How large could a weapon based on lightsaber technology be? Could one be designed for ship based attacks i.e. a lightsaber ram.
Would there be power issues with this or would the crystal size be the biggest problem? I assume that while there would be difficulties getting a big enough natural crystals, as favoured by the Jedi, there would be no problem creating a large enough synthetic crystal.
Yes, in that that’s precisely what the Death Star is: a weapon based on kyber crystals, the primary component of lightsabers, that is capable of firing from one ship (the Death Star) at other vessels, as well as planets.
No, most likely, in the sense that the question supposes, i.e. as a lightsaber ram.
A lightsaber would need to be large to be an effective weapon (to be able to impale a ship without literally crashing into it, for example). The larger the lightsaber, the more energy would be needed to power it. It’s possible that the energy demands would prove too cumbersome, or that it might be more efficient just to create a Death-Star-style turbolaser.
It’s not clear that the properties of lightsabers can be replicated. The Force may be involved:
The energy potential was a given; his team had proven as much in their earliest piezoelectric experiments. But an ignition facility or a power plant would have to be more than an enormous lightsaber, which, in addition to housing a crystal, was believed to incorporate an emitter matrix, modulator circuitry, plasma, and a superconductor that channeled energy back to the negative pole of the lightsaber’s hilt. By rights lightsabers shouldn’t have been able to cut through meter-thick durasteel and yet they could, which lent credence to the notion of their being augmented by the Force itself.
Acting through the kybers?
Catalyst: A Rogue One Novel
Since the response of the kyber crystals depends on the person interacting with them (e.g. Sith bleeding their crystals to make them red, crystals calling to their chosen wielders), it can’t be certain that a kyber crystal weapon would work for just anyone. Galen Erso was successful, but how much of that was personal?
One might imagine that synthetic crystals would work, but in current Disney canon synthetic crystals are bad news (i.e. highly unstable), and would probably be more likely to blow up both ships.
In The Phantom Menace we see Qui-Gon attempt to cut through a blast door with his lightsaber. It isn't a particularly speedy process and he doesn't attempt to cut through any of the hull material around the door either.
Furthermore in The Empire Strikes Back Luke uses his lightasber to destroy a control panel to open a door rather than simply cut through the hull of the AT-AT which appears to be a heavily armoured vehicle.
However lightsabers seem to have no trouble cutting through smaller lighter materials - guardrails, speeder control vanes, and so on.
From that I think that we can safely deduce that a lightsaber is not a very effective weapon against starships compared to a blaster even assuming that they could be mass produced or sized up as starship weapons.
Secondly, the only lightsabers we see in film canon are in the hands of Jedi and each lightsaber appears to be unique and individually crafted. All of which implies that they are rare and probably difficult to manufacture, possibly only by someone with Force abilities.
Thus the answer to can a starship sized lightsaber be manufactured is almost certainly no, it cannot. However this theory is only supported by the absence of such weapons and the points above.
Most Jedi (every one I've seen depicted or read about) are bipedal, can turn on a dime, and are capable of movement on complex axis. Ships in space can go forward, sometimes backwards, and can tilt on a few axis, in a manner similar to aircraft. They behave slightly different without gravity and air resistance though. For capital ships, the dynamics are closer to a hybrid of naval vessels and planes.
Since a light Sabre is similar to a sword, and a space ship is similar to either a fighter jet or a naval ship, the answer can partially be attributed to the fact that there is no real life example of a sword being attached to real fighter jets or navy ships. Scifi battles tend to use tactics adapted from real life militaries,
Blasters are simpler and your able to fire at long-range and not get too close to a target.
