Science Fiction Rut Season?

Ray McCarthy said:

Artificial Intelligence
== I think it's fantasy, but people that know less about Computers and Programming think it may be possible. These can be inside or remotely control Mechanical Avatars if you want.

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It may not be impossible but I think it will be a much more difficult than is usually implied.

Electronic computers have only existed for 69 years. Who knows what another 500 years of development will do?

psik

Brian Turner said:

three laws of robotics, then is it really worth bothering to read the Robot series of stories

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The three laws (or four) are really unimportant. The point was having "set up a system" was then to have fun breaking it. Most of the Robot stories are about people's preconceptions. They are also a little like "locked room" detective stories. Asimov wrote some non-SF detective short stories too. So the WHOLE POINT of reading the Robot Stories is to already know the "so called" laws. Which is why they are usually printed at the start, or characters explain them. Another time I'll rant about the Zeroth Law and and the later Foundation books.

Ray McCarthy said:

So I'd split Hard SF to
Future on Earth
Space Travel
Artificial Intelligence
CyberBiology
A story can of course mix and match all four of these so categorising is nearly impossible.

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It's an interesting breakdown of hard SF. I would add Genetics/Biomanipulation as a 5th subgenre.

Re Space Travel - nuclear fusion is currently anticipated to be available within 20 years as a lorry-sized power plant.

Re Artificial Intelligence - this phrase was coined in 1956 to mean computers emulating the human brain. However, those in the field have long since agreed that the research and results to date have diverged away from this aim to computers being able to store easily accessible knowledge (think bank accounts), evaluate predictions (think weather forecasts) and more precise machine control in more varied conditions (think driverless car).

Serendipity said:

I would add Genetics/Biomanipulation as a 5th subgenre.

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I thought I had it as a sub "Future on Earth" thing. Where you can stick in Nanotech too.

Yes I did

Ray McCarthy said:

Future on Earth
== Various kinds, i.e. post apocalyptic, Machine ruled single government, near or far future, effect of say a SINGLE invention, more advanced Genetic Engineering and/or Nanotechnology

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Of course feel free to make Genetics and Nanotech 5th & 6th rather than sub genres of Future Earth.

But really many books won't fit neatly defined sub genre division. I feel I'm beginning to sound like "Thursday Next".

Serendipity said:

Re Space Travel - nuclear fusion is currently anticipated to be available within 20 years as a lorry-sized power plant.

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That is only the reaction vessel! It maybe could be 5 to 10 years. As I formerly designed Industrial Controllers for Power stations, I can tell you the heat exchangers, shielding, steam turbine and Generator is very much larger. They do talk about fitting it all inside a C5 sized plane, but that seems slightly unlikely for 100MW. Certainly if you want any cargo.

Serendipity said:

Artificial Intelligence - this phrase was coined in 1956 to mean computers emulating the human brain. However, those in the field have long since agreed that the research and results to date have diverged away from this aim

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In fact actually nothing like any reasonable conception of Intelligence. Humpty Dumpty: Words mean whatever I want them to mean. We are MUCH further away from real AI now than it seemed in we were in late 1950s. OTOH, fusion does seem slightly closer.

Ray McCarthy said:

That is only the reaction vessel! It maybe could be 5 to 10 years. As I formerly designed Industrial Controllers for Power stations, I can tell you the heat exchangers, shielding, steam turbine and Generator is very much larger. They do talk about fitting it all inside a C5 sized plane, but that seems slightly unlikely for 100MW. Certainly if you want any cargo.

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I know it might seem like a hobbyhorse of mine, but focus fusion appears to be closer to success than any other approach. And, according to publicly available material, the likely minimum size of a unit would be around 5MW - which is about 7000HP, suitable for locomotives and small ships. And the reactor would be about the size of a large fridge and cost about $500,000; this is at the start, and we all know things get cheaper with economies of scale.

The group doing the research appears to need about $1M for proof of concept, and around $50M for development into a working reactor if it pans out. Small change, compared to the tens of billions so far spent on tokamaks.

And finally - The way that focus fusion works (assuming it does) is such that turning a reactor into a reaction engine would be trivially easy. (Most of the energy of the reaction comes out as a fairly tight beam of alpha particles.) Fusion rockets give us the solar system.

All for 50 million dollars. And Bill Gates has spent 500 times that much on trying to solve the problems of Africa.

Where fusion is concerned, I don't really see it making much difference to space travel. Sure it will allow access to greater areas of the solar system but that's about it (unless we build an ark) To go further into space in a manned vehicle we need to open up new areas of science (eg faster than light travel, folding space etc).

To me, the question is not how much energy we can produce or prolong but how we apply that energy.

Foxbat - It's often been said that with chemical propulsion, the best we are ever going to do is cislunar space - and that will remain difficult and expensive. The reason is simply the limit on exhaust velocity, imposed by the limited energy of chemical reactions.

Anything that increases exhaust velocity (and thus decreases reaction mass required for a given delta-v) or eliminates the need for it altogether (beanstalks, solar sails) makes space travel more practical. But here we come to another problem; most of the existing or upcoming high-velocity techniques are low-thrust compared to the mass of the ship. (Ion drives, mass drivers, plasma drives) And this is because they need serious amounts of power, the only sources of which so far are solar panels and fission reactors, both of which are very massive for a given output.

Fusion drives offer the possibility of reasonably high thrust and high exhaust velocity in combination. (I don't think, BTW, that anyone is suggesting a fusion drive would be suitable for launching; the thrust is likely to be a maximum of maybe a tenth of a gravity, and of course there is a significant side-effects problem. Fusion drive exhaust is nasty stuff!)

The only other mooted high-thrust, high-efficiency drive is also nuclear-powered and is probably practical if anyone could get around the counter-intuitiveness. And that's a serious problem; Orion drives are a cool idea, but would you want to be a passenger on a ship that propels itself with nuclear bombs? BTW, ground launch with Orion is probably possible - but I have a strange idea that Greenpeace might object.

We can do the Solar system with Fission power. But for anything else Fusion may be needed.

For the moment, unless the engineering an materials issues are solved for a space elevator, the only way to get stuff into orbit is chemical. You would only want one emergency launch of Orion drive from ground, ever.

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Ray McCarthy said:

We can do the Solar system with Fission power. But for anything else Fusion may be needed.

For the moment, unless the engineering an materials issues are solved for a space elevator, the only way to get stuff into orbit is chemical. You would only want one emergency launch of Orion drive from ground, ever.

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Actually, I disagree about the launching part of your post. There are a few other ideas that might work; laser launching and maglev launch from very high altitude are two of the possibilities. (The latter probably involving chains of huge aerostats holding up an EM cannon's rings at maybe 30km up.)

Maybe some day:
Laser: very low masses
EM catapult. Definitely fiction today. May never work. Acceleration probably too great for anything other than components. Getting it high enough so air resistance isn't an issue is a huge problem. Practical for Moon, (See "The Moon is a Harsh Mistress") as there is no atmosphere.
Space Elevator: significant mass and probably will work

I did say For the moment
A High Altitude Balloon launch or Aircraft launch actually doesn't save much rocket fuel.

There may be something else we haven't thought of.
Is mining and fabrication of space ships on the Moon practical so we only have to lift people (and initial stuff to start moon base)?

Ray McCarthy said:

I did say For the moment
A High Altitude Balloon launch or Aircraft launch actually doesn't save much rocket fuel.

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Agreed about for the moment in the sense that we don't actually have it ready to take off. But Skylon actually breathes in air to use its oxygen as fuel until it reaches Mach 5.14 (28.5km), before switching to be a rocket. This saves carrying a heck of a lot of fuel. It is due to be available from about 2022 onwards.