The drive unit is a Galactic Federation technology used as an engine for starships.
In a Metroid: Other M cutscene revealing the incident that lead Samus Aran to defect from Adam Malkovich's command, an unnamed civilian spacecraft is seen being towed by another starship that is also unnamed but is likely the Federation Army Special Ops Battleship Vixin IV, 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 Vixin IV'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.