Interstellar Space Travel Is Possible In Our Lifetime, Here's How (As Seen In Avatar) Pics - General

Interstellar space travel, of the kind featured in James Cameron's Avatar, is possible within our lifetimes. Here's how we can do it with current technology, tweaking technology we already have and utilizing technology we're on the cusp of mastering. By interstellar travel, I don't mean travelling to the ends of the galaxy.[b] A one way unmanned trip to the nearest star system, Alpha Centauri, would take roughly five years cruising at 70% the speed of light, a manned return trip would take ten years. Exploration of a few dozen other nearby star systems would also be possible with Voyager-type robotic missions.[/b] The only thing hampering these designs is astronomical cost. It would be worth it though. Here is a theoretical project. (DETAILED DIAGRAMS BELOW) [b]**For the too long; didn't read crowd: Journeys to the nearest star systems are possible a lot sooner than you think, but space travel will probably never be how people imagine it.[/b] ---------------------------- From Project THRO The starship ISV Venture Star from the movie Avatar is one of the most scientifically accurate movie spaceships it has ever been my pleasure to see. When I read the description of the ship, I got a nagging feeling that something was familiar. A ship with the engines on the nose, towing the rest of the ship like a water-skier? Wait a minute, that sounds like Charles Pellegrino and Jim Powell's Valkyrie starship. Well, as it turns out, there was a good reason for that. James Cameron likes scientific accuracy in his movies. So he looked for a scientist who had experience with designing starships. Cameron didn't have to look far. As it turns out he already knew Dr. Pellegrino. This is because Dr. Pellegrino had worked with Cameron on a prior movie, since Dr. Pellegrino is one of the worlds greatest living experts on the Titanic. [IMG]http://i28.tinypic.com/2d7dbut.jpg[/IMG] [IMG]http://i28.tinypic.com/335fket.jpg[/IMG] In the upper diagram is a green arrow at the ship's nose, indicating the direction of flight. The ship is 1.5 kilometers long. In the Sol departure phase, a battery of orbital lasers illuminates a 16 kilometer diameter photon sail attached to the ship's nose (sail not shown). A mirror shield on the ship's rear prevents the laser beams from damaging the ship. The lasers accelerate the ship at 1.5 g for 0.46 year. At the end of this the ship is moving at 70% the speed of light (210,000 kilometers per second). Keep in mind that battery of orbital lasers is going to have to be absolutely huge if it is going to push a lightsail at 1.5 g. This is not going to be a tiny satellite in LEO. I cannot calculate the exact power rating since figures on the mass of the ISV Venture Star are conspicuous by their absence. The equation is Vs = (2 * Ev) / (Ms * c) where Vs is the starship acceleration, Eb is the energy of the beam, Ms is the mass of the starship, and c is the speed of light in a vacuum. Dr. Geoffrey Landis says is boils down to 6.7 newtons per gigawatt. In Dr. Robert Forward's The Flight of the Dragonfly (aka Rocheworld), his starship's light sail is illuminated by a composite laser beam with a strength of 1500 terawatts. This pushes the starship with an acceleration of 0.01g (about 150 times as weak as the acceleration on the Venture Star). The beam is produced by one thousand laser stations in orbit around Mercury (where solar power is readily available in titanic amounts). Each station can produce a 1.5 terawatt beam, 1500 terawatts total. By way of comparison, in the year 2008, the entire Earth consumed electricity at a rate of about 15 terawatts. Since the Venture Star appears to be more massive than Forward's starship, and is accelerating 150 times as fast, presumably its battery of laser cannons is orders of magnitude larger. As a side note, it is good to remember Jon's Law for SF authors. and The Kzinti Lesson. While technically this laser array is a component of a propulsion system, not a weapon; in practice it will have little difficulty vaporizing an invading alien battlefleet. Or hostile human battlefleet, for that matter (with the definition of "hostile" depending upon who actually controls the laser array). As Commander Susan Ivanova said in the Babylon 5 episode Deathwalker: "Our gun arrays are locked on to your ship, and will fire the instant you come into range. You will find their firepower most impressive ... for a few seconds. " Anyway, after the laser boost period is over, the sail is then collapsed along molecular fold lines by service bots, and stowed in the cargo area. The ship then coasts for the next 5.83 years to Alpha Centauri. [IMG]http://i28.tinypic.com/348r9j4.jpg[/IMG] [IMG]http://i26.tinypic.com/331iqgz.jpg[/IMG] [IMG]http://i25.tinypic.com/66zo8h.jpg[/IMG] [IMG]http://i32.tinypic.com/33uzm07.jpg[/IMG] There are no batteries of laser cannon at Alpha Centauri so the lightsail cannot be used to brake to a halt. Instead, the twin hybrid fusion/matter-antimatter engines are used. These engines are not used for the Sol departure phase because that would increase the propellant requirement by about four times with a corresponding decrease in cargo capacity. The engines burn for 0.46 year, producing 1.5 g of thrust, thus braking the ship from a velocity of 70% c to zero. Matter and antimatter is annihilated, and the energy release is used both in the form of photons and to heat up hydrogen propellant for thrust. A series of thermal shields near the engines protect the ship's structure from the exhaust heat. The engines are angled outwards a few degrees so that the exhaust does not torch the rest of the ship (exhaust path indicated in diagram by red arrows). This does reduce the effective thrust by an amount proportional to the cosine of the angle but is acceptable. Why is most of the ship behind the engine exhaust? Because this reduces the mass of the ship. And when you are delta-Ving a ship up to and down from 70% c, every single gram counts. Conventional spacecraft have the engines on the bottom and the rest of the ship build on top like a sky scraper. This design has the engines on the top and the rest of the ship is dragged behind on a long tether (the "tensile truss" on the diagram). The result is a massive reduction in structural mass. The engines are topped by monumental heat radiators used to get rid of waste heat from the matter-antimatter reaction. According to the description, after the burn is finished, the radiators will glow dull red for a full two weeks. [IMG]http://i32.tinypic.com/2ahwj0n.jpg[/IMG] [IMG]http://i26.tinypic.com/2jb6wra.jpg[/IMG] [IMG]http://i27.tinypic.com/24pm3nn.jpg[/IMG] Immediately stern ward of the engines is the cargo section. It is arranged in four ranks of four modules each. Each module contains 6 cargo pods. A mobile transporter with a long arm moves within the cargo section in order to load and unload the shuttles. [IMG]http://i30.tinypic.com/2ue1e6x.jpg[/IMG] Next comes Two Valkyrie trans-atmospheric vehicles, aka "surface to orbit shuttles." They are docked to pressurized tunnels connected to the habitation section. Each is capable of transporting either [a] the contents of two cargo pods and 100 passengers or the contents of six cargo pods and no passengers. [IMG]http://i32.tinypic.com/350kytg.jpg[/IMG] [IMG]http://i32.tinypic.com/in7tp3.jpg[/IMG] Next come the habitation module. This holds the passengers in suspended animation for the duration of the trip. This is constructed almost totally from non-metallic materials, to prevent secondary radiation from galactic cosmic radiation. The habitation module's life support system can only support all the passengers being awake for a limited time. There is no problem for the short period when the passengers are woken up and shuttled to the planet's surface. However, if the suspended animation system malfunctioned half-way through the multi-year voyage, life support could not handle it. In these case, the passengers would be "euthanized" instead of being awakened. [IMG]http://i30.tinypic.com/1z2gmjo.jpg[/IMG][IMG]http://i27.tinypic.com/5oik2t.jpg[/IMG] Next is the two on-duty crew modules. These are spun on the ends of arms to provide artificial gravity. When the ship is under thrust, the spin is taken off, and the arms are folded down along their hinges so that the direction of gravity is in the proper direction. [IMG]http://i25.tinypic.com/33azat1.jpg[/IMG] Finally comes the shield. While the ship is being boosted by the laser batteries, the shield protect the ship (but not the sail) from the laser beams. After boost, while the ship is coasting at 70% c, the ship is rotated so that the shield is in the direction of travel. The shield is constructed as a Whipple shield, and protects the ship from being damage by grains of dust. At 70% c relative, each dust grain would have 4,900,000,000 freaking Ricks of damage. This means a typical interstellar dust grain with a mass of 4 x 10-6 grams will hit with the force of 20 kilograms of TNT, or about the force of four anti-tank mines. When the ship wants to depart Alpha Centauri and return to Sol, it re-fills its antimatter and propellant tanks from the local fueling stations, uses the matter-antimatter engines to boost up to 70% c again, coasts for five-odd years, and is decelerated to a halt by the laser batteries at Sol. ----------------- Common Space Travel Misconceptions: [u]Space Is Not An Ocean[/u] Far too many SF shows make the scientifically inaccurate assumption that space travel will be just like ocean travel. This is very wrong. In particular, space is not two-dimensional, there is no friction in space, and spacecraft will not have their decks laid out as if they were seagoing vessels. More debatably, spacecraft classes will probably not be named after naval ship classes (e.g., Cruiser, Battleship, Destroyer, Frigate, etc.), the military rank structure will probably be more like the Air Force instead of the Navy, and space pirates are highly unlikely. [u]Rockets Are Not Boats[/u] With a scientifically accurate rocket, the direction of "down" will be in the same direction that the rocket exhaust is shooting. In other words, a spacecraft will have the general internal arrangement of a skyscraper, not that of a passenger airplane. The floors will be set perpendicular to the axis of thrust, and "up" will be the direction the spacecraft is thrusting. This is one of the most persistent misconceptions, due to the unfortunate fact that practically all spacecraft in SF media get it wrong. I'm looking at YOU Star Trek, Star Wars, and Battlestar Galactica! This bad trope is an outgrowth of the "space is two dimensional" fallacy. Some SF shows go so far bad that they make their spacecraft like boats. Even to the point of stupidly placing the ship's Bridge perched on the "top" where it will be shot off by hostile weapons fire, instead of deep in the core of the ship where it will have some protection (Star Trek and Uchuu Senkan Yamato immediately come to mind). (Anthony Jackson points out two exceptions. One: if your spacecraft is also part aircraft, like the Space Shuttle, in the air "down" will be perpendicular to the wings, but in space "down" will be in the exhaust direction. Two: if you have an ion drive or other low-thrust drive, the ship will probably have some kind of centrifugal gravity, so "down" will be radial to the axis of spin ) [u]Rockets Are Not Fighter Planes[/u] It is impossible to make swooping maneuvers without an atmosphere and wings. You also cannot turn on a dime. The faster the ship is moving, the wider your turns will be. Your spacecraft will NOT move like an airplane, it will act more like a heavily loaded 18-wheeler truck moving at high speed on a huge sheet of black ice. There is also some question of whether space fighters make any sense from a military, scientific, and economic standpoint. And another thing: if you maneuver, you are NOT going to be slammed into walls by high gee forces like a NASCAR race car driver. It doesn't work that way unless you have an atmosphere and wings. The only thing you will feel is a force in the same direction that the rocket exhaust is shooting, which will be equal to magnitude to the acceleration the engine is producing. Since Rockets Are Not Boats, the force generally be in the direction the crew considers as "down", as defined by the rocket's design. It will never be "sideways" (except under silly situations, like occupying a spinning centrifugal gravity ring while the rocket is accelerating). It doesn't matter if you are thrusting in some other direction that the rocket's direction of travel (see Rockets Are Not Arrows) nor does it matter the rocket's current velocity (relative to what?). If the rocket engine cannot proved more than 0.5 gs of acceleration, the crew is never going to feel more than 0.5 gs of acceleration. Even if the ship is moving at a large fraction of the speed of light. [u]Rockets Are Not Arrows[/u] Spacecraft do not necessarily travel in the direction their nose is pointing. During an engine burn the thrust will be in the direction of the nose. But once the thrust is off, the ship can turn to any orientation. It can fly "sideways" through space if it wants. This can be important during space combat, in order to get your ship's weapons to bear on the enemy. So all those scenes from Star Wars and the old Battlestar Galactica where a hapless space fighter cannot shake the enemy on their tail are utter bilge. All they have to do is spin on their short axis and blast the tail-gater. (For a good example watch the Babylon 5 episode "Midnight on the Firing Line") [u]Rockets Got Wings[/u] If your rocket has a multi-megawatt power plant, an absurdly high thrust thermal rocket propulsion system, or directed energy weapons it will need huge heat radiators to purge all the waste heat. Otherwise the rocket will melt or even vaporize. Radiators look like large wings or arrays of panels. The necessity of radiators a real problem for warships since radiators are pathetically vulnerable to hostile weapons fire. [u]Rockets Don't Got Windows[/u] Spacecraft have no need of windows or portholes, for much the same reason as a submarine. (No, the Seaview doesn't count. Strictly science fiction. There are no panoramic picture windows on a Trident submarine). Windows represent structural weakness, and there really isn't much to see in any event. Unless the spacecraft is orbiting a planet or docking with another ship, the only thing visible is the depths of space and the eye-searing sun. And unlike submarines, windows on a spacecraft also let in deadly radiation. Star Trek, Star Wars, and Battlestar Galactica to the contrary, space battles will NOT be fought at a range of a few feet. Directed energy weapons will force ranges such that the enemy ships will only be visible through a telescope. Watching a space battle through a port hole, you will either see nothing because the enemy ships are too far away, or you will see nothing because a reflected laser beam or nuclear explosion has permanently robbed you of your eyesight. The navigation room might have an astrodome for emergency navigation. But for the most part windows will be omitted in favor of radar, telescopic TV cameras, and similar sensors. [u]There Is No Friction In Space[/u] There is no friction in space. Here on Terra, if you are driving a car and take your foot off the accelerator, the car will coast to a stop due to the friction of the road. In space, if a ship turns off its engines it will maintain its current velocity for the rest of eternity (unless it crashes into a planet or something). In the movie 2001 A Space Odyssey, you may have noticed that the spacecraft Discovery was traveling to Jupiter with nary a puff coming out of the rocket motors. This is why it makes no sense to talk about the "range" of a rocket. Any rocket not in orbit around a planet or in the Sun's gravity well has a range of infinity. In theory it can do a burn and travel to, say, the Andromeda Galaxy, it is only that it will take millions of year to get there. Instead of a rocket's range, one should talk about a rocket's delta V capacity. Acceleration and deceleration are symmetrical. This means if your spacecraft spends an hour accelerating to a speed of 1000 meters per second, it is going to take roughly another hour to decelerate to a stop. You cannot "put on the brakes" and suddenly stop, like you can do with a boat or an automobile. (I say "roughly" because as you accelerate your ship looses mass due to expending reaction mass, so it becomes easier to decelerate. But this is a complicating detail you can ignore for now) If you want to get an intuitive feel for how spacecraft move, I would suggest playing one of the few accurate spacecraft simulation games available. There are a few suggestions here. [u]Fuel Is Not Propellant[/u] In a rocket, there is a difference between "fuel" and "reaction mass." Rockets use Newton's third law of Action and Reaction in order to move. Mass is violently thrown away in the form of the rocket's exhaust and the reaction accelerates the rocket forward. This mass is of course the "reaction mass." It is sometimes also called "remass" or "propellant." The "fuel" is what is burned or whatever to generated the energy to expel the reaction mass. For example, in a classic atomic rocket, the fuel is the uranium-235 rods in the nuclear reactor, the reaction mass is the hydrogen gas heated in the reactor and expelled from the exhaust nozzle. There are only a few confusing cases where the fuel and the reaction mass are the same thing. This is the case with chemical rockets such as the Space Shuttle and the Saturn 5, which is how the misconception started in the first place. Automobiles, airplanes, and boats are sizable vehicles with relatively small fuel tanks. Not so rockets. An incredibly powerful rocket might approach having half its mass composed of reaction mass and the other half structure, hull plates, crew members, and everything else. But it is more likely that 75% of the mass will be reaction mass. Or worse. Most rockets are huge propellant tanks with a rocket engine stuck on the tail and a tiny crew habitat stuck on the top. [u]There Ain't No Stealth In Space[/u] In space, there is no practical way to hide your military spacecraft from detection by the enemy. [u]Mass Is Not Weight[/u] There is a difference between weight and mass. An object's mass is always the same, but an object's weight depends upon what planet it is sitting on. A brick with a mass of one kilogram will have a weight of 9.81 newtons (2.2 pounds) on Terra, a weight of 1.62 newtons on Luna (0.36 pounds), and a weight of zero newtons (0 pounds) on the International Space Station. But in all cases it's mass will be the same: one kilogram. (Chris Buzon points out that if the object is moving at relativistic velocities relative to you, you will measure a mass increase. But this is not noticeable at ordinary relative velocities.) The practical consequence is that if you are in a spacesuit on the Space Station, you cannot move everything by tapping it with your pinky finger (you may start it moving at a rate of one millimeter per week, but that is close enough to "cannot" for government work). The Space Shuttle may be floating next to the station with a weight of zero, but it still has a mass of 90 metric tons. If it is stationary and you pushed on it, there will be very little effect (in fact, about the same effect as if the Shuttle was sitting on the tarmac at Cape Kennedy and you gave it a shove). And if it is moving slowly on a collision course with the station, and you are in between, the fact that it has zero weight will not prevent it from crushing you like a bug despite your attempts to stop it. It takes just as much energy to stop an object as it took to start it moving. Sorry, but your orbital construction crews will NOT be able to manually manipulate multi-ton girders like they were toothpicks. The other factor to consider is Newton's Third Law. If you push on a girder, there will be both action and reaction. Since the girder has more mass, it will start moving a microscopic amount. But since you have less, you will start moving in the opposite direction with much more velocity. This renders many common tools unusable in the free fall environment, such as hammers and screwdrivers. [u]Space Is Three Dimensional[/u] Space is three dimensional, not two dimensional. This bad trope is an outgrowth of the "space is an ocean" fallacy. Spacecraft are not limited to moving on a surface like a boat, they can go "up" and "down." They are not even limited like a aircraft, the latter is limited to how far up and down they can go. A spacecraft can theoretically fly to infinity in any given direction. There is no limit on their orientation either. If you saw the Starship Enterprise approaching the Starship Intrepid and one was "upside down" with respect to another, you might think this was wrong but in reality there is nothing preventing this. Even worse: the nose of the other spacecraft might not even be pointed in the direction the ship is flying. This makes unloading a broadside on an enemy spacecraft much more challenging. They can approach you from any direction, not just in a two dimensional plane. ----------------------- An interesting article for anyone who's interested: [url]http://www.cracked.com/article_18547_6-reasons-space-travel-will-always-suck.html[/url]

:psyduck:

:psyboom:

:derp: [editline]10:34PM[/editline] Fucking hell, how many times did you watch AVATAR?

Is that the eiffel tower on one of those? Not too sure the French would be willing to lend that to you.

[url]http://projectrho.com/rocket/[/url] I used it as a source a billion times, but hey at least tell us you did or instead of copy-pasting everything write it again yourself, even if it presents p. much the same info, the way you write it will present it in a different, more summarized way. EDIT: Oh God disregard that I'm an idiot. I read "Project THRO" but didn't associate it with the Atomic Rockets website since it's usually just "Atomic Rockets" and I'm used to reading "Project Rho".

:bang:

rated informative

@To those who rate informative and leave: It's a good read. [IMG]http://www.charlespellegrino.com/img/cp_face.jpg[/IMG] [B][I]THIS THREAD IS CHARLES PELLEGRINO-APPROVED[/I][/B]

Why is the whole thing bolded Edit: Okay it's fixed now. Kinda interesting.

see kids? this is what you can do with a degree in science instead of flipping burgers!

Those ships better have extremely precise alignment navigation. If you miss the decceleration laser batteries on either end, you're fucked. [QUOTE]If the suspended animation system malfunctioned half-way through the multi-year voyage, life support could not handle it. In these case, the passengers would be "euthanized" instead of being awakened.[/QUOTE] That could be a problem...

[QUOTE=woodlander;23688398][b] Space is three dimensional, not two dimensional. Spacecraft are not limited to moving on a surface like a boat, they can go "up" and "down."[/b][/QUOTE] [img]http://theinfosphere.org/images/6/64/Free_Waterfall%2C-Sr..jpg[/img] I did not know this.

Why did you bold the whole post.

That's why it's called science [b]fiction[/b].

but but I like the way the ships look in sci-fi movies they are so much nicer and sleeker looking.

Project Valkyrie can reach 92% light speed actually, but the engineering it would take to make the fuel for it would be crippling for earth for little to no return. It's a shame but until we have a space based economy we ain't doing shit.

Rocket science

[QUOTE=nikola631;23690023]but but I like the way the ships look in sci-fi movies they are so much nicer and sleeker looking.[/QUOTE] nicer and sleeker means added weight for little to no reason which means more fuel is needed. Inefficient! :science:

All these pictures are from Avatar.

You forgot that not every spacecraft is a rocket of some sort. There are other theoretical ways to travel, not that any of the are particularly feasible.

[QUOTE=OogalaBoogal;23690203]All these pictures are from Avatar.[/QUOTE] [quote]As seen in Avatar[/quote]

[QUOTE=bravehat;23690141]nicer and sleeker means added weight for little to no reason which means more fuel is needed. Inefficient! :science:[/QUOTE] But weight means nothing during space travel. :eng101:

[QUOTE=mrcole92;23690451]But weight means nothing during space travel. :eng101:[/QUOTE] Mass does.

[QUOTE=mrcole92;23690451]But weight means nothing during space travel. :eng101:[/QUOTE] Mass does :science:. But in science [b]fiction[/b] looks are more important.

I'm not sure what to say. What I am thinking about saying, though, is that I doubt any of this will work like Avatar or the guy who wrote the article states, at least, not exactly. I'm fairly certain that the world's greatest scientists who work on this kind of stuff every day and who haven't figured this out yet will before James Cameron and a bunch of film goons will.

[QUOTE=mrcole92;23690451]But weight means nothing during space travel. :eng101:[/QUOTE] Mass does, and I suppose depending on vicinity to a planet or gravity well weight would too. Very much. Try F=ma with a 1,000,000 Kg ship with 1000 newtons of force and see how fast it accelerates. Then do it with a 10,000 Kg ship The only thing space does is reduce the amount of drag and resistance on the craft, it still requires a massive amount of force to move stuff, the laws of physics don't just stop when you leave the atmosphere.

[QUOTE=Detective P;23690573]I'm not sure what to say. What I am thinking about saying, though, is that I doubt any of this will work like Avatar or the guy who wrote the article states, at least, not exactly. I'm fairly certain that the world's greatest scientists who work on this kind of stuff every day and who haven't figured this out yet will before James Cameron and a bunch of film goons will.[/QUOTE] Cameron didn't design it, he hired Charles Pellegrino to do that. The ship IS an actual Valkyrie rocket. In reality it would look like this: [IMG]http://g-ecx.images-amazon.com/images/G/01/ciu/32/1c/fceea2c008a05f89a3fa5010.L.jpg[/IMG] And yes he's one of the world's greatest scientists.

Rated rainbow because you watched too much avatar.

[QUOTE=Detective P;23690573]I'm fairly certain that the world's greatest scientists who work on this kind of stuff every day and who haven't figured this out yet will before James Cameron and a bunch of film goons will.[/QUOTE] Cameron worked with people who do work on this stuff everyday.