Technology, Science and the Environment.

[AmyLGK]

3 minutes ago, Foxdiamond said:

Crikey there are some really clever people on this forum!. Out of my depth on this topic. I'll contain myself to worrying about our back four

Working on solving the worlds energy crisis is a lot less stressful than supporting Leicester!!! Stupid football - I will of course be watching tonight - after all week saying I wasn't going to 

 

you would definitely get fusion - if you don't understand this then it means we as science communicators aren't doing a good enough job!! The stuff I said in this thread was assuming some knowledge of the reader. 

 

Basically - very small gas particles are forced together to make a bigger gas particle (actually - it makes helium...that gas people blow up party balloons with to make them float - very safe!) and another incredibly small particle called a neutron. This neutron, when its made, is travelling very VERY fast - so when it collides with the inner wall of the fusion device it heats up the wall!! That heat is enough to boil water, which produces steam, which will be used to turn a turbine and generate electricity! Snazzy 

[WigstonWanderer]

20 minutes ago, AmyLGK said:

haha fingers crossed we all will!! 

 

I lead a research group at a university to develop the fuel and the first wall (inner chamber wall) materials for the post ITER devices - like STEP and DEMO. Some of our projects are co-funded by UKAEA. Please see my twitter page (link below in my signature) for more information 

Must be fantastically exciting times for you and your colleagues. Good luck….. and hurry up 

[Foxdiamond]

2 minutes ago, AmyLGK said:

Working on solving the worlds energy crisis is a lot less stressful than supporting Leicester!!! Stupid football - I will of course be watching tonight - after all week saying I wasn't going to 

 

you would definitely get fusion - if you don't understand this then it means we as science communicators aren't doing a good enough job!! The stuff I said in this thread was assuming some knowledge of the reader. 

 

Basically - very small gas particles are forced together to make a bigger gas particle (actually - it makes helium...that gas people blow up party balloons with to make them float - very safe!) and another incredibly small particle called a neutron. This neutron, when its made, is travelling very VERY fast - so when it collides with the inner wall of the fusion device it heats up the wall!! That heat is enough to boil water, which produces steam, which will be used to turn a turbine and generate electricity! Snazzy 

Thanks for the info. Great this will be safe and clean. Let's hope LC win again before this is actually here!

[leicsmac]

5 minutes ago, AmyLGK said:

Working on solving the worlds energy crisis is a lot less stressful than supporting Leicester!!! Stupid football - I will of course be watching tonight - after all week saying I wasn't going to 

 

you would definitely get fusion - if you don't understand this then it means we as science communicators aren't doing a good enough job!! The stuff I said in this thread was assuming some knowledge of the reader. 

 

Basically - very small gas particles are forced together to make a bigger gas particle (actually - it makes helium...that gas people blow up party balloons with to make them float - very safe!) and another incredibly small particle called a neutron. This neutron, when its made, is travelling very VERY fast - so when it collides with the inner wall of the fusion device it heats up the wall!! That heat is enough to boil water, which produces steam, which will be used to turn a turbine and generate electricity! Snazzy 

And hydrogen fusion isn't the only possibility, either - there are other options too, but the engineering challenges for any one of them are vast.

[AmyLGK]

5 minutes ago, Zear0 said:

Appreciate sharing all this.  Out of personal professional curiosity, what are the main challenges you're having to overcome with the material selection?  Noting the fuel used and high temperatures is hydrogen embrittlement the main concern for operations, or is the environment adequately controlled that it's less of a problem?  Presume all materials (at that temperature no s*** springs to mind) are upper shelf materials so getting adequate material toughness for the thermal stress intensities is doable?  Last one (I promise), how damaging are the neutrons to the material, are we likely to get some massive toughness degradation through life or is not to bad?

 

Regards,

 

One of the design folk!

Oooh lots of awesome questions there!! 

 

So, thanks to the bad ass magnets, the incredibly hot plasma will (should) never hit the wall (sometimes you get essentially little solar flares that do interact with the wall - but the plasma physicists are working on stopping those) - so we're designing materials that maintain the required properties up to 1200 deg Celsius. 

 

Tungsten (W) and beryllium (Be) are the current first wall materials (that's what ITER will have and what JET tested for the first time ever in real life conditions recently).  

Be isn't particularly nice to handle and can be toxic and W becomes brittle after a certain level of radiation damage. Plus the surface of W erodes over time due to interactions with the plasma and can fall off contaminating the plasma, as well as trap tritium - which we really don't want to happen (its a) radioactive and b) there isn't much of it). The neutrons produced during fusion can cause the atoms that make up the first wall material to be knocked off where they want to be - much like playing pool on the nano scale - which changes the internal structure of that material which in turn, changes the properties of the material - including making it brittle. Those neutrons can also be absorbed by the atoms transforming them into something that is radioactive and decays releasing helium (an alpha particle) and hydrogen (a proton) - which leads to both helium and hydrogen embrittlement. So whilst W and Be do the job for now - we trying to find new materials that can do a better job in the future, and not become radioactive for very long! 

 

[AmyLGK]

7 minutes ago, leicsmac said:

And hydrogen fusion isn't the only possibility, either - there are other options too, but the engineering challenges for any one of them are vast.

Yes - it's my understanding (I'm not a plasma physicist though) that the ONLY fusion reaction we can actually achieve on Earth that will produce more energy than we put in is the D-T reaction. Most test devices have been using the D-D reaction to learn about how to confine plasmas, but to get a net gain in energy we need the D-T reaction (which is what JET is now doing). The sun fuses helium and hydrogen - I don't think we're able to achieve the required conditions here on Earth for that using any known technologies. 

[leicsmac]

1 minute ago, AmyLGK said:

Yes - it's my understanding (I'm not a plasma physicist though) that the ONLY fusion reaction we can actually achieve on Earth that will produce more energy than we put in is the D-T reaction. Most test devices have been using the D-D reaction to learn about how to confine plasmas, but to get a net gain in energy we need the D-T reaction (which is what JET is now doing). The sun fuses helium and hydrogen - I don't think we're able to achieve the required conditions here on Earth for that using any known technologies. 

That's my reading of it too - deuterium-tritium seems to be the most efficient in any case.

[SpacedX]

3 hours ago, AmyLGK said:

Yes - it's my understanding (I'm not a plasma physicist though) that the ONLY fusion reaction we can actually achieve on Earth that will produce more energy than we put in is the D-T reaction. Most test devices have been using the D-D reaction to learn about how to confine plasmas, but to get a net gain in energy we need the D-T reaction (which is what JET is now doing). The sun fuses helium and hydrogen - I don't think we're able to achieve the required conditions here on Earth for that using any known technologies. 

Fusion also has massive potential for rocket propulsion. Through magnetic confinement and a heating plant fueled with a mixture of helium-3 and as @leicsmac mentioned, deuterium you can generate a high velocity exhaust - super heated plasma/ion drive. This means we can reach previously unattainable speeds compared to chemical rockets and opens up the possibility of interstellar travel. An associated problem would be lifting the vehicle into orbit via a conventional rocket due to its weight. 

 

While the DT reaction is the most accessible in today's state of technology, it has two major drawbacks, particularly for manned space exploration. Tritium as a radioactive element means that the fusion reactions produce a flux of highly energetic neutrons from which humans and electronic equipment must be heavily shielded. The deuterium/helium-3 reaction that is planned for the direct fusion drive engine has neither of these limitations -  both elements are stable together with the reaction products, hydrogen and helium so surely no heavy shielding would be required for protection? 

Edited 10 February 2022 by Line-X

[WigstonWanderer]

12 minutes ago, Line-X said:

Fusion also has massive potential for rocket propulsion. Through magnetic confinement and a heating plant fueled with a mixture of helium-3 and as @leicsmac mentioned, deuterium you can generate a high velocity exhaust - super heated plasma/ion drive. This means we can reach previously unattainable speeds compared to chemical rockets and opens up the possibility of interstellar travel. An associated problem would be lifting the vehicle into orbit via a conventional rocket due to its weight. 

 

While the DT reaction is the most accessible in today's state of technology, it has two major drawbacks, particularly for manned space exploration. Tritium as a radioactive element means that the fusion reactions produce a flux of highly energetic neutrons from which humans and electronic equipment must be heavily shielded. The deuterium/helium-3 reaction that is planned for the direct fusion drive engine has neither of these limitations -  both elements are stable together with the reaction products, hydrogen and helium so surely no heavy shielding would be required for protection? 

I’ve always wondered whether very high speeds required for interstellar travel are really practical. Notwithstanding the possibility of some form of suspended animation, and with the nearest stars some 4 light years away, a space ship would need to attain a velocity of around 1/4 the speed of light to reach its target within 16 years.

 

Even if those sort of speeds are attainable, absent Star Trek style force fields/shielding, any tiny pieces of matter in the path would simply pass straight through the hull, possibly causing immense damage or death to occupants. What is the probability that such damage could be avoided over the duration of such a trip?

[The Bear]

15 minutes ago, WigstonWanderer said:

I’ve always wondered whether very high speeds required for interstellar travel are really practical. Notwithstanding the possibility of some form of suspended animation, and with the nearest stars some 4 light years away, a space ship would need to attain a velocity of around 1/4 the speed of light to reach its target within 16 years.

 

Even if those sort of speeds are attainable, absent Star Trek style force fields/shielding, any tiny pieces of matter in the path would simply pass straight through the hull, possibly causing immense damage or death to occupants. What is the probability that such damage could be avoided over the duration of such a trip?

We'll there are theories that as you approach relativistic speeds, then the time taken for the journey is a LOT shorter for the people in the spacecraft than for other observers. This is due to time/space dilation and is difficult to explain unless I find the article again. 

 

And if we were to perfect an Alcubierre Drive (Warp Drive) then nothing actually hits the spacecraft, it's moved out of the way by the warp bubble around it. At least so the theory goes. 

 

I think at the cutting edge of this sort of tech and research the effects aren't as simple as just light speed x distance = time taken, and our usual way of thinking is often too simplistic and not equipped for this sort of stuff. 

Edited 10 February 2022 by The Bear

[WigstonWanderer]

12 minutes ago, The Bear said:

We'll there are theories that as you approach relativistic speeds, then the time taken for the journey is a LOT shorter for the people in the spacecraft than for other observers. This is due to time/space dilation and is difficult to explain unless I find the article again. 

 

And if we were to perfect an Alcubierre Drive (Warp Drive) then nothing actually hits the spacecraft, it's moved out of the way by the warp bubble around it. At least so the theory goes. 

 

I think at the cutting edge of this sort of tech and research the effects aren't as simple as just light speed x distance = time taken. 

Yes I realise relativity plays a role, but won’t make that much difference at speeds up to 1/4 the speed of light. The relevant factor IIRC is the square root of 1 - v2/c2, so in this case square root of 15/16. To be honest I can’t recall exactly how it affects the traveller, but the point is it will still take a long time at anything other than a significant proportion of the speed of light, and this would cause the sort of potential impact problem I mentioned.

 

Of course, interstellar space is pretty empty, so perhaps the chances of a collision are vanishingly small, I don’t know.

 

As for warp drives, I suspect that these will remain the realm of science fiction unfortunately.

Edited 10 February 2022 by WigstonWanderer

[SpacedX]

10 minutes ago, WigstonWanderer said:

I’ve always wondered whether very high speeds required for interstellar travel are really practical. Notwithstanding the possibility of some form of suspended animation, and with the nearest stars some 4 light years away, a space ship would need to attain a velocity of around 1/4 the speed of light to reach its target within 16 years.

 

Even if those sort of speeds are attainable, absent Star Trek style force fields/shielding, any tiny pieces of matter in the path would simply pass straight through the hull, possibly causing immense damage or death to occupants. What is the probability that such damage could be avoided over the duration of such a trip?

Well deep/interstellar space is...just that. Very empty and very big.  Asteroids and even micrometeorides are common to a solar system due to the gravitational attraction of a star, Nonetheless The real problem when moving at velocities that are low percentages of the speed of light is as you suggest matter and dust. There was a proposed part of Project Daedalus in the 1970’s that looked at this. The craft would need some sort of bow wave shielding because you cannot realistically avoid it. 

 

Regarding human travel, perhaps our future colonisation lies in AI and motherships or arks containing cryogenically preserved genetic material? There are suggestions that in the interim the moon could become a repository. 

 

https://www.livescience.com/proposed-lunar-ark-for-biodiversity.html

[Foxdiamond]

4 minutes ago, Line-X said:

Well deep/interstellar space is...just that. Very empty and very big.  Asteroids and even micrometeorides are common to a solar system due to the gravitational attraction of a star, Nonetheless The real problem when moving at velocities that are low percentages of the speed of light is as you suggest matter and dust. There was a proposed part of Project Daedalus in the 1970’s that looked at this. The craft would need some sort of bow wave shielding because you cannot realistically avoid it. 

 

Regarding human travel, perhaps our future colonisation lies in AI and motherships or arks containing cryogenically preserved genetic material? There are suggestions that in the interim the moon could become a repository. 

 

https://www.livescience.com/proposed-lunar-ark-for-biodiversity.html

I would just be pleased if the buses turned up on time

[SpacedX]

Just now, Foxdiamond said:

I would just be pleased if the buses turned up on time

You wait a geological epoch for one Mothership and two come along at once. 

[Izzy]

31 minutes ago, The Bear said:

We'll there are theories that as you approach relativistic speeds, then the time taken for the journey is a LOT shorter for the people in the spacecraft than for other observers. This is due to time/space dilation and is difficult to explain unless I find the article again. 

 

And if we were to perfect an Alcubierre Drive (Warp Drive) then nothing actually hits the spacecraft, it's moved out of the way by the warp bubble around it. At least so the theory goes. 

 

I think at the cutting edge of this sort of tech and research the effects aren't as simple as just light speed x distance = time taken, and our usual way of thinking is often too simplistic and not equipped for this sort of stuff. 

It's not exactly rocket science though is it 

[String fellow]

5 hours ago, AmyLGK said:

Working on solving the worlds energy crisis is a lot less stressful than supporting Leicester!!! Stupid football - I will of course be watching tonight - after all week saying I wasn't going to 

 

you would definitely get fusion - if you don't understand this then it means we as science communicators aren't doing a good enough job!! The stuff I said in this thread was assuming some knowledge of the reader. 

 

Basically - very small gas particles are forced together to make a bigger gas particle (actually - it makes helium...that gas people blow up party balloons with to make them float - very safe!) and another incredibly small particle called a neutron. This neutron, when its made, is travelling very VERY fast - so when it collides with the inner wall of the fusion device it heats up the wall!! That heat is enough to boil water, which produces steam, which will be used to turn a turbine and generate electricity! Snazzy 

If I understand it correctly, that's one of the main disadvantages of D-T fusion. The energy is released mainly through neutrons. Since they aren't charged particles, the neutrons need to generate heat, to boil water, to produce steam, to produce high pressure, to drive turbines, to finally induce electricity in nearby coils. It's an incredibly inefficient way of converting the nuclear energy into electricity. Furthermore, the neutrons produce harmful ionising radiation, so suitable biological shielding is needed that will stand the test of time. If a workable fusion process could be divised so that charged particles such as protons are emitted instead, then the energy could be converted directly into electricity without all the intermediate stages. Apparently, aneutronic fusion requires more extreme conditions in which to operate than does the current D-T fusion being researched by JET.

[leicsmac]

5 hours ago, String fellow said:

If I understand it correctly, that's one of the main disadvantages of D-T fusion. The energy is released mainly through neutrons. Since they aren't charged particles, the neutrons need to generate heat, to boil water, to produce steam, to produce high pressure, to drive turbines, to finally induce electricity in nearby coils. It's an incredibly inefficient way of converting the nuclear energy into electricity. Furthermore, the neutrons produce harmful ionising radiation, so suitable biological shielding is needed that will stand the test of time. If a workable fusion process could be divised so that charged particles such as protons are emitted instead, then the energy could be converted directly into electricity without all the intermediate stages. Apparently, aneutronic fusion requires more extreme conditions in which to operate than does the current D-T fusion being researched by JET.

What you're describing here would be satisfied by Helium-3 fusion (in it's second or third generation, anyway). However, the temperatures and conditions needed to achieve that kind of fusion are much higher than the D-T fusion we're experimenting with right now, as you say.

[Jon the Hat]

This is like being at work where I can get my head round the mining equipment which makes big rocks smaller, but when it comes to the metallurgy / chemical stuff its just noise...

Edited 11 February 2022 by Jon the Hat

[SpacedX]

This thing packs twice the thrust of the Saturn V - which is insane.

 

https://www.bbc.co.uk/news/science-environment-60340092

[leicsmac]

1 hour ago, Line-X said:

This thing packs twice the thrust of the Saturn V - which is insane.

 

https://www.bbc.co.uk/news/science-environment-60340092

Hopefully it all works out well. It's long past time we got out there in numbers, and this time, don't stop.

[Zear0]

1 hour ago, Line-X said:

This thing packs twice the thrust of the Saturn V - which is insane.

 

https://www.bbc.co.uk/news/science-environment-60340092

As a mechanical engineer of 12 years I need to slap myself for saying this, but it looks so janky and flimsy that I'm always amazed to see it in action.  I can't wait to see the fully stacked version launch, as I struggle to appreciate the size of this thing due to the "wider" design geometry compared to other launch systems.

 

Huge credit and admiration for the teams for producing these things.  I remember when I first saw the Falcon 9 landing on the pad and barge it and was one of those rare moments where I was genuinely stunned at the technical competency of what I was seeing.  Hopefully Starship will do the same.

[SpacedX]

Just now, Zear0 said:

As a mechanical engineer of 12 years I need to slap myself for saying this, but it looks so janky and flimsy that I'm always amazed to see it in action. 

Lacking your technical insight I nonetheless have always thought the same. It reminds me of something out of the Eagle comic, an episode of Buck Rogers or a 1930s Flash Gordon film.

[leicsmac]

https://www.bbc.com/news/science-environment-60333422

 

"An unnatural shift in the atmosphere's chemical make-up resulted in the slow but irreversible onset of an ice age...the exact cause remains unknown, but probable explanations include failed terraforming attempts or even inter-planetary terrorism. Some of the more radical elements within the scientific community on *insert Planet name here* suggest that the dramatic climate shift may have been brought on by the unchecked emission of gaseous industrial by-product into the atmosphere of the planet known as "Sol 3". 

 

"...This view is confined to the scientific fringe, as it is unlikely that any race intelligent enough to achieve full industrialization would be stupid enough to accidentally wipe themselves out."

[leicsmac]

 

I hope I live long enough to see something like this happen.

[Carl the Llama]

Nick Clegg's doing alright for himself

https://www.bbc.co.uk/news/uk-60410636