A log buoy downloads all pertinent data from a starship or starbase under threat and stores it for future analysis by investigators. This device can withstand the total destruction of a starship or starbase with minimal damage, or can be launched in a last-ditch effort before destruction or capture. (Star Trek II: The Wrath of Khan)
The log buoy can also be called a recorder-marker, recorder marker, mission recorder, data recorder, flight data recorder (sometimes known as FLIDAR) and flight recorder amongst other things.
The USS Enterprise had encounters with at least two recorder-markers within the first few months of their mission under Captain James Kirk's command. In 2265, the SS Valiant's recorder-marker from 2065 was brought aboard, surprisingly in working order. (TOS: "Where No Man Has Gone Before") Months later, in 2266, the Enterprise launched a recorder-marker when threatened by Fesarius, but it was destroyed. (TOS: "The Corbomite Maneuver")
In early 2295, during a shakedown cruise of USS Denpasar, officers from the starships USS Ajax, USS Jemison and USS Corregidor joined a Shadowstar expedition to determine the fate of the UNSS Jutland, whose flight data recorder was found 10,000 light years from its last reported position, 140 years previously. (Star Trek: Shadowstar Station: "Morituri te Salutamus")
A Special Operations team using the USS Koru as a base of operations were responsible for recovering the USS William Hamilton's flight recorder in 2372. The USS Cantabrian engineering team attempted to recover data from several Starfleet starships destroyed by the Myhr'an around the same time in the same year. During this time, chief engineer Ethan Arden called one flight recorder "a right little tart". (Star Trek: The Cantabrian Expeditions: "Catalyst, Part One", "Catalyst, Part Two")