Black box
From Memory Alpha, the free Star Trek reference.
A black box is colloquial term for a device aboard aircraft or starships which are designed to withstand extreme stresses of impact or concussion forces to preserve flight recorder data such as speed, heading, XYZ orientation, alert status and/or crew logs within to assist investigators in determining what events led to the incident.
When the Enterprise came upon an unknown small craft in 2152, Trip Tucker and Malcolm Reed attempted to locate various objects in it, including a black box, which they could not locate. (ENT: "Future Tense")
