In the Star Trek Enterprise episode ‘Silent Enemy’, the Enterprise NX-01 is attacked by an unknown alien starship, as Archer orders the crew to install experimental “phase cannons”


While deploying subspace amplifiers to improve their ability to communicate with Starfleet, Enterprise is approached by an alien vessel. Captain Archer hails them, but the vessel returns to warp. He wonders why: Ensign Sato points out that the Universal Translator is far from perfect, and Sub-Commander T’Pol says that some species have motives that cannot be understood in human terms. Soon, however, the mysterious ship returns and scans the Earth ship, sending a high pitched screech through the com systems, and firing on Enterprise before again jumping to warp.

The Enterprise simply isn’t prepared to deal with such hostile space threats, the ship is equipped with experimental phase cannon ports, but the weapons weren’t properly installed because of their early departure from Earth. To prepare for the next round, the crew hastily need to install new weapon technology and to conduct tests of the phase cannons. Asked to “shave a few off the top” of an alien moon, the test fails due to an overload which causes the weapons to blow up the mountain and create a new crater on the satellite. It turns out that the overload was caused by an alien device.

“A phase cannon was a phase-modulated directed energy cannon weapon, a type of particle weapon which served as a successor to plasma cannons and as a precursor to the phaser of the 23rd and 24th centuries. The prototypes of ship-mounted phase cannons were first introduced by Starfleet in the mid-22nd century, designed as the primary defense of NX-class starships and serving as a supplement for the lacking spatial torpedoes of the time. The first NX-class vessel to test and actively use phase cannons in battle was Enterprise NX-01.”

“Designed as a starship-based version of the hand-held phase-pistol, the phase cannon was rated for a maximum power output of 500 gigajoules. The cannons of NX-class starships were mounted on retractable turrets which extended from the ship’s hull when deployed and rotated as they were being targeted. Like phase-pistols, phase cannons emitted a concentrated beam of energy that could be set at different yields. ”

Memory Alpha