Russia planning nuclear-powered manned spaceship

Shielding?

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?

RE: Shielding?

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.

@Jason Togneri

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...

@Jason Trolli

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?

@BristolBachelor

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' [1], 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.

[1]The academic paper concerning this magnet is here: http://ams.cern.ch/AMS/Talks/AMS_paper_B-Blau.pdf

@frank ly

"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).

http://spaceplace.nasa.gov/en/kids/st8/thermal_loop/

http://www.qrg.northwestern.edu/projects/vss/docs/power/2-how-does-the-shunt-vent-heat-into-space.html

@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.

YES!

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!

Shielding

"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.

@ 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!