so. It would still be a very long trip.
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Nukes don't change the basic facts of space propulsion. There's no way to get delta-v other than tossing reaction mass out the vehicle. Nuclear power may make the reaction mass more efficient, but you still can only carry a finite amount and even with nuclear power you run out all too quickly if you try to do things in a hurry.
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Re: About time (Score:2)
Google Bussard ramjet.
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Wasn't the Bussard ramjet rejected as feasible, in part because of the technology requirements of producing the EM field, and in part because free hydrogen densities are lower than thought at the time.
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For one to collect useful amounts of hydrogen, it would have to have an incredibly strong magnetic field. Even if the technology to create such a field existed and didn't consume more energy than it collected, it would be extremely hazardous to the crew.
I seem to recall Larry Niven had them in some of his Known Space novels, and the magnetic field was a constant hazard. The Star Trek ones are even more hand-wavy.
Re: About time (Score:2)
eh? loop of wire can make propulsion from solar wind. solar sails are a thing too. Shining laser out back can make propulsion too, 300 MW beam gives 1 newton of thrust.
Have to toss mass my ass...
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They stop doing this because things we try to send to space blow up from time-to-time and if a craft with this sort of rocket on it blew up it would basically be a dirty bomb. I'm in Texas so as long as they continue to launch these in FL I feel pretty good about it.
Re: About time (Score:2)
no, reactor before first time going critical isn't any kind of dirty bomb. You have irrational nooquoolar phobia.
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The fuel is radioactive,
radioactive material + explosion to spread it around = dirty bomb.
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The fuel is radioactive,
The fuel is uranium.
radioactive material + explosion to spread it around = dirty bomb.
Uranium is a naturally occurring element. It is radioactive but minimally so. Spread that uranium around and it is not a dirty bomb, it is returning the uranium back to where it came from.
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the fuel before going critical first time emits alphas, which your skin could stop. I have some uranium in the file cabinet next to me, zero particles from it are hitting me or anyone else, because the steel of the file cabinet stops them... of course, so would a sheet of paper.
You have a problem, you see the word "radioactive" and your eyes spin in circles and a little cuckoo clock bird comes out of your forehead. But really there are many kinds and intensities of radioactivity. The potatoes in your ki
Because... you know... (Score:1)
...what could happen if they hack the object and throw them to Earth... with a nuclear reactor in it...
Re: Because... you know... (Score:1)
Legacy tech, maybe??? (Score:1)
Project Orion for the WIN!!!!
Four years from now? (Score:2)
NUclear or UNclear - it's neither (Score:1)
Elon Musk is a moron (see e.g. Twitter) but he did say it rather well, as does Newton's third law.
There's nothing "nuclear" here about propulsion. it's just how they get nuclear-fission energy
to the fuel.
A true nuclear-propulsion method would involve some nuclear reaction that leads to energy
released that would propel the spacecraft. Musk says that won't happen, and I suspect that
absent some new way of subatomic reactions he's right. Sorry to say...
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Elon Musk is a moron (see e.g. Twitter) but he did say it rather well, as does Newton's third law.
Newton was even crazier than Musk. Still a genius. ...
There's nothing "nuclear" here about propulsion. it's just how they get nuclear-fission energy
to the fuel.
A true nuclear-propulsion method would involve some nuclear reaction that leads to energy
released that would propel the spacecraft.
What, even an ion drive not "nuclear" enough for you? An engine emitting pure EM or other energy, like a big laser, would have awesome specific impulse - if you could ever get sufficient thrust. But to say that is the only "true nuclear propulsion" is ... I'm looking for another word ... nah, "moronic".
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I'm guessing we're both on the same side here... hopefully there will be such a drive.
OTOH I'm against false reporting and making up stuff.... so UNTIL we have such a drive... no more.
E
How about nuclear power plants instead? (Score:1)
We can't have nuclear power plants because they're too expensive. Isn't this going to cost way more? Now not only do you have to secure it to survive space travel, it's spending its time on land being manufactured and stored.
But somehow that's totally fine. We can't build nuclear power plants safe enough, but somehow when you strap it to a rocket and blast it off into space, it's different.
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It's not like we've not designed and tested putting nuclear devices on rockets before...
They launched nuclear powered devices in the past. This is just another one. The big cost to earth power plants are because it's on earth for it's duration and people don't like such a thing going wrong in their backyard.
Once in space, you only have to worry it'll bump into an alien and cause a war.
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Nope, nope and nope.
This will be a reactor of a few kilowatts of power, very tiny and useless for power plant on Earth. Power plants on Earth have reactors in gigawatt range, cost billions of dollars, have order of a million times more output than this puny nuclear bottle rocket.
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and before reactor is made critical first time in space, fuel is just inert metal making alpha particles your skin could stop. if it falls to earth, no big deal.
Still a rocket (Score:1)
They are using a fuel that they expel at the back to propel the object forward. That's a rocket however or whatever you do to the fuel before it's ejected.