Russian space chiefs are considering plans for a manned spacecraft with a nuclear powerplant aboard, according to reports. Indications are that the nuclear kit would provide electrical power rather than being used directly for propulsion. RIA Novosti reports that Anatoly Perminov, chief of the Russian space agency Roscosmos, …
Time for ESA to embrace Russia?
If the Russians have got the technology, and only require relatively small amounts of cash, then I reckon that ESA should look to partner them on this. This would give ESA's manned program some future direction beyond LEO and spur NASA (the US government really) into serious action. Then at least some progress from LEO can be made.
As a by-product, high-tech cooperation like this can often lead to better relations at ground level as well.
Only one way forward...
...the entirely bat-shit crazy, 'go to Saturn in the Albert Hall on the back of an H-bomb' - Project Orion. Brought to you in 1950s tail-fin and bobby socks glory by the company with the coolest name in the history of bonkerdom: General Atomics.
It's what Gerry Anderson would want us to do.
Even without cosmic radiation to worry about, there's going to have to be some pretty heavy-duty shielding to protect the astro/cosmonauts against the reactor's own emissions, something that's going to be expensive to push into orbit.
I'm intrigued by the propulsion systems they're considering, if they're looking beyond chemical. A pulse-nuke drive is going to be far too "dirty" for orbital insertion, so what are they thinking about? Anyone any ideas?
VASIMR, an electrically run plasma rocket system that recently demonstrated a full power run on the ground and is scheduled for a space test attached to the ISS. The performance predictions for this engine are remarkable but it does require substantial amounts of electricity to run, more than would practical using solar power for deep space missions - even for Mars. A nuke would be the ideal way to power the drive.
I don´t think that magnetic sheilding will have much effect on galactic cosmic radiation. It will have zero (approx) effect on the neutral stuff, and the high energy charged stuff will just hit a different part of your body after the magnets stear it a bit. One of the most powerful superconducting magnets ever is going to fly to the ISS, and it´s only expected to stear particles so you identify their mass and charge.
I´d guess that any radiation leakage from the reactor would be fairly low energy and easier to shield. Plus the nuclear power plant is normally put on the end of a long boom away from anything sensitive (in this case including fleshies).
As for propulsion; chemical is the only way to get into orbit. After that I´d guess that they´re looking at ion drive. The Russians have been using this tech in space for some time, even before ESA´s SMART1 and the more recent GOCHE. However to make a difference on a big craft, you would need LOADS and LOADS of power...
@ Jon Green / Shielding
Wrong! Several things. First of which is that obviously, shielding would be minimal. On Earth, you have to have basically a complete sphere around the reactor core to shield emissions from the environment. In space, you only need a thin wedge of shielding directly between the reactor and the crew quarters. Anywhere else, the core just radiates into space and won't affect anything. Getting the bugger into orbit in the first place is your only real problem - but heck, fly it up in sections and fire it up in space.
Second thing, the problem on Earth is coolant. In space, you have the ultimate coolant - absolute-zero hard vacuum. Problem more or less solved. (Also for computing, maybe - powerful computers generate lots of heat, so why not install them near the bulkheads in a sealed section and wire them with heatpipes connected to something transmitting absolute zero from the outside? In fact, is there any reason why radiation-shielded computers couldn't exist directly in vacuum?)
Actually, in all of this, the problems come down to the same things: getting a payload out of the gravity well in the first place, getting funding to do so, and getting politicians to not fuck it all up. Sort those, and the rest is relatively easy.
I could be wrong, but I'd have thought that a hard vacum is a pretty useless coolant - you have to rely purely on radation rather than convection or conduction. Isn't that why space craft have such massive cooling problems...
Unless you've noticed many submarine or aircraft-carrier navy personnel growing extra heads, I'd say shielding a mobile reactor is a solved problem, yeah?
It's also worth going back to the film (and book) of 2001. Arthur C Clarke couldn't write for crap, but he knew his science. His long-mission ships had a crew quarter at one end, the reactor and propulsion system at the other, and a half-mile of struts between them. On Earth you'd need massive girders to hold something like that together, but in space there's little in the way of external forces, and if you're using a VASIMR drive there isn't actually very much acceleration either, so you can get away with pretty flimsy struts.
I can't even be arsed to tear you to shreds on so many basic errors in your misunderstanding of the principles of temperature and radiation/conduction of thermal energy, and your misapplication of this at the working temperatures of modern CPUs and nuclear reactors
Provided the thing never comes back to earth ....
I don't see a problem with building a reactor in orbit and then sending it off into space. Enriched Uranium fuel rods aren't desperately radioactive, an accident while they were being transported up into orbit would not be very serious. It's only after the reactor goes critical, that you really don't want any chance of it re-entering Earth's atmosphere.
As was pointed out above, a space reactor needs very little shielding. For a true low-G spacecraft, you can put the reactor a long way from the rest of the space-ship, connected via a lightweight structure rated for milli (or micro?)-G forces only. Neutrons heading out into space are harmless (half-life 15 minutes after which they'll just join the other protons in the solar wind), and inverse squares will do a lot to reduce the neutron flux that you'll have to shield the crew quarters against.
It's just occurred to me that if you put a lump of Uranium (the reactor core) between the crew quarters and the sun, that would be useful shielding against solar storms as well!
@Jason Togneri re.vacuum stuff
A vacuum doesn't have a temperature (think about it). There isn't anything there to transfer thermal energy to (think about it). The only way to get rid of heat in space is to radiate it away (think about it) - unless you use a disposable fluid that you piss away in a very hot stream, and how long will that last for?
Firstly, you are correct in your assertion that magnetic shielding would have no effect on neutral particles. However, these also don't have very high energies like charged 'cosmic ray' particles, which get accelerated by the magnetic fields of things like spinning black holes and supernovae.
In fact, the Earth's magnetic field also has no effect on such particles, the only defence being atmosphere. I really don't think such particles are a problem.
Secondly, the AMS-02 superconducting magnet on the ISS is only 'the first large superconducting magnet to be used in space' , which has a core magnetic field of 0.87 Tesla. This is less powerful than the magnet used in a modern MRI scanner, for instance. Furthermore, this won't be powered by a nuclear reactor, since there isn't one on the ISS (unless that's something else the Russians aren't telling us about), which could pump a lot more juice through it. In a superconducting magnet, the field strength is proprtional to the amount of power put into it, without heat losses (hence superconducting).
Finally, you claim that diverting the charged particles with a magnetic field would be pointless because, 'the magnets stear it a bit'. This is the whole point of magnetic shielding, and is pretty much exactly what the Earth's magnetic field manages (quite successfully) to do. All the Charged particles get diverted to the poles of the magnet (on Earth, this causes the polar aurorae). Any half-competent spacecraft designer would make sure that they didn't put the crew quarters there. In fact, they could probably do a bit of cunning design and use the magnetic shielding to eject the charged radiation from the reactor along the same axis, cutting down on heavy radiation shielding, since then they'd only really have to worry about gamma radiation.
The academic paper concerning this magnet is here: http://ams.cern.ch/AMS/Talks/AMS_paper_B-Blau.pdf
"The only way to get rid of heat in space is to radiate it away (think about it) - unless you use a disposable fluid that you piss away in a very hot stream, and how long will that last for?"
Until the beer runs out. And let's face it, you'll want to be coming back by then anyway.
@frank ly @zedee
I really wish you arm chair experts would stop commenting on stuff you obviously don't understand, or at the very least go and get something that resembles a physics education.
@frank ly - do yourself a favour and go and understand what a vacuum actually is, then decide how the Sun heats the earth through the vacuum of space with your "disposible" fluid. (Radiation is the answer you're looking for, hence the reason the "fluid" is called electromagnetic radiation).
"Second thing, the problem on Earth is coolant. In space, you have the ultimate coolant - absolute-zero hard vacuum."
There's a major problem with that statement.
You can classically cool things in three ways. Convection, conduction and radiation (there are some more esoteric ways, but these are the practical, engineering ones). Of those, both convection and conduction require physical contact with matter - in fact convection requires conduction, it's just that the process moves the coolant fluid, which can also be done by pumping and so on.
In space, that leaves you with radiation alone - basically black body radiation which, for a given temperature, emits energy at a fixed rate. That's it - the only form of cooling you have. It matters not a jot that the virtually empty space around you is at near absolute zero - if the few particles in space were at 1,000K it would make no difference to the rate of cooling (well there is an integration to infinity thing, but leave that out for the moment).
One of the problems of space travel is cooling high output systems (chemical rockets get round it by chucking the hot test stuff out the back). The only two ways you can increase cooling capability is by increasing the surface area or running at a hotter temperature. The power dissipated goes to the 4th power of temperature, so there is a very steep curve. A metre square metal plate glowing to red-heat will radiate quite a lot of energy, but if you start trying to run reactors generating 10s of megawatts then that's going to require a large surface area. If you need to cool things down to the temperature required for semi-conductors then that area will increase disproportionately due to that 4th power law.
Cooling a nuclear powered rocket is a serious engineering challenge, not least because space is a vacuum. The numbers can probably be made to work, but the termperature of a near vacuum is absolutely no help at all.
@zedee (@Munchausenn's proxy)
It makes you want to weep. Then you think "why should I bother and why should I give a damn?"
(I read that alcohol is not allowed on space missions, so I'm not going there!)
This idea brought to you by...
The makers of Chernobyl. Yes, when it comes to nuclear reactor design and operation, the Russians are the first people I call -- for containment and clean-up.
Mine's the one with the lead-lined codpiece.
ignoring the technical stuff above...
... anyone else think Russia is several steps ahead of the rest of the world and where we should all be aiming at?
We (ESA) have got nothing truely to speak of besides our token part in the ISS. The US are about to take a giant leap (backwards) for mankind by ditching the shuttle and going back to a rocket which is soooo 1970s.
Project Orion / NERVA (call it whatever you want) is go!
Let's hope they give it a suitably cool sounding Russian name with the obligatory black paint scheme and imperial red star. NATO will, of course, need to give a reporting codename...
Beer, for Mike Richards, for that description!
"If the Russians have got the technology"
They;va had it for decades just like the rest of the world, in fact the russian version of the tech involved is one of the world's largest supply of illicit plutonium.
They're called radioisotope thermoelectric generators - nasa use them, russia uses them, and no doubt the ESA has at least experimented with them.
They are most definitely not new, what this article seems to be refering to by the text and hence not newsworthy.
"some pretty heavy-duty shielding to protect the astro/cosmonauts against the reactor's own emissions, something that's going to be expensive to push into orbit."
Less than people think. At the Helsinki university of technology, they used to give new pupils tours of the reactor lab, where we could peer at the core of the working research reactor through a layer of water (about 2 meters IIRC) and see the blue Cerenkov radiation. So a tank of water a few meters long between the reactor and crew quarters would probably be enough, even if they were close. A real spaceship would likely have a lot of other stuff (long struts were mentioned in other posts, why not also use propellant tanks as shields) between the reactor and crew. Probably the real rocket scientists in Russia can think of lots of more sophisticated solutions.
Having a powerful nuclear reactor means you can stop thinking about the thing as a an aeroplane and more as a ship. Less weight limits.
The amount and type of shielding depends on the type of ionising radiation is being talked about and, to a lesser extent, its intensity. As that was Cerenkov radiation, then that was occuring because of charged particles (travelling faster then the speed of light in the medium in question - in this case water. Charged particles are highly ionising, but generally easily stopped. Neutrons have relatively limited penetration power.
However, the same cannot be said of gamma rays - they are much less ionising than charge particles, which is essentially because they penetrate much further. Of course that makes them less damaging, but there are limits. If the reaction generations large amounts of gamma rays then it will need fairly thick shielding (depending on the energy of the photons) - far more than required for absorbing neutrons, beta or alpha particles for instance. The important thing is the amount of mass - denser materials are more compact, but their use won't decrease the total mass requirement by that much. The type of fission reactor used to produce electric power generates rather a lot of gamma rays so shielding is fairly thick, but the mass is quite useful for containment.
Total mass isn't too much of an issue with nuclear powered ships, submarines or power stations, but it is for slinging things into orbit. Of course this is all fantasy stuff - if we could produce nuclear powered rockets, then we'd have the technology for moon bases.
However, if you are on an inter-planetary flight you'd probably have far more to fear from being caught in a solar storm. The charged particles from that would be really dangerous - it's a technically far more difficult challenge than shilding a mere fission reactor.
@ all those above
Yes yes, poorly phrased. I was of course referring to a heatpipe-type closed loop arrangement with coolant (isn't it ammonia that they use on the ISS as coolant fluid?) going out and back in again. I apologise that my throwaway comments caused such apoplepsy amongst you.
Shielding in space
If you've got a bigass nuclear reactor to provide power, why not use some more of that power to set up a powerful electric field at the back of the reactor? Any alpha or beta radiation pointing backwards could be accelerated- providing an (admittedly pretty tiny) amount of thrust in the style of the VASIMR. Pretty small advantage, but over a month-long flight to Mars it'd have a measurable effect.
Also, if you're wanting an effective radiator in space, couldn't you have a simple arrangement where a heat carrier is pumped between two sheets of aluminium (or even better Gold) foil (welded at points to provide a "pipework" to make sure the heat carrier spends ages on the radiator)? I mean it's not like you're restricted for space, so you could get a huge surface area to radiate from.
A flimsy support structure between the reactor and the crew quarters probably wouldn't be a good idea if you're planning on atmospheric braking when you get to Mars. To do a proper exploration ship you'd need either another load of chemical rockets to launch it again or a lighter lander of some sort. Would it be possible to use the already-present (on Mars) frozen CO2 + a smaller (probably nuclear) heat source to create pressurised gaseous CO2 to use as a propellant? NASA suggested a similar thing could be used to make a hover-sled for use on the martian surface a few years ago.
I wonder how long until someone builds the first nuclear + ultra-high-power VASIMR + landing-craft + decent interior Star Trek/Battlestar style vessel? Obviously without the FTL capabilities!
East Or West, Up Is Best
@ frank ly
"A vacuum doesn't have a temperature" -
Point of view of a vacuum?
@ Martin Nicholls
"one of the world's largest supply of illicit plutonium" -
Oops.. how much illicit plutonium does man suppose to be necessary to get lifted to the orbit?
As for the gear, I'd suppose that it will be a plasma-driven one, with a relatively compact nuclear power source. A student recently made a battery demo from a TV antenna, a magnet and two empty Coke cans, scientists were shocked. Roskosmos seemed interested... though, my personal point of view that international affair would be not just a vanity fair as anybody may believe it to be. All above the sky is international, especially if the oils go down.
@ Will 22
"Let's hope they give it a suitably cool sounding Russian name with the obligatory black paint scheme and imperial red star. NATO will, of course, need to give a reporting codename..." -
Name is hardly less serious item than a gear. Must be an international name contest or something, I talked on the oil already...
Though, for wider mentioning in English-speaking Google, a NASA reporting codename may appear there, with the obligatory imperial red star, and you may choose the black paint.
A good move
If they really want to "maintain a competitive edge in the space race", this is a good direction to take, since they have little to worry about in the way of competition from the west - public opinion in the US and Europe has and will continue to prevent any serious moves in this direction. So we'll continue to poke along with our chemical or solar or itty-bitty-RTG powered spacecraft, while Russia has the opportunity to take the large-scale/high-performance arena for itself (unless the Chinese decide to get involved). That it would decide to spend the rubles to exploit that opportunity is probably too much to hope for.
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