Merchant Marine

The Merchant Marines or Merchant Service was a group within the Federation that operated various survey vessels and freighters.

The SS Beagle, commanded by Captain R.M. Merik, was a vessel operated by the Merchant Service. Merik joined the Service after dropping out of Starfleet Academy during his fifth year. 

Carstairs, of the USS Enterprise (NCC-1701), formerly served on a Merchant Marine freighter in the Canopus region. His ship had at one time visited Alpha Carinae II to conduct a geology survey of the planet for a mining company.