The Corellian Corvette is a instanced dungeon, which means that only your group is up there. You can take a maximum of 8 people up there. There are 9 different missions onboard the Corvette, for Rebels, Neutrals, and Imperials, each of which may choose Assassinate, Rescue, or Destroy missions. Also in the Corvette you can find the Power Plant AV-21, which is required to make an AV-21 Landspeeder. You get the schematic for that vehicle by completing the mission.