From Halopedia, the Halo wiki
Galileo's Worst Enemy was a small tug owned by Oliver Birch. He used the ship in conjunction with CAA Butterworth to prospect and retrieve derelict Shaw-Fujikawa Translight Engines on fetching runs.
The ship was named after Father Orazio Grassi, a Jesuit priest, astronomer and a mathematician who opposed Galileo Galilei's theory on the nature of comets. Remarkably, Grassi criticized Galileo's theory for scientific, rather than religious, reasons.
List of appearances