A cargo ship is a Galactic Federation dropship configured to carry both GFMC personnel and cargo. Cargo ships are large in size and include four thrusters that double as supports for the ship when it lands. The cargo ship at the end of M15: Mother Lode is also equipped with a missile launcher, which it uses to destroy the Federation mining outpost. It is not to be confused with a Galactic Federation dropship, which has only three thrusters and is used exclusively for transportation of soldiers.
The cargo ship appears in five missions of Metroid Prime: Federation Force. All of these missions require the Federation Force to transport an important object or resource to the cargo ship to be brought to the G.F.S. Aegis. These missions are M02: Hardball, M09: Blender, M13: Phantom, M15: Mother Lode and M17: Infestation. When the Force is moving cargo, they will always come under attack by hazards, Space Pirates or other enemies who will try to kill the soldiers and/or destroy their cargo.
Upon reaching the ship, the soldiers can load their cargo onto a storage platform, where it will float in place (smaller cargo). In the case of larger carts carrying power cells or unknown material (M09 and M15), the cart will lock in place on a slot inside the ship. Once all cargo is loaded, the soldiers can use an Extractor, also inside the ship to end the mission. While most transportation-based missions require the collection of objects, the Metroid Eggs that the team is tasked with obtaining in M17 are optional for a bonus objective. However, collecting them is seen as a canon choice, as one egg that is collected is seen in the secret post-credits ending that only unlocks by completing the bonus objective.