Piston

A piston is a component of various pumping or engine systems in the Metroid Prime series. They are commonly found in the areas explored by Samus Aran as obstacles, involved in puzzles, or are simply part of the room.

There are three rooms in the series containing the word "piston" in their name: Piston Tunnel (Chozo Ruins), Piston Cave (Alinos) and Piston Hall (Eastern SkyTown, Elysia). Pistons play a role in the former two rooms, while a rotary hatch exists in the latter.

Redirect Generator piston, Generator piston system, Piston structure, get images of all mentioned pistons

Traversal
Certain Morph Ball tunnels, such as the Piston Tunnel and Piston Cave, feature slowly rising and falling pistons that Samus can roll on top and use as a makeshift elevator. Some pistons are positioned above Samus and will cause damage if one slams down while she is under it, (Metroid Prime) or kill her. (Metroid Prime Hunters) The pistons in the Piston Cave make traversing the room particularly difficult as they can easily knock her to her death in lava, or crush her.

Reactivating the G.F.S. Theseus enables a rising and falling piston in the tunnels leading into the ship. Samus must time her Bomb-Trick or Spring Ball and Bomb correctly while the piston is retracted. This allows her to access the Theseus roof and find a Missile Expansion.

Obstacles
Generator A, C and presumably B in Base Sector Zero use a piston system, which are offline when Samus enters the rooms. After she uses a security lever at the back of the room, the pistons will stall, and she must engage their override by using a Hand Scanner. However, the wall pistons will still be stuck, forcing her to manually dislodge them by using a Bomb Slot in the walls.

In the Auxiliary Dynamo room of Bryyo Thorn Jungle, the exit is blocked by indestructible and non-removable wires. To bypass them, Samus must navigate a Morph Ball tunnel in the wall, but there is a piston blocking her path. She can remove it in bipedal form using the Grapple Lasso.

The Main Cavern features pistons in the floor, which extend upward when the Mining cannon is firing its Phazon-cutting lasers.

Scenery
Immersion pistons are found in the Monitor Station of the Magmoor Caverns. These siphon lava from the room to use as geothermal power.

Piston structures exist in Hub Access and Transit Tube B in Eastern SkyTown, as well s Western SkyTown. They appear as tall cylindrical structures in the center of the room, with flashing lights moving up and down the shafts. These pistons produce energy that supplies power to the engines of the Sky pod.

Scans

 * Auxiliary Dynamo:"Piston is stuck in place. Enough physical stress could temporarily pull it down."
 * Generator piston system (Generator C):"Generator piston system active. Piston is in place and secure. Ready for generator activation."
 * Piston structures:"Piston structure produces energy that is used to supply power to the pod engines."
 * Main Cavern (Mining cannon):"Piston extends while the mining cannon is firing the beam that cuts through Phazon."