NASA engineer David Burns has proposed a theoretical engine concept capable of reaching near the speed of light without using propellant. The concept, named the Helical Engine, utilizes principles from special relativity and high-tech particle accelerators, like those at the Large Hadron Collider. By accelerating ions in a loop and manipulating their velocity, the engine could theoretically achieve speed of light of around 297 million meters per second. Despite its potential, practical challenges exist, including its large size and minimal thrust production. If successful, this technology could significantly impact space travel.