PDA

View Full Version : Realistic Spaceships



cjackson
2014-Mar-05, 03:22 AM
Which science fiction spacecraft do you feel is most realistic? By realistic, I mean no warp drives, or any FTL, and that is theoretically plausible, if not technologically feasible.

Noclevername
2014-Mar-05, 03:26 AM
The Discovery from 2001.

SkepticJ
2014-Mar-05, 03:40 AM
The Venture Star from Avatar.

The Mars II from Mission to Mars. The movie is crapola, though.

Noclevername
2014-Mar-05, 03:47 AM
The Polaris from Tom Corbett, Space Cadet. The Rolling Stone from Heinlein's novel of same name. Both, IIRC, used "nuclear lightbulbs" (though that term didn't exist then) and hydrogen fuel.

The Michael, the Nuclear Pulse Orion from Niven and Pournelle's Footfall.

Noclevername
2014-Mar-05, 04:13 AM
Correction: the Polaris was a liquid-core NTR. I recall now that the reactor fuel was called "hot soup" and was drained into a tanker truck.

Doodler
2014-Mar-05, 04:34 AM
The Lewis and Clark from Event Horizon. Uses a form of ion drive and liquid acceleration tanks for high speed acceleration.

Noclevername
2014-Mar-05, 04:39 AM
The Lewis and Clark from Event Horizon. Uses a form of ion drive and liquid acceleration tanks for high speed acceleration.

If it (a large vessel IIRC) used an ion drive, how did it achieve high accelerations?

SkepticJ
2014-Mar-05, 05:06 AM
The Daban Urnud from Anathem - Orion-style nuclear pulse propulsion.

PetersCreek
2014-Mar-05, 05:12 AM
The Eagle Transporter from Space: 1999. Even though the supposed top end of 0.15c isn't plausible, I always thought the design was.

Noclevername
2014-Mar-05, 05:22 AM
The Starfuries from Babylon 5. Space fighters aren't all that realistic, but if you have to have them, at least then don't make them fly like a fighter plane!

Githyanki
2014-Mar-05, 06:00 AM
The deep-space craft from Deep-Space; it was a space-shuttle/apollo that could travel into the inner-system beyond the Moon!

Edit: and the Sulaco from Aliens; even if it couldn't go FTL, it still was an impressive military-spaceship.

Noclevername
2014-Mar-05, 09:09 AM
The Leonov from 2010, and its direct descendant, the warship Agamemnon from Babylon 5.

Agamemnon pointed a broad wall of weapons and a fighter launch bay towards its targets and made good use of point defense. The only unrealistic thing aside from jumpdrive, is that it didn't stop rotating its gravity section in combat; thus they were exposed to enemy fire twice every spin.

Noclevername
2014-Mar-05, 11:21 AM
How about the X-FLR6 Moon Rocket from Tintin?

litespeed
2014-Mar-05, 11:40 AM
How about the X-FLR6 Moon Rocket from Tintin?

V-2 derivative as was the Destination Moon ship !

Noclevername
2014-Mar-05, 11:57 AM
V-2 derivative as was the Destination Moon ship !

Only in appearance: instead of massive fuel tanks the interior was mostly an atomic drive and manned compartments.

Doodler
2014-Mar-05, 06:57 PM
If it (a large vessel IIRC) used an ion drive, how did it achieve high accelerations?

He did call it an "Enhanced Ion Drive", so I was assuming some level of generational improvement.

Krel
2014-Mar-06, 02:18 AM
The Starfuries from Babylon 5. Space fighters aren't all that realistic, but if you have to have them, at least then don't make them fly like a fighter plane!

The Starfuries were not realistic at all, and Foundation Imaging knew it. With the engines out on the ends of the 'wings' like that, the fighter would have been very hard to maneuver. The engines would need to be close in near the center of gravity, the closer the better. Foundation Imaging tried designing the fighter that way, but it never looked right visually. When you have a choice about what is scientifically accurate, and what looks scientifically accurate, the looks win.

I read once that in the 1950s, the U.S. built a fighter prototype that had the engines mounted on the wing tips. They found that the fighter would go in any direction the pilot wanted, as long as it was straight! :lol: It had zero maneuverability, and the wings had to be extra strong to take the weight of the engines at the wingtips.

David.

Noclevername
2014-Mar-06, 02:28 AM
The Starfuries were not realistic at all, and Foundation Imaging knew it. With the engines out on the ends of the 'wings' like that, the fighter would have been very hard to maneuver. The engines would need to be close in near the center of gravity, the closer the better. Foundation Imaging tried designing the fighter that way, but it never looked right visually. When you have a choice about what is scientifically accurate, and what looks scientifically accurate, the looks win.

The main engine is centrally mounted. The wingtip jets are for rapid maneuvering. This lets the SF spin in place on X, Y, and Z axes without altering its course, and shoot in any direction. It's all about angular momentum.

Krel
2014-Mar-07, 01:29 AM
The main engine is centrally mounted. The wingtip jets are for rapid maneuvering. This lets the SF spin in place on X, Y, and Z axes without altering its course, and shoot in any direction. It's all about angular momentum.

Look up images of the Starfury, the engines were mounted on the wing tips. At the conventions, when the show was on, Mojo from Foundation Imaging said that they knew when they designed them, that it was a bad design, too much mass on the wing tips. That would have made the Starfury very hard to maneuver, they had someone that worked out the math. But the designs that they did with the engines in close didn't look right, so they went with what looked good instead.

As the screenwriter William Goldman said, there is a difference between real, real and movie real.

David.

HenrikOlsen
2014-Mar-07, 12:26 PM
The mass on the wingtips is offset by it being the engines that are placed there so they act through a longer arm.
The argument against only works if there are aerodynamic forces on the wings which is patently absurd in space.

You might as well argues that a quad-copter can't balance because the rotors are too far from the center.

Noclevername
2014-Mar-07, 12:57 PM
He did call it an "Enhanced Ion Drive", so I was assuming some level of generational improvement.

Unless that's a euphemism for nuclear plasma, I can't see how the physics of ion drives would allow for any high-G thrust. It's kind of like saying your car can fly using an "enhanced ground wheel".

primummobile
2014-Mar-07, 01:02 PM
The shuttles in Armageddon

Noclevername
2014-Mar-07, 01:12 PM
The shuttles in Armageddon

The ones that flew around the back side of the Moon to catch up with the rock? On one main-engine refueling?

primummobile
2014-Mar-07, 01:21 PM
The ones that flew around the back side of the Moon to catch up with the rock? On one main-engine refueling?

And flew like airplanes in outer space and survived reentry after skidding to a stop on an asteroid? Yep.

Noclevername
2014-Mar-07, 03:14 PM
The George W. Bush from Iron Sky. At least, it was the closest thing to realistic in the film, aside from how fast it got to the Moon. (And of course the other nations' ships of the Earth fleet. Except Finland.)

Githyanki
2014-Mar-07, 10:18 PM
There's a little known supplement for Cyberpunk 2020 RPG game called, "Deep-Space", which had detailed and realistic rules for living, fighting and dying in space. They had cyclers, (space craft that orbited between objects in space, Deep-Space Explorers that were designed to go to say, Jupiter (and rules for radiation-belts and radiation in space), to Deltas (military attack craft) to shuttles and OTVs (Orbital-Transfer Vehicles) (shuttles/spaceplanes get you off of Earth, OTVs will get you to the Moon)(you can't hijack and shuttle and go to the Moon).

I agree with Babylon Five; their space-combat was and vehicles were realistic. Bab5 was in fact an O'Neil-station.

Trebuchet
2014-Mar-08, 04:07 PM
You might as well argues that a quad-copter can't balance because the rotors are too far from the center.

If one rotor stops, it can't. Same goes for engines far out on a wing -- as long as both are working, everything's fine. Rudders on airliner are sized entirely by controllability with one engine out on takeoff. The rest of the time, they're far larger than needed. For some reason, that won't work on a spacecraft.

publiusr
2014-Mar-08, 06:46 PM
The stretch LEM in MOON ZERO TWO,
The LV in JOE 90 and in "Journey To The Far Side Of The Sun"

http://catacombs.space1999.net/plus/dt/vcpgadp.html
https://coreldraw.com/media/p/74231.aspx

Doctor Longbore's UR-700 like vehicle at the end of LEXX (the Noah)

Doodler
2014-Mar-09, 02:22 PM
The mass on the wingtips is offset by it being the engines that are placed there so they act through a longer arm.
The argument against only works if there are aerodynamic forces on the wings which is patently absurd in space.

You might as well argues that a quad-copter can't balance because the rotors are too far from the center.

Add to this that the Starfury was never meant to operate in an atmosphere, and their positioning makes even more sense. She was a pure space fighter. Every other fighter on Bab5 was shown with the engines centrally located, except for the Minbari, and their tech entered the handwaving zone.

Noclevername
2014-Mar-09, 02:34 PM
It 's possible that there was a balancing system for the motors in case one was lost. It would make sense for a fighter craft to be able to operate on three engines. Throttle back the remaining engine output, or mount them on gimbals, to compensate for being off-balance.

Krel
2014-Mar-11, 03:05 AM
The mass on the wingtips is offset by it being the engines that are placed there so they act through a longer arm.
The argument against only works if there are aerodynamic forces on the wings which is patently absurd in space.

You might as well argues that a quad-copter can't balance because the rotors are too far from the center.

The fighter didn't have maneuvering problems because of aerodynamic forces, it had maneuvering problems because of the mass on the wing tips that had to be overcome. Look as a modern fighter jet, the engines are as close into the center of mass as they can get them. In an atmosphere, or in a vacuum, with that much mass extended out from the center of mass, that fighter is going to be as agile, and maneuverable as a drunken Manatee.

As Scotty said, you can not violate the laws of physics...Well, you can in movies and on tv, which is why a lot of things work in reel life that would not work in real life. :lol:

I don't see the similarity, besides quad-copters are designed for stability, not maneuverability, or agility.

David.

Solfe
2014-Mar-11, 03:14 AM
Count Dooku's Sail Ship was pretty neat, so long as you try not think about where he was going.

"Quickly! To the slowest escape ship in the Fleet!"

cjameshuff
2014-Mar-11, 04:13 AM
The fighter didn't have maneuvering problems because of aerodynamic forces, it had maneuvering problems because of the mass on the wing tips that had to be overcome. Look as a modern fighter jet, the engines are as close into the center of mass as they can get them. In an atmosphere, or in a vacuum, with that much mass extended out from the center of mass, that fighter is going to be as agile, and maneuverable as a drunken Manatee.

You're assuming they actually accounted for a substantial fraction of the fighter's mass. And even if they did, given the amount of thrust the engines had to have, the pilot would likely be the limitation in maneuvers.

Noclevername
2014-Mar-11, 07:52 AM
In an atmosphere, or in a vacuum, with that much mass extended out from the center of mass, that fighter is going to be as agile, and maneuverable as a drunken Manatee.



As I understand there is a central fusion core, which has valved plasma conduits leading out to the arms. So, again, the main engine is centralized.

NorthernDevo
2014-Mar-22, 05:55 AM
I'm probably going to get dragged over the coals for this; but I personally believe the Commonwealth Navy Corvette CNV-301 Dreadnaught (https://www.youtube.com/watch?v=C9AN1hpbw2Y)is perhaps one of the most accurately concieved spaceships in modern S-F. The physics are carefully accurate; and when accuracy fails very plausible S-F pseudoscience is substituted for an extraordinarily satisfactory playing experience. :) Independence War (or I-War; in Europe) is one of the very best space combat sims ever made; its fans remain legion to this day; myself amongst them.

Moose
2014-Mar-22, 04:20 PM
The fighter didn't have maneuvering problems because of aerodynamic forces, it had maneuvering problems because of the mass on the wing tips that had to be overcome.

... by the corresponding amount of torque you've clearly forgotten about. Agility is a matter of offset thrust on one side and offset counter-thrust on the opposite side. What you call 'main engines', I call oversized (http://www.planet3earth.co.uk/starfury3.jpg) RCS thruster arrays.

Moose
2014-Mar-22, 04:28 PM
Count Dooku's Sail Ship was pretty neat, so long as you try not think about where he was going.

"Quickly! To the slowest escape ship in the Fleet!"

Gorgeous looking, and only problematic if you assume the sail was propulsion. I say he really _really_ wanted his in-flight HBO (Hutt Broadcasting...)

/ Monday night Huttball broadcast of a playoff season elimination game (where the players are literally eliminated.) Who'd want to miss that because of the outbreak of a pesky border war?

Krel
2014-Mar-23, 02:54 AM
... by the corresponding amount of torque you've clearly forgotten about..

Nope. Didn't forget about it, because I don't know about it (and thank you for the snide insult). What I am going on is what I have read. In the case of the fighter, it is several decades old, I don't even remember if the book had an actual photo of the jet or just a drawing. I just remember that the book talked about the problem of having engines on the end of the wings. It didn't work.

In the case of the B5 Starfury, I am going on what the designer said at a convention. He said that they knew it was a design that would not work, and why, but they used it because it looked so good. The same with the Starfury cockpit. They knew that the pilot should be in a vertical acceleration couch, but it was cheaper and easier just to have them stand against a flat board. It was a low budget show.

David.

Solfe
2014-Mar-23, 03:56 AM
Gorgeous looking, and only problematic if you assume the sail was propulsion. I say he really _really_ wanted his in-flight HBO (Hutt Broadcasting...)

/ Monday night Huttball broadcast of a playoff season elimination game (where the players are literally eliminated.) Who'd want to miss that because of the outbreak of a pesky border war?

In DS9, the Bajorans (http://en.memory-alpha.org/wiki/Bajoran_lightship)used lightsail ships. They weren't warships, but they were for fun and exploration. The sails are way too small, but they are pretty looking.

Van Rijn
2014-Mar-23, 09:17 AM
In DS9, the Bajorans (http://en.memory-alpha.org/wiki/Bajoran_lightship)used lightsail ships. They weren't warships, but they were for fun and exploration. The sails are way too small, but they are pretty looking.

That one annoyed me. The design didn't make sense, it would take ages to go anywhere, and then they threw in tachyons as well (they were also tachyon sails).

Moose
2014-Mar-23, 11:46 AM
Nope. Didn't forget about it, because I don't know about it (and thank you for the snide insult).

Wasn't meant unkindly. You'd neglected the torque. I'd figured you'd simply forgotten about it.

Torque is pretty simple. It describes what's going on when you press down on a lever. Numerically, it's the applied force multiplied by the distance from the pivot. If you press down on a seesaw at the end, you're delivering twice as much torque using the same amount of force as if you pressed down half-way up the seesaw. That same (but opposite) torque exists on the other side of the pivot which you can use to act upon some load.

So yeah, in an airless environment, there's some multiple of engine mass to move out at the end of the wings, which matters, but the engines also provide that same multiple of torque to turn the spacecraft. That said, if the engines weren't independently throttleable, then yes, you'd have agility problems while all four were operating at the same thrust. But only while all four were operating at the same thrust.

As was mentioned before, the problem with engines at the end of a wing in an atmosphere is almost entirely caused by aerodynamic forces. It's not a big deal for space travel. As I said, think of it as an oversized RCS array, because that's really what it is.

Solfe
2014-Mar-23, 02:51 PM
I forgot about the light sail vs. tachyons on DS9. How could I forget about how tachyons work on Star Trek??? :)

Noclevername
2014-Mar-23, 04:29 PM
That one annoyed me. The design didn't make sense, it would take ages to go anywhere, and then they threw in tachyons as well (they were also tachyon sails).

That one, even the writers admitted, was designed purely for the "cool factor". It was never meant to be practical.

For example, if the ancient Bajorans could reach orbit at all, they surely would have had something better than manual cranks to move the sails!

(Just one problem among many. Like, the writers also forgot that in the pilot ep. They had moved the station to the outer edge of the star system... there'd be no light to sail!)

HenrikOlsen
2014-Mar-29, 07:46 PM
Nope. Didn't forget about it, because I don't know about it (and thank you for the snide insult).
If you don't understand how putting the engine farther from the center of gravity increases the turning torque it provides, and that this increase is larger than the increased turning momentum, how can you even try to argue the merits of any design?

cjameshuff
2014-Mar-29, 08:16 PM
If you don't understand how putting the engine farther from the center of gravity increases the turning torque it provides, and that this increase is larger than the increased turning momentum, how can you even try to argue the merits of any design?

The moment of inertia of the engine pods increases with r^2, while the torque increases with r. However, the moment of inertia of the fighter is not entirely due to the engine pods, and considering they are reaction drives, it's reasonable to expect them to be largely hollow. There will be some optimal separation, above which the increased moment of inertia exceeds the increased torque, but below which the lost torque exceeds the reduced moment of inertia.

And considering that those tip mounted thrusters are capable of accelerating the entire fighter at multiple gravities, even in the worst case where all the mass was in the engine pods, you'd probably need to limit the thrust in turns to prevent injury and keep the fighter controllable.

Krel
2014-Mar-30, 12:06 AM
If you don't understand how putting the engine farther from the center of gravity increases the turning torque it provides, and that this increase is larger than the increased turning momentum, how can you even try to argue the merits of any design?

Because, as I have explained above, I am going on what I have read in the past, and what I was told by the Starfury designer. When the designer tells me that his design is not accurate, and would not work in real life, but was done purely for looks, I take him at his word.

David.

Moose
2014-Mar-30, 12:35 AM
Because, as I have explained above, I am going on what I have read in the past, and what I was told by the Starfury designer. When the designer tells me that his design is not accurate, and would not work in real life, but was done purely for looks, I take him at his word.

Are you sure he wasn't talking about Thunderbolt Starfuries in atmosphere? Because your reporting of his objections would fit a little better if he had been.

HenrikOlsen
2014-Mar-30, 03:46 PM
The moment of inertia of the engine pods increases with r^2, while the torque increases with r.
You're right, I should have mentioned that the increase in momentum is offset by the torque because it isn't all the mass that's in the engines.
Your statement that there's an optimal separation is clearer than my comment.

I was thinking of the tangential acceleration caused by the thrusters rather than the angular.
If all the mass is concentrated entirely in the thrusters, then it's the tangential acceleration which is constant regardless of separation, which means the angular acceleration drops with thruster separation.
But with some of the mass concentrated in the center, there's a constant term in the moment of inertia from the rest of the mass which will be larger that the term from the thrusters until the separations gets to the optimum point.

Krel
2014-Mar-30, 10:00 PM
Are you sure he wasn't talking about Thunderbolt Starfuries in atmosphere? Because your reporting of his objections would fit a little better if he had been.

No, this was before the Thunderbolts were introduced, although he did talk about the new fighters, the Thunderbolt, that were suppose to take the place of the Starfury. For some reason they decided to keep the Starfury, and never used the Thunderbolt much.

David.

NorthernDevo
2014-Mar-31, 04:16 AM
No, this was before the Thunderbolts were introduced, although he did talk about the new fighters, the Thunderbolt, that were suppose to take the place of the Starfury. For some reason they decided to keep the Starfury, and never used the Thunderbolt much.

David.

Sorry; just enjoying this argument :) Obviously; the reason the Fury survived and the Thunderbolt didn't had to do with the SFX department's need to keep the budjet down, or something prosaic like that; but if we can for interests sake project the thought into the B5 Universe; is it possible the Thunderbolt was an ambitious, but ultimately failed upgrade of the Star Fury design? Star Furies perform in space; and do so superbly throughout the course of the show. Thunderbolts appear less often. They are obviously much larger and heavier than Furies; my question is did the addition of atmospheric flight - a heavier body; all the extra equipment and machinery - simply make the Thunderbolt too heavy to be serious threat in space combat? IOW was the Thunderbolt the Y-Wing to the Furie's X-Wing?

Its an interesting, and very cool, thought :D

Elukka
2014-Mar-31, 09:02 AM
Space F-35. :p

Moose
2014-Mar-31, 11:59 AM
Sorry; just enjoying this argument :) Obviously; the reason the Fury survived and the Thunderbolt didn't had to do with the SFX department's need to keep the budjet down, or something prosaic like that; but if we can for interests sake project the thought into the B5 Universe; is it possible the Thunderbolt was an ambitious, but ultimately failed upgrade of the Star Fury design? Star Furies perform in space; and do so superbly throughout the course of the show. Thunderbolts appear less often. They are obviously much larger and heavier than Furies; my question is did the addition of atmospheric flight - a heavier body; all the extra equipment and machinery - simply make the Thunderbolt too heavy to be serious threat in space combat? IOW was the Thunderbolt the Y-Wing to the Furie's X-Wing?

Heh. First off, the Y-Wing came first.

But yeah, select squadrons were being upgraded with Thunderbolts around the turn of season 3, IIRC. There was a mention that Babylon 5 was scheduled to receive a squadron (IIRC, Zeta wing was slated for the upgrade, which caused some chafing between them and the other two squadrons) but I can't remember if they actually received them or not. I'd argue that there probably wasn't much point in Bab5 getting any, since they had no need for atmosphere-capability, but (IIRC) during that season, Sheridan was still believed to be one of Clarke's rising stars, so I suspect the squadron upgrade was intended to be a plum more than a genuine extension of needed capability.

After things got chilly, though, it would have been story-breaking for Babylon 5 to receive any significant material support from Earth right up to the very end of the series, even the Lochley year.

NorthernDevo
2014-Apr-01, 04:39 AM
Heh. First off, the Y-Wing came first.
Yes, I know. I was referring to the relative effectiveness of an older strike craft against a modern space-superiority fighter.


But yeah, select squadrons were being upgraded with Thunderbolts around the turn of season 3, IIRC. There was a mention that Babylon 5 was scheduled to receive a squadron (IIRC, Zeta wing was slated for the upgrade, which caused some chafing between them and the other two squadrons) but I can't remember if they actually received them or not. I'd argue that there probably wasn't much point in Bab5 getting any, since they had no need for atmosphere-capability, but (IIRC) during that season, Sheridan was still believed to be one of Clarke's rising stars, so I suspect the squadron upgrade was intended to be a plum more than a genuine extension of needed capability.
An excellent summation; and perfectly understandable given the political situation. T-Bolts might not have been useful to B5 but they were new and shiny; and thus a politically valid benefit. Whether their tactical benefit is positive is another matter, of course. :D


After things got chilly, though, it would have been story-breaking for Babylon 5 to receive any significant material support from Earth right up to the very end of the series, even the Lochley year.

NOOOOO! Not Lochley! AAAAAHHHH!

Ahem.
:rofl:

Krel
2014-Apr-02, 12:49 AM
Sorry; just enjoying this argument :) Obviously; the reason the Fury survived and the Thunderbolt didn't had to do with the SFX department's need to keep the budjet down, or something prosaic like that;

The problem with that argument is that they had already created the Thunderbolt cgi files, and built the cockpit set. By not using the Thunderbolt, they were losing money spent on the new, more elaborate set and cgi files. Perhaps the Thunderbolt didn't didn't test well.

I too am enjoying the discussion.

David.

Solfe
2014-Apr-02, 01:43 AM
Someone went and plugged in the Blackbird cgi files into the rendering of a space battle. This was the cgi team messing around - the ship wasn't completed yet and didn't fly very well once it was completed.

I liked the Blackbird (http://en.wikipedia.org/wiki/Colonial_Blackbird), they should have built more.