The drive unit is a Galactic Federation technology used as an engine for starships.
In a Metroid: Other M cutscene revealing the incident that led Samus Aran to defect from Adam Malkovich's command, the civilian spaceship Lusitania is seen being towed by the Federation Army Special Ops Battleship VIXIV, with the drive unit attached to the former ship. Ian Malkovich was repairing it before it went critical. Adam ordered the drive unit to be detached, but the VIXIV's operators were reluctant, as was Samus, who insisted to save Ian. As she puts it, "if [they] had waited any longer, it would have meant the end of those [they'd] come to rescue, and the end of [them] as well." The drive unit was detached, and it was last seen exploding over a planet, killing Ian.