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Spaceships and Science fiction

by SHISHKABOB
Tags: fiction, science, spaceships
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Ryan_m_b
#91
Jan15-13, 05:54 AM
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Quote Quote by GTOM View Post
(And it only has to patrol between areas of interest and act if necessary, otherwise its simple presence is threatening to bad guys. At first level i think about an operational area of Earth's orbit or Earth to Moon.)
Space is big. Patrolling between areas of interest is at best going to take days (Earth-Moon system) and at worse years. There is no point sending a craft on a continual loop between interesting locations on the off chance that during its months/year long round trip something might happen at just the right moment for it to be around to help. This is why the idea of patrolling makes no sense.

Similarly if it takes years to get anywhere then by the time you get there the thing to came for is likely to be over. If military presence was deemed to be a necessity then it's likely to be a permanent, on site feature rather than something that is moved around like today.
Quote Quote by cephron View Post
Fascinating! I'll have to read up on this. Would you basically need multiple neutrino detectors arranged at distance from each other, in order to pick up relative differences and calculate the position of the source? Or can a single detector obtain the direction of the source?

*goes off to wikipedia...*
I'm not sure, I'm guessing several.
Quote Quote by ImaLooser View Post
The thing about space combat is that it is very difficult to hide anything. Even with today's technology tiny things can be tracked.
Quite, it's even easier when the object in question is several hundred degrees hotter than its surroundings http://www.projectrho.com/public_htm...ealth_In_Space
Quote Quote by ImaLooser View Post
My guess is that any kind of space combat would be so fast and secretive that it would all be done by computers. There would be no human involvement at all. You would be flying along and either suddenly cease to exist or get a computer message that you just won.

Any ordinary space ship would have a tiny crew that was bored as could be, just waiting for something to repair. Any sort of warship would be completely unmanned.
It really depends on what we mean by space combat. Curiously we don't generalise for anything else, why space?
GTOM
#92
Jan15-13, 06:22 AM
P: 116
What about orbital patrol? The ranges are smaller.

I think about the descandants of this : http://en.wikipedia.org/wiki/Boeing_X-37

(Ok, than no frigates just destroyers with Earth to Moon range...)

I would be still curious : if we can already see distant planets, why USA sends drones to unfriendly countries, where they are shot down and hacked up? Why cant they solve recon with a big orbital scope? I dont think a RQ-170 Sentinel could enter into buildings, overhear conversations...
Is it because the distortion of the atmosphere, or what?


Otherwise I can agree that short range craft can be remote controlled, but i sure wouldnt trust decision making to compus (at least... ). It would be too much temptation to politicans and military leaders.
A drone operator can still feel remorse, guilt.
Ryan_m_b
#93
Jan15-13, 06:56 AM
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Quote Quote by GTOM View Post
What about orbital patrol? The ranges are smaller.
You can drop patrol there and just say orbit unless you want a craft tat burns through all its few a short time after deployment. Otherwise sure.
Quote Quote by GTOM View Post
I think about the descandants of this : http://en.wikipedia.org/wiki/Boeing_X-37
I doubt like this. I'm thinking more along the lines of the international space station with more propulsion and weapons. Not a space plane. You can't dog fight in space and there isn't a role that I can see for a fighter type craft between larger craft and smaller missiles.
Quote Quote by GTOM View Post
I would be still curious : if we can already see distant planets, why USA sends drones to unfriendly countries
Firstly our detection of exoplanets is not by seeing them directly, but by observing the effect they have on their sun. Secondly whilst we can see planets in this system there are things that telescopes can't do that we use probes for. Thirdly what we're talking about in this thread is the detection of spacecraft which would not be done by visual means of the craft itself but by thermal means of it and its exhaust. Lastly satellites in Earth orbit have only a tiny amount of the the surface they can see at any one time in their orbit (presuming no cloud cover and its day). No nation has so many satellites that they can see any point on Earth at any time so drones are used (amongst other reasons).
GTOM
#94
Jan15-13, 09:05 AM
P: 116
"I doubt like this. I'm thinking more along the lines of the international space station with more propulsion and weapons. Not a space plane. You can't dog fight in space and there isn't a role that I can see for a fighter type craft between larger craft and smaller missiles."

I think that depends on exactly what you want to achieve. (And what kind of engine developments can we achieve.)

Ok if you can barely have enough delta-V to reach a certain target and only want to destroy that, yes you use a missile.

If you want to reach multiple targets, you can provide enough delta-V, and maybe not destroy just capture some of them, i see a role for smaller planes.

For example you might want protect your own satellites meant to watch a country, attack the satellites (and anti satellite missile sites) of that country, that means all of them will fly above that country.
Then you can position a squadron of small ones to a low orbit, where they might protect an own satellite at first, bomb a missile site next, then modify orbit to attack an enemy satellite. (They might use the upper stratosphere to modify their vector?)
During this, you might want to keep your precious station on a high orbit, possibly GEO above your country. (if they have the technology to attack it... yes it can defend itself much better than the small ones, but you can afford to lose some of the small ones, while you dont want to endanger a big station)

Or you want to capture a rocket of a crime lord, before it could reach a safe haven.
A missile cant capture a ship, a plane can fire warning shots to it, and only destroy it if absolutely necessary. Ok you might fire a missile and blow it up, if they modify their course, but you sacrifice the missile.
Assuming that fuel will be cheap enough, and there will be cheap methods to get it to orbit (asteroid mine, induction catapult, space elevator from Moon) it is better to sacrifice fuel then missiles, and care about versatility and reusability.
(Well intercontinental ballistic missiles exists for long, there are also high-precision missiles, but attack vehicles are still needed. )

I have a Mohs scale 5 situation in mind.
Ryan_m_b
#95
Jan15-13, 09:17 AM
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You're really underestimating how much all that manoeuvring is going to cost in terms of fuel and energy and therefore mass and therefore thrust. Orbital speed it a hell of a lot faster than anything in atmosphere. You can't just shed that and speed off in other directions. On top of that you should brush up on the basics of orbital mechanics, you can't have a squadron of planes hovering under the orbit of a satellite, at least not without constant thrust. On top of that none of the tasks you mention would be best suited to planes over weaponised satellites.

Regarding capturing a craft that's pretty much impossible. It requires you carefully match velocity and gently dock. Not going to be possible if the other craft doesn't want you too, all they have to do is spin their craft along its axis and you're screwed.

I'm sorry but this isn't moh-5, more like 2. I think you're basing too much of this on science fiction and not science.

This thread has gone on long enough with no development. I suggest we take a break until anyone has something definitive to discuss I.e some actual science to speculate on or some fiction to talk about.
GTOM
#96
Jan15-13, 03:08 PM
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Ok, weaponised reloadable satellites.
I hope this is a development, if not, than sorry, do what you have to do.


Another things : in space there are pretty much radiation. Earth is protected by its magnetic field from the worst things. Could this be a viable method to protect spaceships (colonies) instead of thicker hulls?
Ryan_m_b
#97
Jan15-13, 03:15 PM
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There is research along those lines
http://physicsworld.com/cws/article/...ect-spacecraft
GTOM
#98
Jan16-13, 02:20 AM
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Thank you.


A bit more about protection and sci-fi : i found a link in this forum, in an experiment they used magnetic fields and lasers to keep particles at one place. When they released them, they drew away that much energy, that they called their state beyond absolute zero...
Is there any chance that this super entropy-less state could be used to create some supersolid armor? (well a bit like to the concept of energy shield)

Second, about induction catapults, mass drivers, coilguns.
What could be the theoretical limit of acceleration, that a simple solid object could withstand without ripped to plasma dust?

So for example, if one would like to take out a meteor, and boost a projectile to 10km/s in order to do it, what could be the minimum length of the coilgun?
(Assuming, with some next generation technology, they can solve power supply, engineering, recoil etc)
Ryan_m_b
#99
Jan16-13, 05:35 AM
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Here is the PF discussion on the topic http://physicsforums.com/showthread.php?t=662268.

Re acceleration if it is uniform across the object then the answer is infinite. If not it's down to the material properties of whatever it is made out of. Re length it depends on how fast you're accelerating. Ask in one of the physics forums if you want to learn how to work it out.
GTOM
#100
Jan17-13, 01:05 PM
P: 116
Ok, thank you.

(And again, sorry for our previous misunderstainding. :( I should have made it clear that I imagined the orbital craft to operate in a wider orbital belt, so it could observe and attack more, gradually modificating course during turn around the planet, and by capture, i meant, force to surrender by lethal threat. )
Ryan_m_b
#101
Jan18-13, 12:11 PM
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Quote Quote by GTOM View Post
Ok, thank you.

(And again, sorry for our previous misunderstainding. :( I should have made it clear that I imagined the orbital craft to operate in a wider orbital belt, so it could observe and attack more, gradually modificating course during turn around the planet, and by capture, i meant, force to surrender by lethal threat. )
No worries. But do go and look into how orbit works. It's vastly different to any medium on Earth with the speeds, distances and vacuum making zipping around like any terrestrial transport impossible.
GTOM
#102
Feb2-13, 05:33 AM
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I read about orbital mechanics, i think its a must have to SF writers (who want to deal with space).
Yes an inclination change isnt something that can be taken lightly...
Although i saw methods that could make that easier.

1 : scratch the stratosphere, then ascend
2 : take an elliptical path, and change inclination at apophis, where speed is smallest
3 : use recoilles stuff, like magnetic fields in the magnetosphere

I wonder whether magsails could take over rockets, if big acceleration isnt needed?
(Since there arent confirmed progress with anti gravity, space time warp, sails are the only recoilles methods. )
Vierstein
#103
Feb6-13, 06:49 PM
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Quote Quote by SHISHKABOB View Post
Moderation note: This thread has been split from another so as not to derail the former thread

I have a hard time enjoying Star Wars anymore because of how those spaceships fly around :(
What you dont like the sound they make in space?

VRROOOOMMM XD
Traz 0
#104
Feb19-13, 04:10 PM
P: 11
I'm not sure which of the split threads this belongs in, but ...

Footfall, by Larry Niven and Jerry Pournell had what seemed to me at the time (1985) to be some very well thought out space combat. Human versus alien, where the aliens have superior tech but we have desperation. We launch a supermassive Orion-type carrier ship (from earth ... Desperate!) accompanied by a fleet of shuttles. The primary weapons used are x-ray lasers pumped by the orion drive. The aliens are dumbfounded by the reckless tactics.

Niven and Pournell are famous for hard SF, and if I recall correctly, Pournell worked on a real life space-based kinetic weapon system which was never deployed (or was it? ;-) ) called Thor or Thads ...
Traz 0
#105
Feb19-13, 04:21 PM
P: 11
I just realized that I didn't define the Orion drive. Project Orion was a real life proposal to propel a spacecraft by exploding nuclear bombs behind a pusher plate. I suspect that it would be a bumpy ride ...
ImaLooser
#106
Feb19-13, 08:49 PM
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Quote Quote by Traz 0 View Post
I just realized that I didn't define the Orion drive. Project Orion was a real life proposal to propel a spacecraft by exploding nuclear bombs behind a pusher plate. I suspect that it would be a bumpy ride ...
I remember that. One of the scientists involved in launching a small chemical prototype said, "This is not nuts, this is supernuts."
Traz 0
#107
Feb20-13, 02:12 PM
P: 11
Quote Quote by ImaLooser View Post
I remember that. One of the scientists involved in launching a small chemical prototype said, "This is not nuts, this is supernuts."
Well, I certainly wouldn't want to live downwind of a surface launch.

As far as a Project Orion space drive, I suppose that its feasibility is partially an engineering problem, and partially political, i. e., who would I trust in possession of hundreds of nukes in space, how they could be secured, etc. Barring an alien invasion or a dino-killer space rock with our name on it, my vote would be, uh, no thanks.
Traz 0
#108
Feb22-13, 05:19 PM
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Quote Quote by Ryan_m_b View Post
No worries. But do go and look into how orbit works. It's vastly different to any medium on Earth with the speeds, distances and vacuum making zipping around like any terrestrial transport impossible.
From the Robert Heinlein wiki:

Heinlein himself stated - with obvious pride - that in the days before pocket calculators, he and his wife once worked for several days on a mathmatical equation describing an Earth-Mars rocket orbit, which was then subsumed into a single sentence of the novel Space Cadet.


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