The SpaceHunk appears to be a debris chunk of the SJ Sathanas juggernaut. Though it does not appear to have any purpose, and did not appear in any FreeSpace missions, it was included in the FreeSpace retail tables. Its purpose remains a mystery.
FS2 Tech Room Description
It's a piece.
|Max Velocity||25.0 mps|
|Max Afterburner Velocity||N/A|