The Star Trek fictional universe contains a variety of weapons, ranging from missiles (the classic photon torpedo) to melee (primarily used by the Klingons, a race of aliens in the Star Trek universe). The Star Trek franchise consists primarily of several multi-season television shows and a dozen movies, as well as various video games and inspired merchandise. Many aspects of the fictional universe impact modern popular culture, especially the lingo and the idea of a spacecraft launching space torpedoes and firing lasers, and have had a wide influence in the late 20th to early 21st century. Star Trek is popular enough that its science fiction concepts have even been studied by real scientists, and NASA described its science in relation to the real world as "entertaining combination of real science, imaginary science gathered from lots of earlier stories, and stuff the writers make up week-by-week to give each new episode novelty." For example, NASA noted that the Star Trek "phasers" were a fictional extrapolation of real-life lasers, and compared them to real-life microwave based weapons that have a stunning effect. Energy weapons The franchise depicts various weapons which fit the motif of the raygun, the most prominent of these being the "phaser". These directed-energy weapons emit energy rather than a projectile. A hand phaser can be set to "stun" or "kill". Phaser Phasers are common and versatile phased array pulsed energy projectile weapons, first seen in the original Star Trek series and later in almost all subsequent films and television spin-offs. Phasers range in size from small arms to starship-mounted weaponry. Though they seem to discharge in a continuous "beam", close observation reveals that phasers actually discharge a stream of pulsed energy projectiles into the target. Phaser output can be adjusted in both area of effect and output: a typical hand phaser can be adjusted so that it will merely shock or stun a living organism, while the effects of higher settings range from burning, and disintegration to true vaporization. This versatility means they can also be used as welding torches or cutting tools, and can create heat sources by firing at a large, solid object (like a rock). The stream can be adjusted to strike multiple targets at once, strike a single target with precision, or even destroy large amounts of material. Phasers can be set to overload, whereby they build up a force-chamber explosion by continuously generating energy