Spaceships that "fly" annoy me

[Ben90]

I'm surprised no one has posted this yet.

Hell, there is more than one of them.

 

[Eureka]

Because actual space 'flight' mechanics would be boring. Even with thrust vectoring you wouldn't really turn, you'd just rotate around your center of mass until you're pointing the right way. You never cancelled out that original vector of travel. So you'd just be tumbling around in space. And nobody wants to watch a bunch of spinning pieces of metal for 2 hours.

 

[chihlidog]

Another vote for Kerbin Space Program. I only recently discovered it, and while the Kerbals themselves are silly (and hilarious when launched), the game is utterly fascinating, addicting, maddening, frustrating, and overall fantastic.

 

[exdeath]

You might want your spaceship to have wings if ever you had the want/need to enter a planets atmosphere...? Unless of course you ship operates in a self contained zero gravity field, then shape would not matter.

No. Space flight is all about mass to thrust ratios.

There are drastic compromises between takeoff weight, cargo lift capacity, flying in an atmosphere, getting into space, moving in space, reentry, and landing. All of these things have completely opposing design needs.

Example, the lift off portion of a spacecraft leaving a planetary surface has to be MASSIVE and it would have to haul that around even when not using it, requires more fuel, which requires more mass and bigger engine which requires more fuel for the big engines etc etc etc. The you add wings for atmospheric flight big enough to carry your already massive spacecraft and it starts all over. If it has to be capable of multiple reentries you are taking about massive heat shielding, more weight, bigger wings to fly in air, more fuel and bigger engines to start and stop in space, and so on and on. Operating in the gravity well of a planet? Stronger structures and useless mass that has to be accelerated with more fuel in space, further reducing cargo and lift capacity.

Vehicles designed for everything are inefficient and suck at everything and not only are they not practical , they simply aren't possible with current propulsion systems, energy constraints, and the need to carry massive amounts of energy deficient expendable chemical propellant mass.

Discarding boost stages of rockets and separate descent and ascent stages in the lunar landers, etc, all illustrate the all importance of mass vs thrust and limits of fuel capacity in space.

A small body like the moon with little gravity and no atmospheric drag is one thing. A large Earth like planet? Think about it. If it takes a Saturn V to launch 3 people in a tiny capsule off Earth, it will take the same thing to get OFF the destination planet and back. So now you need something big enough to launch an entire fully fueled Saturn V assembly into Earth orbit + get to the destination + have that entire Saturn V survive reentry, then launch again and back. And add wings and fly, and be able to do this multiple times all self contained in a single stage vehicle that doesn't shed mass. Yeah...no.

 

[exdeath]

Space shuttle doesn't produce lift and doesn't fly. It just falls inefficiently and non aerodynamically.


You could argue with enough angle of attack and thrust it could take off like a plane, but if we had infinite thrust and fuel economy to make *any* 2000 ton brick "fly" with lift and not thrust we wouldnt have the challenges we have.

Single stage to orbit atmospheric vehicles are currently a pipe dream and holy grail at the moment and generating tons of private sector interest.

Spaceship One is interesting when you consider the size of the shuttle's external fuel tank relative to the shuttle and realize how tiny Spaceship One's fuel capacity must be. They are barely aiming to one pump chump into low earth "orbit" for a few moments, still dragging in the upper atmosphere before falling again. So don't get TOO excited

 

[sdifox]

I'm surprised no one has posted this yet.

Hell, there is more than one of them.

Probably because they are not really spaceship, rather reentry vehicles.

 

[CZroe]

Probably because they are not really spaceship, rather reentry vehicles.

And any "space ship" with a similar requirement (controlled/piloted atmospheric use, reusable for re-entry OR flight) would need a similar design. All this talk about fuel and structure and propellant obviously ignores that these fictional vehicles have overcome these limitations with things like fusion, zero-point energy, and mass-less (or super-advanced ion-type) propulsion.

 

[skyking]

Space shuttle doesn't produce lift and doesn't fly. It just falls inefficiently and non aerodynamically.

It produces a great deal of lift, and uses conventional control surfaces to maneuver. It is flying as much as any aircraft with no thrust.

 

[Gunbuster]

Because actual space 'flight' mechanics would be boring. Even with thrust vectoring you wouldn't really turn, you'd just rotate around your center of mass until you're pointing the right way. You never cancelled out that original vector of travel. So you'd just be tumbling around in space. And nobody wants to watch a bunch of spinning pieces of metal for 2 hours.

Pretty much this! Accelerate towards enemy for a day, shoot laser at engagement range for 20 seconds as you fly past. Decelerate for a day. Accelerate back towards enemy for a day...

Or you drop a bunch of diamonds, tungsten, whatever as you approach with high velocity. Enemy poof dead from hyper-velocity impact.

 

[exdeath]

I believe an atmospheric air breathing rocket is the first step. A rocket that has an intake an compressor stage like a jet engine that is then able to switch to internal onboard oxidizer as it leaves the atmosphere. Carrying oxidizer is a huge mass component in bipropellant engines (bigger than the fuel tanks).

Problem is you need a LOT of oxidizer and the atmosphere just isn't that dense, compounded by the fact that it gets less dense very quickly with altitude. Compounded further that practical rocket fuel AFR requires more oxidizer than fuel. Oh, and unlike a tank of 100% pure liquid oxygen or nitric acid or whatever your onboard oxidizer is, air is only 20% or so oxygen.

 

[sdifox]

And any "space ship" with a similar requirement (controlled/piloted atmospheric use, reusable for re-entry OR flight) would need a similar design. All this talk about fuel and structure and propellant obviously ignores that these fictional vehicles have overcome these limitations with things like fusion, zero-point energy, and mass-less (or super-advanced ion-type) propulsion.

You don't design a big spaceship for re-entry, you equip them with small re-entry vehicles.

 

[sdifox]

I believe an atmospheric air breathing rocket is the first step. A rocket that has an intake an compressor stage like a jet engine that is then able to switch to internal onboard oxidizer as it leaves the atmosphere. Carrying oxidizer is a huge mass component in bipropellant engines (bigger than the fuel tanks).

Problem is you need a LOT of oxidizer and the atmosphere just isn't that dense, compounded by the fact that it gets less dense very quickly with altitude. Compounded further that practical rocket fuel AFR requires more oxidizer than fuel. Oh, and unlike a tank of 100% pure liquid oxygen or nitric acid or whatever your onboard oxidizer is, air is only 20% or so oxygen.

Only if you plan to only fly in atmosphere with high percentage of oxygen.

 

[Maximilian]

Wings are aesthetically pleasing is the top answer
A spaceship sized cue ball in space is hardly intimidating
Wings also provide hard points to mount forward facing weapon systems
And as mentioned if the ship plans to enter planetary atmospheres ala space shuttle

But yeah independence war had an awesome Newtonian physics engine. I miss that game so much.

You sure? :awe:

 

[exdeath]

Only if you plan to only fly in atmosphere with high percentage of oxygen.

Beat me before my edit. Theres that too.

 

[Scarpozzi]

You forget though, NASA hasn't had a manned craft to fly outside our orbit in many years. The Saturn V rockets were the last era of manned crafts that had the thrust and fuel capacity to travel from Earth to the moon in a timely fashion.

Rockets are practical, but not very reusable due to the spent fuel sections breaking off and becoming space-junk. This is why the shuttle program was a success...reusable craft. Hollywood and comics only try to keep up with the latest technology because it's just cooler. No one wants to see a Saturn V and it's tiny payload.....though they are probably the most amazing craft to ever come out of NASA. (thrust and fuel capacity are crazy on those things)

 

[sdifox]

You forget though, NASA hasn't had a manned craft to fly outside our orbit in many years. The Saturn V rockets were the last era of manned crafts that had the thrust and fuel capacity to travel from Earth to the moon in a timely fashion.

Rockets are practical, but not very reusable due to the spent fuel sections breaking off and becoming space-junk. This is why the shuttle program was a success...reusable craft. Hollywood and comics only try to keep up with the latest technology because it's just cooler. No one wants to see a Saturn V and it's tiny payload.....though they are probably the most amazing craft to ever come out of NASA. (thrust and fuel capacity are crazy on those things)

Shuttle program was a great PR success. Matter of fact is it would have been cheaper to keep using rockets since the refit the shuttle has to go through each time is super expensive.

 

[BurnItDwn]

This is why "Asteroids" is the best space shooter game of all time. They managed to get the physics right! (other than possibly the part with the whole teleporting across the universe at the "edge")

 

[exdeath]

You forget though, NASA hasn't had a manned craft to fly outside our orbit in many years. The Saturn V rockets were the last era of manned crafts that had the thrust and fuel capacity to travel from Earth to the moon in a timely fashion.

Rockets are practical, but not very reusable due to the spent fuel sections breaking off and becoming space-junk. This is why the shuttle program was a success...reusable craft. Hollywood and comics only try to keep up with the latest technology because it's just cooler. No one wants to see a Saturn V and it's tiny payload.....though they are probably the most amazing craft to ever come out of NASA. (thrust and fuel capacity are crazy on those things)

That "tiny payload" is exactly what the Saturn V was built to send to orbit.

Getting to the moon and back in the vacuum of space and in the relative absence of gravity isn't a big deal. Its getting a complete package capable of doing so into earth orbit in the first place.

The fact that the Saturn V was as massive as it was in order to do the latter says it was NOT a "tiny payload". The lift capacity of the Saturn V dwarfs anything the space shuttle could take to orbit. You are lifting essentially 4 fully fueled spacecraft into orbit at once (CM, SM, LM x 2 stages).

 

[Braznor]

For a ship using Newtonian/Einsteinian dynamics aka standard vector force thrusters, flying close at the speed of light will still require them to be in some form aerodynamic in terms of their design.

Remember at sufficient speeds very very close to the speed of light, any impact on the hull of such ships, even from mere individual atoms in the vacuum of space would prove catastrophic.

I heard that for a ship to travel conventionally close to the speed of light, it will need some form of shield and design which can protect it from collisions with mere individual atoms floating in the vacuum of space.

 

[skyking]

This is why "Asteroids" is the best space shooter game of all time. They managed to get the physics right! (other than possibly the part with the whole teleporting across the universe at the "edge")

the 2D part was a little simplistic as well

 

[exdeath]

Saturn V payload to orbit : 260,000 lbs

Saturn V payload to translunar injection: 100,000 lbs

Apollo command and service modules WITHOUT the 2 lunar lander stages, rover, etc : 66,000 lbs

Apollo with full moon mission with lander is around 100,000 lbs (all fully fueled for a moon round trip).

Empty space shuttle orbiter spacecraft weight without payload: 150,000 lbs (vs the Apollo spacecraft weight of 66,000 lbs and that's WITH payload to get to the moon and back where the shuttle has 0 fuel for its main engines after reaching earth orbit)

Space shuttle payload to orbit? A scant 50,000 lbs.

But its almost as big as a Saturn V and so much bigger than that "tiny" Apollo spacecraft and has a huge cargo bay...

Exactly. Remember what I said before?

Yeah, the space shuttle orbiter itself is all dead weight that subtracts from payload capacity. It wastes its launch propulsion lifting itself into space, instead of payload. It is terribly inefficient. This demonstrates exactly the principle I explained above.

That "tiny payload" of the Apollo is twice what the space shuttle can barely get to orbit, let alone into a translunar trajectory.

The important comparison is the actual space craft, and the reason a universal single stage to orbit, transatmospheric vehicle doesn't work:

Apollo, fully fueled and loaded to get to the moon and back (no lunar lander) 66,000 lbs

Empty space shuttle with no cargo, no onboard SSME fuel, just dead weight in orbit :150,000 lbs

In space economy, all your mass better be you, some food, and the rest fuel. The side effect is you lose mass burning fuel so its win/win. Anything else that isn't you, food, and consumable fuel, oh say like, AN ENTIRE AIRPLANE SHAPED 150,000 lb ORBITER that contributes absolutely nothing to either keeping you alive, or getting you to your destination, is dead weight.

 

[Gunbuster]

I heard that for a ship to travel conventionally close to the speed of light, it will need some form of shield and design which can protect it from collisions with mere individual atoms floating in the vacuum of space.

That's why in hard sci-fi you put a kilometer thick chunk of Ice at the front of the ship.

 

[Eureka]

That's why in hard sci-fi you put a kilometer thick chunk of Ice at the front of the ship.

I thought in hard sci-fi you don't travel relativistically. You sit six months in a metal tub to get to a moon of Saturn and then get your boot stuck in an ice puddle.

 

[Jeff7]

While we're looking at TV space physics: "Hiding in a nebula."
If you had a slice of a nebula in a jar on Earth, most people would consider it to be a vacuum.
Nebulas look all dense and dusty because they are huge. You might be looking through a few billion miles of very tenuous dust and gas. Whole star systems can form inside of them.
A starship that could see through Earth's atmosphere would have a breeze of seeing through a few thousand miles of nebula; certainly not enough to cause severe interference in futuristic sensors. I'm looking at you, flagship-of-the-fleet Enterprise. Maybe their CCDs are fabbed out of fubaritium.

Of course they need wings. That way they have more surface area per unit of volume, making them more vulnerable to enemy fire.

Doesn't matter. Bad guys can't hit anything anyway. Or if they are very skilled at aiming, their guns will jam. Star Wars taught us that even laser-based weapons can jam, even without the aid of raspberries.

Hangs in the air in precisely the same way that bricks don't.

Pretty much this! Accelerate towards enemy for a day, shoot laser at engagement range for 20 seconds as you fly past. Decelerate for a day. Accelerate back towards enemy for a day...

Or you drop a bunch of diamonds, tungsten, whatever as you approach with high velocity. Enemy poof dead from hyper-velocity impact.

Or just use electromagnetic beam weapons of various wavelengths. Phasers, lasers, masers, whatever. No need to do crazy maneuvering if you can just puncture their hull at the speed of light. Maybe try to slice off their wings, just to demoralize the pilot.

This is why "Asteroids" is the best space shooter game of all time. They managed to get the physics right! (other than possibly the part with the whole teleporting across the universe at the "edge")

Your scaling is off. The "asteroids" are masses of galactic superclusters. It really is wrapping around the Universe.

Good point.

I don't mind some stylistic design elements in spaceships, but most of the time they go overboard. It also matters what kind of scifi it is, too.

Star Wars: You've got C-3PO, a robot capable of speaking a few million languages, but then there's R2-D2, who only squeaks and beeps. A crappy ancient PC can at least synthesize Microsoft Bob's voice. Portable GPS or smartphones can synthesize something more reasonable than that. Couldn't they have just duct-taped a cellphone to his head, plug in a serial adapter, and have it translate?

They of course took a lot of liberties in that universe. "Light speed" can cross a galaxy in several hours. (Maybe it's actually Light Speed®.) TIE fighters use ion drives and solar panels. Even at 100% efficiency, solar panels aren't going to do much good in deep space. And I hope they have really good ion drives. Our ion drives fire out highly-accelerated xenon, and produce several dozen milliNewtons of thrust - maybe somewhere around an ounce, for a really good engine. Dogfights would take a very long time just to get going, and each overshoot would add weeks to the fight. And of course, the X-wings and A-wings have their "stabilizing" wings.

 

[Mermaidman]

These space SHIPS don't have wings: