One of the primary jobs of the FederationStarfleet. One of the dullest jobs un the services, paroling a given sector of space to rescue people. Weeks of tedium punctuated by moments of sheer terror.
The ships chosen for SAR are called "cutters" regardless of size. Some cutters fall into the heavy range. The preferred ship is fast and roomy. Often the cutter has to take on large numbers of unexpected passengers. Purpose built ships are usually in the 400 to 500 meter range with lots of room and small crews.
Some people see this as the glamor job. Andorians consider it the second best job. Tellerites consider then the handmaiden of the merchant fleet. A dull but a proud and vital duty.