During her journey, there will be a number of hidden areas and rooms that currently be accessed that Samus can find Missile Expansions. Missile Expansions, as the name might hint, allow Samus to upgrade and increase the amount of Missiles she can carry at any given time, as her Missile Launcher is not equipped with unlimited ammunition. There are even a few Super Missile Expansions found in the game, ones that will raise the max capacity of Samus' power suit much greater than the normal missile expansion.