Where is the Missile Expansion in Vault (Metroid Prime Origins)?

The Missile Expansion is in Vault, Chozo Ruins. To get there you need Missile Expansion, Morph Ball first (starting a new game).

What you need first

Starting a new game from Landing Site, get these first, in this order, then go to Vault (22 rooms in all):

1. Missile Expansion in Landing Site (0 rooms; needed for Missile Expansion (Missile))
2. Morph Ball in Ruined Shrine (9 rooms; needed for Missile Expansion (Morph Ball))

Last stretch

From Ruined Shrine, door by door:

1. Ruined Shrine: go through the door to Ruined Shrine Access → Ruined Shrine Access
2. Ruined Shrine Access: go through the door to Main Plaza → Main Plaza (Missile Blast Shield; needs Missile)
3. Main Plaza: go through the door to Nursery Access → Nursery Access
4. Nursery Access: go through the door to Eyon Tunnel → Eyon Tunnel
5. Eyon Tunnel: go through the door to Ruined Nursery → Ruined Nursery
6. Ruined Nursery: go through the door to North Atrium → North Atrium
7. North Atrium: go through the door to Ruined Gallery → Ruined Gallery
8. Ruined Gallery: go through the door to Totem Access → Totem Access
9. Totem Access: go through the door to Hive Totem → Hive Totem
10. Hive Totem: go through the door to Transport Access North → Transport Access North (Missile Blast Shield; needs Missile)
11. Transport Access North: go through the door to Transport to Magmoor Caverns North → Transport to Magmoor Caverns North
12. Transport to Magmoor Caverns North: go through the door to Vault Access → Vault Access
13. Vault Access: go through the door to Vault → Vault

More Missile Expansions

• Missile Expansion (Burn Dome)
• Missile Expansion (Crossway)
• Missile Expansion (Dynamo)
• Missile Expansion (Dynamo)
• Missile Expansion (Furnace)
• Missile Expansion (Gathering Hall)
• Missile Expansion (Hive Totem)
• Missile Expansion (Main Plaza)
• Missile Expansion (Main Plaza)
• Missile Expansion (Main Plaza)
• Missile Expansion (Ruined Fountain)
• Missile Expansion (Ruined Gallery)
• Missile Expansion (Ruined Gallery)
• Missile Expansion (Ruined Nursery)
• Missile Expansion (Ruined Shrine)
• Missile Expansion (Ruined Shrine)
• Missile Expansion (Training Chamber Access)
• Missile Expansion (Watery Hall)
• Missile Expansion (Watery Hall Access)
• Missile Expansion (Fiery Shores)
• Missile Expansion (Storage Cavern)
• Missile Expansion (Triclops Pit)
• Missile Expansion (Elite Control Access)
• Missile Expansion (Elite Research)
• Missile Expansion (Fungal Hall Access)
• Missile Expansion (Fungal Hall B)
• Missile Expansion (Main Quarry)
• Missile Expansion (Metroid Quarantine A)
• Missile Expansion (Metroid Quarantine B)
• Missile Expansion (Phazon Processing Center)
• Missile Expansion (Security Access A)
• Missile Expansion (Frost Cave)
• Missile Expansion (Gravity Chamber)
• Missile Expansion (Ice Ruins East)
• Missile Expansion (Ice Ruins East)
• Missile Expansion (Phendrana Shorelines)
• Missile Expansion (Phendrana Shorelines)
• Missile Expansion (Quarantine Monitor)
• Missile Expansion (Research Lab Aether)
• Missile Expansion (Research Lab Hydra)