Star Wars: A New Hope was a massive success when it hit cinemas back in 1977. It was a groundbreaking sensation in the field of science fiction movies and computer generated imagery (CGI) in films. What really caught many fans’ eyes was, of course, the lightsaber. Also referred to as a “laser sword”, it is described as “an elegant weapon, for a more civilised age”. Now in our civilised age, we have decided to replicate this dangerous weapon. Lightsabers have already been built by a few enthusiasts. For this piece, we will be focusing on Hacksmith Industries’ lightsaber build from 2020, as it is the closest to the real deal.
Fig. 1. “Hacksmith Industries’ latest lightsaber build”, Hacksmith Industries, 4000° PLASMA PROTO-LIGHTSABER BUILD, 2020.
Hacksmith Industries was founded by James Hobson, an engineer who builds real-life versions of film and video game gadgets. After multiple attempts, the team managed to fabricate a retractable, plasma-based lightsaber. However, this is not a real lightsaber, but more-so a protosaber in the Star Wars universe. We will get back to this point later on.
How do they work?
Let us first talk about how lightsabers work in the movies. A lightsaber consists of three parts: the hilt, the Kyber crystal and the blade itself. Similar to a traditional sword, the hilt is the handle and is made of a durable metal such as aluminium. It contains the Kyber crystal, which is a rare crystal found in the Star Wars universe and is the power source of the lightsaber.
Moving onto the more interesting part, the blade is a beam of plasma. Often called “the fourth state of matter”, it is created by heating gas up to temperatures as high as 2,500 degrees celsius. A battery inside the hilt activates the crystal. The produced plasma is then focused through a lens and directed outwards. An electromagnetic field, essentially a force field, generated at the hilt contains the plasma in a defined beam and directs it back into the hilt. The crystal absorbs the energy and recycles it. Hence lightsabers are extremely energy-efficient, allowing Jedi Knights to use them for their whole lifetimes.
Fig. 2. Robert W. Schönholz, Blue Lightsaber, c.2016.
Of course, the lightsaber breaks the laws of physics. Electromagnetic fields do not work as they do on fictional planets like Coruscant. Energy-dense power sources such as Kyber crystals do not exist in real life, which leads us to the protosaber. In Star Wars lore, a protosaber is a lightsaber with an external power source. It was the predecessor to the lightsaber when Kyber crystals could not be contained inside the hilt. Since real-life high energy sources cannot be squished into the hilt, Hacksmith Industries' lightsaber build is reminiscent of the early protosaber.
The build
The engineers at Hacksmith Industries settled on liquefied petroleum gas (LPG) as the power source, the same gas used for home heating systems and barbecues. This gas is fed through the brass and copper hilt, and is burnt continuously to keep producing plasma. To form the beam shape of the blade, they incorporated laminar flow of gas. Ever seen videos of “frozen” water coming out of taps like this? Laminar flow occurs when layers of fluid molecules, in this case LPG, flow without mixing. In this instance, a smooth beam is created. Unlike actual lightsabers, the beam does not return to the hilt to be absorbed.
Of course, to be a lightsaber, it has to function like one, too. The plasma is extremely hot, reaching up to 2,200 degrees celsius. Therefore, it can cut through metal and other objects much like we see in the movies. This also means contact with the blade can lead to serious or even fatal injuries. The external power supply is in the form of a backpack, with mounted LPG canisters and electronics for assistance. Overall, the build looks, feels and works like a real lightsaber, which makes it a pretty accurate replica. However, we do not have the Force or ancient Jedi wisdom, so there are some notable imperfections in the design.
Fig. 3. “Finished lightsaber build”, Hacksmith Industries, 4000° PLASMA PROTO-LIGHTSABER BUILD, 2020.
Colours
Lightsabers come in a variety of colours, each reflecting the wielder's moral values in Star Wars canon. Blue, for example, represents justice and protection. Green, blue and red are the most commonly seen in the movies, but lightsabers also come in purple, orange, yellow, white and black. If you did high school science, you may remember mixing bunsen burner flames with salts to produce colours. The same principle applies here; salts can be mixed in with plasma to colour the blade. For example, Strontium Chloride gives a red colour, so you can finally live out your Sith fantasies.
Fig. 4. “Lightsaber colours by mixing salts”, Hacksmith Industries, 4000° PLASMA PROTO-LIGHTSABER BUILD, 2020.
Improvements
The downside of using plasma is that we cannot fight with it. Blades would pass right through each other without clashing. To fix this, a metal rod that can withstand high temperatures, such as Tungsten, could form the blade with a beam of plasma around it. However, this means the lightsaber would not be retractable, which defeats the purpose. To keep the blade coloured, salts have to be continuously fed through the hilt. This can be done with another pressurised canister along with the LPG, although it requires extra space.
Despite the imperfections, the protosaber by Hacksmith Industries is the closest prototype to a real-life lightsaber. With constantly evolving technology, we will be able to build a more compact model that more closely resembles those in the movies. Makers all around the world are building cool movie gadgets like the lightsaber, so keep a lookout for your favourite ones. You never know what the nerds may bring!
REFERENCES
1. Amy Tikkanen, “Star Wars”, Britannica, published April 10, 2008, https://www.britannica.com/topic/Star-Wars-film-series.
2, 4, 7. Hacksmith Industries, “4000° PLASMA PROTO-LIGHTSABER BUILD (RETRACTABLE BLADE!)”, October 2020, YouTube video, 18:15, https://www.youtube.com/watch?v=xC6J4T_hUKg.
3. Joshua Sostrin, “Keeping it real with the Hacksmith”, YouTube Official Blog (blog), November 12, 2020, https://blog.youtube/creator-and-artist-stories/the-hacksmith-10-million-subscribers/.
5. Daniel Kolitz, “Are Lightsabers Theoretically Possible?”, Gizmodo, published August 10, 2021, https://www.gizmodo.com.au/2021/08/are-lightsabers-theoretically-possible/.
6. Richard Rogers, “Lightsaber Battery Analysis”, Arbin Instruments: News, published October 3, 2019, https://www.arbin.com/lightsaber-battery-analysis/.
8. Phil Edwards, “Star Wars lightsaber colors, explained”, Vox, published May 4, 2015, https://www.vox.com/2015/5/31/8689811/lightsaber-colors-star-wars.