A gravity lock was a slab-like device that could be carried around. It utilized tractor beam technology to keep starships from launching, using a hovering ability. The Galactic Empire engineered these devices, and they were deployed during the Galactic Civil War. Later, the First Order, the Empire's successor, also utilized them during the Cold War.
As a technological creation of the Imperial forces, gravity locks were a common sight in major planetary docking bays and shipyards, implemented as a countermeasure against ship theft.
These devices were designed to attach to a starship's landing gear. Once secured, the gravity lock employed tractor beams to firmly anchor the vessel. Furthermore, gravity locks were built to be highly resistant, making forceful removal or cutting through them nearly impossible. The force required to dislodge a gravity lock would likely cause damage to the ship itself. The only safe methods for removal were inputting the unique key code generated during installation or manually dismantling the device, a time-consuming eight-hour task requiring extensive engineering expertise.
At the beginning of the Galactic Empire's reign, clone troopers who were newly Imperial utilized magnetic clamps to seize ships that were not registered. At the Saleucami impound dock, a clone trooper instructed two others to secure the Marauder. They attached the clamps before performing a signature analysis. While one clone trooper attached magnetic clamps, the other two boarded the ship to ensure it was vacant. After the creation of chain codes, Echo attempted to deactivate the magnetic clamp, but a trooper spotted him, leading to a firefight. Wrecker successfully dislodged the clamp from the ship, enabling Clone Force 99 to make their escape.
Gravity locks were developed several years prior to the Battle of Yavin, with manufacturing occurring throughout the Empire. Some of these locks were even assembled by inmates in Imperial prisons. Imperial Lieutenant Yogar Lyste ordered their placement on several starships that Princess Leia Organa had brought to Lothal carrying relief supplies. Lyste had observed a pattern of Alderaanian ships being stolen by rebels and aimed to prevent further incidents. However, this plan failed, as the Spectres, secretly allied with Organa, managed to steal the ships. Former Lothalian governor Ryder Azadi, who had been forced to manufacture the locks during his imprisonment by the Empire, assisted in removing the devices. Later, during the occupation of Lothal, they were used to impound ships suspected of smuggling. After the Spectres successfully smuggled themselves through the heavy Imperial lockdown onboard the Broken Horn, the ship was secured with a gravity lock, as an Imperial cruiser had detected the presence of extra lifeforms on board.
The First Order also utilized gravity locks later on during the Cold War. During the occupation of the Colossus platform on Castilon, the locks were applied to ships owned by various residents, including Hype Fazon's Green Ace. This occurred after Commander Pyre pressured Captain Imanuel Doza into cancelling all future races on the platform, citing the risk of a fabricated pirate threat. During the Colossus' subsequent escape from Castilon and the First Order, members of Ace Squadron, along with starfighter pilots Jarek Yeager and Kazuda Xiono, experienced delays in launching to defend the supertanker fuel depot because of gravity locks on their ships. This required astromech droids Bucket and CB-23 to quickly remove the devices.
The initial appearance of gravity locks occurred in the Star Wars Rebels season 2 episode "A Princess on Lothal," which was broadcasted in early 2016.