"Sector 1" may also refer to Sector 1 / Biosphere.
Sector 1 (SRX) is a sector of the Biologic Space Laboratories research station in Metroid Fusion. It is here that Samus Aran fights the Fake Chozo Statue and Neo-Ridley, and explores it at the beginning of her mission and at the end. Most of the sector is rocky with a few plants, with one area filled with lava, all reminiscent of SR388 itself, as this sector is meant to imitate the planet. There is also a Tourian-like part of the sector where Neo-Ridley is fought. Adam reveals that the sector's main purpose is for the Metroid Breeding Program (creating an environment similar to the Metroids' homeworld that allowed them to molt naturally and reach the Omega level rapidly using an unknown formula).
- Alpha Metroid (Husk left by Omega Metroid)
- Atmospheric stabilizer
- Elephant Bird
- Gamma Metroid (Husk left by Omega Metroid)
- Gold Space Pirate
- X Parasite
- X Spawn
- Zeta Metroid (Husk left by Omega Metroid)
- The main theme of Sector 1 has been remixed twice. The first time is in an arranged medley of Fusion's themes in the Metroid Prime & Fusion Original Soundtracks. The second time was in Super Smash Bros. Brawl as a theme available on the Frigate Orpheon. The same theme was later used on the Pyrosphere stage in Super Smash Bros. for Wii U.
- This is the only area in the game that does not contain a Data Room.
- The presence of lava in the SR388-like environment of Sector 1 led to fan speculation for years that lava was in fact the "dangerous liquid" found on SR388 in Metroid II: Return of Samus. However, this was ultimately disproven in Metroid: Samus Returns, a reimagining of Return of Samus, which confirms that the liquid is a purple substance of synthetic origin.
- This sector, despite being a replication of SR388, contained very few bioforms native to SR388. This can be explained by the near (if not total) destruction of the planet's ecosystem by the X Parasites and possibly Metroids (given the latter's dangerous nature), making Galactic Federation scientists' task of collecting varied specimens from SR388 a difficult one.
- Part of this sector leading up to Neo-Ridley is very similar to Tourian, suggesting that like Sector Zero on the BOTTLE SHIP, the Tourian-like area was likely created to assist with Metroid propagation. Sector 1 was not known to have a Mother Brain replica to control the new specimens, however.
"This sector reproduces the environment of planet SR388."
SECTOR 1 MAP
"Sector 1 was designed to recreate the environment on planet SR388, the native habitat of the X Parasite. Since the explosion, however, Parasites have contaminated the Sector's atmospheric stabilisers. One of Samus's first missions is to bring the stabilisers back online."
SECTOR 1 (SRX)
"The atmospheric stabilisers in Sector 1 have been taken over by X Parasites. As a result, the ecosystem is thick with fumes."