Actually, as Robert Heinlein once said, “Once you’re in orbit, you’re halfway to anywhere”. Getting out of the gravity well of an Earth-sized planet is far more difficult than moving around the solar system; for one thing, once you’re in orbit you can do things gradually with gentle little nudges (like ion drives*) rather than having to go blasting off at 7 gs. Various plans for diverting an incoming Death Asteroid of Doom–more-or-less realistic plans, I mean, not “send guys up to blow it to smithereens with a really big nuke!”–rely on giving them relatively modest nudges (or even fantasically light nudges) over long periods of time.
Even if you want to build your gi-normous space structure in orbit around Earth itself, I suspect you’d wind up being better off importing materials in from someplace like the Asteroid Belt than trying to haul it out of our deep gravity well; and of course the Death Star could have been built smack in the middle of some convenient metal-rich asteroid belt in some out-of-the-way system someplace.
Of course with Star Wars there’s probably some techno-babble magic–antigravity, say–which renders the entire analysis moot.
*Real-life ion drives that is, which bear very little real resemblance whatsover to the “ion drives” casually mentioned in the Star Wars movies.
I wonder just how, structurally, the Death Star is held together. How do you build a sphere hundreds of kilometers across as a solid object? Either the main structure of the Death Star is built of fantastically strong fantastically rigid materials, or else relative to it’s size the Death Star is practically a liquid drop, only holding together because all stresses on it are distributed perfectly evenly.
The problem is compounded by the fact that the Death Star doesn’t seem to have any overall structural plan. What we see at the end of RotS and in RotJ is that the spheres appear to be being haphazardly constructed at the level of individual decks, with no larger superstructure evident. It would make a heck of a lot more sense if the Death Star had some primary structure defining its overall size and shape.
Not that I am anywhere near smart in this area, but wasn’t the Death Star just a big hollow ball that had a reactor in the middle, one center shaft (elevator?) going from top to bottom, and the just outer bridges going from the shaft to different levels?
The overall structure of it couldn’t be completely dense, otherwise it would be a shot put ball and have no purpose. I would assume that the station is basically more empty nothingness than actual materials.
Basically take 3,000 or so rings, place them all on top of each other connect them to a center stick by little decks, and there you have your very own Death Star
I think this is a key point. The Death Star is built around the superlaser and the reactor. Everything else is either to support the superlaser or to protect the superlaser. All those turbolasers and ion cannons and TIE fighter hanger decks and stormtrooper barracks are secondary weaponry.
And we see several times in the films that the Death Star has vast void areas, it shouldn’t be too much of a stretch to imagine that there are even bigger voids that we never see.
And don’t forget that antigravity is simple, rugged and dirt cheap in the Star Wars universe. Cheap droids float around, farmboys have floating speeders, and it’s all completely unremarkable. And of course, every space ship has gravity generators so the crew can walk around. So it isn’t a stretch to imagine that really big structures like the Death Star could be held together with gravity generators more than by steel beams. Every crew-accesible deck of the Death Star simulates normal gravity anyway, right?
So estimates of the amount of structural steel used in the Death Star could be off by an order of magnitude or more.
Let’s try to create a realistic figure by analogy and scaling up. The closest real-world equivalent to the Death Star would be a battleship. An Iowa-class battleship cost $125,000,000 to build in 1942. That’s the equivalent of $1,660,000,000 in 2008 dollars.
7200 trillion cubic meters is the equivalent of 1860 trillion tons in shipping gross tonnage. The Iowa was 45000 tons so the Death Star would be the equivalent of 41,000,000,000 Iowas. The cost would be $68,000,000,000,000,000,000.
Excellent, a (wo?)man after my own heart! Good job using completely made-up numbers and uncalled-for analogies to justify your expense estimates, just like I did! The only thing you forgot to do was to make a completely dumb math mistake, like mixing up radius and diameter or something.
In the game, “Force Unleashed”, there is a planet ‘Raxus Prime’, which is a junkyard planet. They have a facility there that is building a Mammoth Star Destroyer. The delivery mechanism to get the materials from the planet’s surface to the Star Destroyer is a massive railgun firing balls of molten metal about 100 yards across every two or three seconds up into orbit.
As for tidal forces, the Death Star isn’t very dense compared to its overall diameter.
As an aside, one of the most interesting aspects about the game Eve Online is that you actually have to go through the process of building the ships. The Massive Capital ships which are more on the scale of like the Battlestar Galactica than even a Star Destroyer, are built out of parts which are built out of minerals and other materials. Every step of the way, except the design of the blue print the building process is player controlled. To build such a thing you can’t just have a blue print but you also have to have the ability to acquire particular materials, which means catalyzing reactions for rare materials, refining ore into basic materials. ‘Tritanium’, is kind of the catchall mineral that is a stand in for ‘Metal’. If you wanted to build every step in the process to build a capital ship you would need multiple player owned stations, which means being able to control solar systems and defend them. You need a fleet of miners, industrial producers, haulers and a Combat Navy to man and defend your capital ship facility, your catalyzing reactors and such. Of course parts of the process can be purchased from vendors, you can buy capital ship parts that are already constructed, but you still have to ship them out to your capital shipyard. Shipping capacity basically comes in one of two forms, an Industrial Hauler which carries between 5000 and 40,000 m3 of cargo, or a freighter which carries between 700k and 1m m3.
Obviously the Empire has the full logistical infrastructure of the empire with which to build a mobile space station. It’s possible that parts of the Death Star were built by subcontractors under false pretenses, and delivered by freighter to the capital shipyards out in the remote system in which it was built. The laser crystals involved in the giant laser that destroys Alderaan could be justified as mining lasers, they could have whole deck subsections justified as what they are, a part for a space station. Only the macro assembly really need take place at the final shipyard.
If people would like to see more of what the interior of the Death Star looks like play Force Unleashed, there is a level where you run around inside the Death Star.
Even easier. Build a giant beach-ball in space. Inflate it. Then clad it with whatever superstructure and internal fittings and mountings you need - a few decks and elevators - and fit it with a reactor, drive, and a big-arse death ray. The last things you add are a command deck, crew quarters, hangars and the like. You don’t need to build the thing like you would a battleship.
A page full of pointless mathematical analysis to compare the cost of building a WWII battleship to a giant Star Wars spaceship - and you have to ask if I’m a guy?
OK, here’sI read a book a number of years ago about the feasibility of manufacturing in space that had some great techniques that could be used to build the Death Star.
To build a giant sphere in space: first, construct one or more giant lenses in space, and we mean giant, but won’t be expensive because no gravity. Now haul a nickel iron meteor in from the asteroid belt. Run it into the focus of the giant lens(es) where it will melt or evaporate or whatever depending on how you have the lenses set. In this case, we want “liquify.” Inject a gas into the molten ball of liquid nickel-iron and continue to do so, until you have your giant sphere. When it’s at the right size, send it out of the focus of the lenses. Voila, giant sphere.
Pointless nitpick: Luke points at the fleeing TIE fighter and says, “He’s heading for that small moon.”
To which Obi-Wan replies, “That’s no moon, it’s a space station.”
Han was surprised by the debris field of what had once been Alderaan. Which he quite rightly identified as an ‘uncharted asteroid field’ or something. I mean, until Tarkin blasted Alderaan to hell, there wasn’t an asteroid field in the system. At least not in Alderaan’s orbit.
Murphy’s Rules of Combat, #18: Never forget your weapon was made by the lowest bidder.
It’s actually going to be way cheaper to mine the materials in space and then mill them, assuming that you already have an infrastructure in space that can support habitation and industry. Lofting mass from ground to orbit is incredibly expensive, complicated, and prone to failure. Even in the seemingly free energy economy of Star Wars it’s going to be easier. Building a mill in space isn’t actually that difficult; the greatest difficulty is handling material in free fall, which can probably be best done by centrifugal motion and pressure/extrusion to keep it from spilling freely.
However, permit me to point out that the presumption here is that the Death Star is built of iron, nickel, and aluminum alloys. This may indeed be the case, especially given the sort of retro nature of the Star Wars universe, but it might also be auto-fabricated out of some nano-crystalline structure (which would explain the durability of vessels subject to multiple impacts and energy blasts), heavy-duty organic or long chain silicon molecules, or any of a number of other materials. It is also not the case, as with a terrestrial structure, that it need to be compressively self-supporting. As R. Buckminster Fuller frequently preached, an essentially hollow sphere of any size can be self-supporting by using a geodesic substructure, and the larger you make the sphere the less structure per unit surface area is needed to support it. The use of artificially generated gravity within the Death Star complicates things somewhat insofar as we don’t really know how this is tied into or what impact it may have on the overall structure, but I think we can safely assume that the gravity and inertial control technology would permit an essentially free floating interior structure that does not draw on the outer shell.
Personally, if I were going to build something on the scale with something akin to conventional technology I would eschew a metallic structure at all in favor of a fiber-wound reinforced water ice shell, which would provide a compressive strength-to-weight ratio on the same order of magnitude as steel while allowing greater tensile strength, ablative protection, repair and expandability, and ready use of available interplanetary materials. You could make a station the size of a small moon–say, 50 km diameter–with the materials from a single large comet. Stick a solar collector/reflector on one end would permit acquiring power from the local star system (lacking, as we currently do, a compact efficient power source sufficient to provide input to a large projected energy weapon) which could then be stored in some kind of excimer in a Rydberg matter field, which could then be coupled to a ground state to provide quick input to a gigawatt-class laser, p-beam, or plasma weapon; not enough to destroy a planet, but given a judicious selection of frequency or output energy level you could lay waste to entire swaths of occupied surface area or destroy an incoming attacker.
Yeah, but they’re pretty compact in their frozen state. And I understand most comets are nothing but that stuff – methane, ammonia, water ice, etc. Prolly lot of meteors are the same, too. Just send 'em in along with the nickel-iron meteors and you’ve got your inflation gas.
