Senior mission officer is a personnel designation assigned by Starfleet giving complete authority over a mission and its away teams to a specific individual.

In 2364, Starfleet appointed Admiral Mark Jameson as the senior mission officer for the USS Enterprise-D's mission to Mordan IV, as he had negotiated for the release of 63 passengers that Karnas had taken hostage in 2319 and was familiar with tunnels underground on Mordan IV. (TNG: "Too Short a Season")