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Comment lets stamp out every last tourist (Score 1) 220

Right. Because there was still that one guy who kept coming back to the US for a holiday. Let's make sure that guy never comes back. He's a nuisance and takes away airline seats from everyone else who has no choice but to go to the US for some reason. Airline seats are scarce and precious. Let's keep them as empty as possible. To be fair I guess it does make their jobs easier to keep tourists away.

Comment Re:Holy shitballs, all the sci-fi books were right (Score 1) 347

It seems to me, though, that setting up a "spacecraft manufacturing facility" (including materials production, fabrication and assembly) on the Moon is a project of many decades.

Yes of course. I'd assume at least a 100-150 year minimum to properly set up such a facility complete with lunar mining, lunar nuclear reactors, probably earth moving equipment manufacturing, smelting and casting and machining. There is so much that would be either necessary or desirable that will take a long long time to get going.

As far as asteroids go I don't think an Orion ship would be able to change the course of any even moderately sized one. Or were you thinking as a means of getting some humans off planet to prevent the extinction of our species? In any case a pulsed nuclear ship big enough to do either of those missions would be prohibitively expensive.

Comment Re:If You're not rich, have a bright future! (Score 1) 367

Instead there are going to be general purpose AIs

In 20 years? We are nowhere near that now. There would have to be fundamental breakthroughs in AI and probably in neuroscience to have even the slightest chance of that being true. A more realistic time frame would be 2000+ years from now. Millennia rather than decades.

Also if we ever do reach self-aware general AI they will be entities with rights. We could not just make them work without compensating them. That would be slavery. They would become just like mechanical people with some advantages and some disadvantages over the rest of us bio-humans. And they would surely expect to get paid at least as much as us. Maybe more if they have greater strength and stamina and are willing to do boring and physically demanding work. Probably robotics companies will try to give their machines just enough intelligence to follow basic commands but no more. That means any intellectually demanding jobs will remain quite safe.

Companies won't be hiring new workers

I would think robotics companies would be hiring a lot of new workers if what you are saying ever comes to pass. Building millions or billions of sophisticated general purpose robots even without advanced AI requires a lot of humans, both smart and not so smart.

they'll be buying new machines

From whom exactly and how will those companies build those robots? With magic? They will need people for that. Even if they can build the robots with other robots they will at some point need humans to build the robots that make the robots that make the robots... Maybe eventually only the premium most advanced models will require humans to build them, but that point is probably at least 1000 years away.

Low skill jobs the world over are particularly vulnerable this time around.

Well all I can say is those robots better be very cheap indeed because labor in the country where I am living now can be had for as little as $5-$7 per day.

In any case it is called progress. If we followed your logic we'd all still be riding in horse-drawn carriages to get around. Of course horseshoe manufacturers and hay growers would have loved that.

Comment Re:Holy shitballs, all the sci-fi books were right (Score 1) 347

One of the points of Orion was that it provided more than enough power to lift heavy vehicles from Earth's surface.

I never considered that to be one of its primary advantages. It's just too dirty. Not sustainable for multiple launches. It's primary advantage is that it can carry enough fuel with it to actually go somewhere interesting in a reasonable time period. Most propulsion systems cannot. We could just just set up a spacecraft manufacturing facility on the moon and launch from there.

Comment Re:interstellar mission (Score 1) 347

I''ll reiterate that quoting a "speed in which a technology can reach" is meaningless.

Excellent! so then there is no problem getting close to the speed of light via fission fragment propulsion then? Or were there practical engineering limitations you are ignoring with that statement? To me the speed reachable by a spacecraft that we could actually build (budgetary issues aside) today is very much the whole point of the exercise. In theory you probably could build an antimatter rocket with just a few atoms of antimatter, but it would not do very much now would it? And yet in theory it has a VERY high specific impulse, right? For a picosecond. Don't ion drives have excellent specific impulse? But they have barely any thrust and are not (at least not yet) practical means for propelling any serious spacecraft (in terms of mass).

And fission fragment rockets have a much higher ISP than Orion.

So what is the maximum speed reachable by a reasonably sized manned or unmanned spacecraft using fission fragment propulsion? You may say it doesn't matter, but then tell me how long it will take for a non-micro sized ship to get to Proxima Centauri using fission fragment propulsion. Has the math been done? Have you done it?

A rocket that propels itself by firing pingpong balls out the back with an air cannon can reach relativistic speeds

Prove it by building one.

As for the rest it is very interesting, but given the billions or trillions of dollars necessary could we build an interstellar ship with this system today using current tech that could reach Proxima Centauri in half a century? We know that we probably could do exactly that with Dyson's simple spring pusher plate pulsed system. Yes it is untested except at a ridiculously small scale, but it should all work using 1960s tech (and A LOT of money). As in any untested system it would probably fail dramatically the first few times, but at least no new tech is needed and plutonium in the form of bombs has the energy density to actually have enough fuel to reach high speeds. Lack of fuel is really the biggest problem with spacecraft propulsion. Not Isp. If we had infinite quantities of massless fuel we could reach relativisitic speeds easily even with standard chemical rockets. That's why every space enthusiast's dream is some kind of warp drive or space drive or ramjet or solar sail that doesn't require that you bring your fuel with you. What makes Orion or any nuclear pulse drive so special is that you can bring enough fuel with you for practical interstellar missions. I don't care about Isp. I care about the total trip time to various destinations like Proxima or Gliese 581.

Comment Re:Holy shitballs, all the sci-fi books were right (Score 1) 347

They'd just make kind of a mess in the atmosphere on their way up.

Which means you basically have to build them off planet. At a Lagrange point or on the moon or whatever. Yes it would probably add hundreds of years to the project to do that, but the alternative may be to never build an interstellar ship.

Comment Re:For values of 'nearby' that equal 'still very f (Score 1) 347

and we really don't have anything that can travel fast enough to get us there in less than tens of thousands of years.

Actually we really do. Stop spreading misinformation. We have had nuclear power since the 1940s. A lot of you people seemed to have forgotten this amazing 20th century invention and want to pretend that chemical rockets or ultra-weak ion propulsion are the only options based on current tech. They are not.

Comment Re:in 10+ generations (Score 1) 347

using as reference the speed of the fastest man-made space object

Was this 'object' actually designed for interstellar travel? If not then it is irrelevant. It's like saying the fastest bird only flies at 30 mph so what hope do we ever have of breaking the sound barrier. We have aircraft that can travel over 2000 mph because we designed them to do that. We have had the tech to reach around 0.08c since the 1960s. All we would need is the money to build the ship and admittedly it would be very, very, very expensive. Well unless it worked like an open source software project with people donating their time for free, but then of course it would take orders of magnitude longer.

Comment Re:Misquoted (Score 1) 347

Also: my understanding of the habitable zone of red dwarfs is that they leave their surfaces too irradiated for LAWKI.

It's more complicated than that. Red dwarves vary greatly in size from tiny like Proxima Centauri to something close to half the size of our sun and also vary a great deal in their luminosity variance. Proxima Centauri is highly variable and is what is known as a 'flare star' due to this. Then there is the issue of whether the planet is tidally locked in place or rotates. If it is tidally locked then there will always be a side facing away from the radiation. There are many factors involved.

Incidentally Mars and even Venus may have been genuinely habitable at one time. One theory of the origin of life on earth is that it originated on Mars first when the sun was younger and hotter. Obviously that is pure speculation but it's not impossible that Mars once had a thick enough atmosphere and a high enough temperature to support life.

Comment Re: interstellar mission (Score 1) 347

Give up? I'm not even working on space travel

Yes that is coming across.

_If_ humans ever do figure out how to travel between the stars, it will be in the very distant future.

Agreed. It would probably take 200 years just to build the infrastructure, manufacturing facility, and then the ship itself. Then another 50-100 years to make the trip. I'd consider 300 years to the be 'distant future' wouldn't you?

Comment Re: interstellar mission (Score 1) 347

Please explain the tech that we've had since to 50's to allow any complex machine (such as a nuclear reactor) to work unattended for 50 years.

So just to clarify, your argument as to why human beings cannot even travel as far as Proxima Centauri a mere 4 ly away is that our machines are not reliable enough? Seriously that is your argument? Voyager 1 has been operating for nearly 39 years without a problem. Yes it's RTG is winding down but it was never intended to be a true interstellar mission. A longer lasting power supply could have been built even back in 1977. And incidentally that was 1970s tech. Presumably we could build something even more reliable now with all the fancy new tech we have. We could even build an unmanned ship with a robot like this inside to at least try to maybe do some crude repairs. Yes a human onboard would be a huge advantage in terms of reliability, but there are also huge advantages to not having any delicate humans onboard.

Comment Re:interstellar mission (Score 1) 347

Sure. All we need to do is get past this trivial little hurdle of using chemical reaction motors to move things.

Bzzzt. Warp drive is not required to get to Proxima Centauri. The first (experimental) nuclear reactor was built in the early 1940s. Chemical reaction propulsion has not truly been required for something like 75 years. Nearly every machine we make could be powered by nuclear fission instead of heat engines. Note I say could be rather than should, but for spacecraft propulsion nuclear fission is still the best tech we've got.

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