Lorbo's Mega Tech Thread (so I won't spam)

[lorbo]

I have a lot of thoughts about how science fiction differs from reality. So I will post them here rather than make mulitple posts and spam the forum.

1. The movie Gravity was awesome. For any physics lover.

2. About Waste Heat In Space: I did some research on why spaceships need radiator fins. Well it turns out on Earth we can cool things just by manipulating electric current (the basis of refrigerators). Now you'd think we could carry that into space as a heat sink (we do, but mainly for power), yet there is a huge problem.

As far as we know, it's downright impossible to convert 100% heat into 100% electricity. If through some superhman effort you get 99% of the heat converted into electricity (tell me if any human has managed that, I doubt it), you still have that 1% of waste heat on your spaceship. And that will stay there unless you radiate it away from your spaceship, or cool your spaceship down by coolant.

That 1% of space heat could be very hot, depending on how much heat your converting, and if you have really powerful engines (you need them in space to get anywhere fast), then you do for sure. So radiators or coolant are the only realistic way to go.

That said, radiators and coolant are curiously absent in popular science fiction on TV.

So that means something. The writers ignored it, but I will think of some way their spaceships could manage waste heat, since they never bothered to explain.

Star Trek/Star Wars ships somehow covert 100% of the heat from their engines into electricity. I suppose that may be reasonable, if you consider that their tech is supposed to be more advanced.

Whether or not it's possible is up in the air. It's safe to say that if we ever manage that, Earth's energy problems will be a thing of the past likely.

[Dywyddyr]

Well it turns out on Earth we can cool things just by manipulating electric current (the basis of refrigerators).

No. It's nothing at all to do with "manipulating electricity".

Star Trek/Star Wars ships somehow covert 100% of the heat from their engines into electricity.

Citation needed.

I suppose that may be reasonable

It's not reasonable.

[lorbo]

Which Sub-light would you choose?

1. Ignore the impossiblity of it, alright. Gravity drive: Allows your spaceship airplane like maneuverability in space. Drawback: No artificial gravity inside your spaceship, because your using it to propel your ship. The ship moves by gravity pulling it in the direction it wants to go, sometimes along different vectors to simulate airplane maneuvers.

2. Compressed Plasma Drive: You ship expels hot plasma like a rocket, which propels your ship. Your ship moves according to real physics, so no airplane maneuvers are possible. However you do get gravity generation inside your ship, so you won't have to worry about weightlessness.

You have a lot of plasma aboard, since you use gravity to compress it, like a mini star. When you run out you will have to refuel at the nearest star. Your ship can take star heat for an hour, so that won't be a problem. It will take you 30 minutes to fill up completely. You use gravity tractor beams to suck up plasma into your ship for use in you engines. Once full, you engines only require refueling every four months, and that's only if you use them constantly.

So which ship would you want?

For long term exploration I would pick the gravity drive ship, and just tough out the weightlessness. Exploration crews would of necessity be small, as would the ships. But for missions where I would transporting tons of people, I would use plasma drive ships. So they would be comfortable.

And I didn't mention it, but gravity drive ships can't use gravity tractor beams, since their outer gravity field interferes with it. So plasma drive ships lack the maneuveriblitiy and require refueling, but give you more options and comfort. Gravity drive ships offer virtually limitless fuel so long you have power, and their maneuverability is great from a combat perspective.

[lorbo]

[QUOTE=Dywyddyr;494502]

Well it turns out on Earth we can cool things just by manipulating electric current (the basis of refrigerators).

No. It's nothing at all to do with "manipulating electricity".

Read and learn: Thermoelectric cooling - Wikipedia, the free encyclopedia

[Dywyddyr]

Gravity drive: Allows your spaceship airplane like maneuverability in space

No it doesn't.

Drawback: No artificial gravity insider your spaceship, because your using it to propel your ship

What?

You have a lot of plasma aboard, since you use gravity to compress it

What?

For long term exploration I would pick the gravity drive ship, and just tough out the weightlessness

So you're ignoring the long-term effects of "zero g" on humans?

[Dywyddyr]

[QUOTE=lorbo;494504]

Well it turns out on Earth we can cool things just by manipulating electric current (the basis of refrigerators).

No. It's nothing at all to do with "manipulating electricity".

Read and learn: Thermoelectric cooling - Wikipedia, the free encyclopedia

Can you quote the part that says that effect is used in refrigerators?
"A camping/car type electric cooler can typically reduce the temperature by up to 20°C (36°F) below the ambient temperature" - hardly refrigeration temperatures.

And for spacecraft use: The effect is used in satellites and spacecraft to counter the effect of direct sunlight on one side of a craft by dissipating the heat over the cold shaded side, whereupon the heat is dissipated by thermal radiation into space.
I.e you STILL need thermal dump panels.

[lorbo]

For long term exploration I would pick the gravity drive ship, and just tough out the weightlessness

So you're ignoring the long-term effects of "zero g" on humans?[/QUOTE]

Why yes. We can survive for years in zero G. You will be weak when you leave the craft I know, but I have forms of FTL, which I won't mention. The drives i have mentioned are merely for sublight, and for dedicated explorers. It's expected that if you have gravity manipulation under your belt as a skill, then you should be able to heal the human body back to normal withoul too much trouble when you leave a zero G enviroment. Preparation is everything.

[Janus]

2. About Waste Heat In Space: I did some research on why spaceships need radiator fins. Well it turns out on Earth we can cool things just by manipulating electric current (the basis of refrigerators). Now you'd think we could carry that into space as a heat sink (we do, but mainly for power), yet there is a huge problem.

Refrigerators work by compressing gas until it turns into a liquid, which is then pumped though the coils on the back of the refrigerator so it can bleed off the excess heat. The now cooled liquid flows back into the refrigerator where it is allowed to expand back into a gas. This cools the gas considerably, and it absorbs heat from the surroundings. It then returns to the compressor and back to the coils where it bleeds off the heat it gains. This works because after the compressor, the liquid is much warmer than the outside air, and the expanded gas is colder than the interior of the refrigerator. It is basically pumping heat from inside the refrigerator to outside of it. This is helped by the fact that the outside coils, in heating the air cause an updraft which brings new cool air in contact with the coils. Thus the coils lose heat by radiation, conduction and convection.

The issue with a spacecraft is that it can only lose heat by radiation, as the vacuum of space does not support conduction or convection. Thus the ship can only lose heat through any radiating surfaces it has.

While not mentioned directly in the show, Star Trek does make a nod to this need. If you look at the nacelles, On the inward sides there are panels that look like radiators. Probably not large enough to properly do the job, but they didn't ignore the need altogether. Again, the likely reason for this never being mentioned in the show is that no one ever wrote a story where it was needed for the plot.

[Dywyddyr]

Why yes. We can survive for years in zero G.

Right.

[lorbo]

[QUOTE=Janus;494514]

Refrigerators work by compressing gas until it turns into a liquid, which is then pumped though the coils on the back of the refrigerator so it can bleed off the excess heat. The now cooled liquid flows back into the refrigerator where it is allowed to expand back into a gas. This cools the gas considerably, and it absorbs heat from the surroundings. It then returns to the compressor and back to the coils where it bleeds off the heat it gains. This works because after the compressor, the liquid is much warmer than the outside air, and the expanded gas is colder than the interior of the refrigerator. It is basically pumping heat from inside the refrigerator to outside of it. This is helped by the fact that the outside coils, in heating the air cause an updraft which brings new cool air in contact with the coils. Thus the coils lose heat by radiation, conduction and convection.

The issue with a spacecraft is that it can only lose heat by radiation, as the vacuum of space does not support conduction or convection. Thus the ship can only lose heat through any radiating surfaces it has.

While not mentioned directly in the show, Star Trek does make a nod to this need. If you look at the nacelles, On the inward sides there are panels that look like radiators. Probably not large enough to properly do the job, but they didn't ignore the need altogether. Again, the likely reason for this never being mentioned in the show is that no one ever wrote a story where it was needed for the plot.

I certainly never considered that the Trek nacelles might be radiators. But if they are, they aren't situtated right. You don't wan't radiators radiating heat inwardly towards your ship. Not if you want to dump heat, which is the whole purpose of radiators.

I think the TIE fighters in Star Wars have at least one thing right. Those panels, which they call solar collectors, would be better suited as radiators. But they probably aren't big enough, unless those weapons of theirs are cheap. Meaning they offer big bang for low heat dispersion (scifi has done worse admittedly). The X-wings on the other hand, are a pure abomination.

[Dywyddyr]

But they probably aren't big enough, unless those weapons of theirs are cheap. Meaning they offer big bang for low heat dispersion (scifi has done worse admittedly).

Generally the cheaper something is the less efficient it is: ergo a cheap weapon will generate more heat.

[lorbo]

But they probably aren't big enough, unless those weapons of theirs are cheap. Meaning they offer big bang for low heat dispersion (scifi has done worse admittedly).

Generally the cheaper something is the less efficient it is: ergo a cheap weapon will generate more heat.

You could be right then. I guess those TIE fighters would be really expensive. No wonder why the Empire was defeated. The X-wings were going through those TIE fighters like wasps in a beehive (30 wasps vs 2000 bees and the bees lose horribly).


Hey, i think we just figured out the basis of Star Trek/Star Wars tech. They don't need stinking radiators. Their ships have lots of bang for the buck, being ridiculously low on heat dispersion.

They don't generate enough heat to be fatal. So they don't require radiators.

Ooops, even this is flawed, because if that was the case the temperature inside wouldn't be all that comfortable would it? Or maybe it could? The Apollo 13 mission had no radiators and were fine till they lost power. At that point they almost froze to death.

So basically, a ship that didn't generate deadly heat due to low heat high perfomance engines/power supply would have an internal temp similar to Apollo 13 spacecraft when it was working properly.

[Flick Montana]

The X-wings were going through those TIE fighters like wasps in a beehive (30 wasps vs 2000 bees and the bees lose horribly).

Ironically, bees often kill intruder wasps using heat generation as their weapon.

In regards to your love of the film Gravity, it always bothered me how much more interested we are in Hollywood depictions of adventures in space than we are actual adventures in space. Gravity was a film with some serious scientific flaws. 7 Minutes of Hell is a much better film with significantly more impressive science.

[lorbo]

Switch the subject:

Astronauts dump their clothes since having a washing machine in zero g is counter intuitive (water don't go anywhere and is a lot like glue).

So I challenge you to sci-fi a way out of it. What are someways you could have reusable clothing? In a zero G evironment. Instead of having to dump them all the time? For deep space travel, dumping clothes would be an issue (even with high speeds because space is HUGE).

Solution: Metal clothing: Armor plating for clothes. Yeah, I'm talking metal underwear too. Joints on it for flexibility. Wanna clean it when it gets full of your sweat and skin flakes? Send it to a hot room that heats it up and kills all that junk.

Wait till it cools and you got your clothes back. Ideally, you would have heat and cooling systems that would work fast enough so that you wouldn't be naked for longer than 5 minutes while you waited for your clothes.

[Flick Montana]

Funny that you made this thread so as not to spam, yet you created a whole new thread about the post above...