From Halopedia, the Halo wiki
The Jupiter-1 is a type of starship maneuvering engine created by Orphios Energy Systems.
Jupiter-1s were on the destroyer UNSC Calcutta. Six of these were later installed on the UNSC Spirit of Fire after the destroyer was scuttled.
A cut away of three of the Spirit's Jupiter-1s.
The Spirit with unengaged Jupiter-1s in Halo Wars 2.
All six Jupiter-1s as seen in Halo: Escalation.
The Jupiter-1s as seen on a replica model of the Spirit of Fire.