The R-352 was developed sometime before the Intercorporate War. It was planned to be used against General Resource's Orbital Satellite Laser after its discovery by the R-808 Phoca. Depending on the choices of Nemo, he would either attempt to destroy the R-352 as it launched from Comona Islands, or pilot the craft itself and engage the satellites in outer space.
- "A shuttle developed for anti-satellite duties in outer space operations. It is generally classified as a stratosphere insertion rocket. It has many devices to allow for the rapid control of the aircraft in space, where it is not affected by gravity. Much of the interior is dedicated to propellant used for maneuvering in space, and it boasts outstanding mobility for a spacecraft."
- ― Ace Combat 3: Electrosphere - Namco Official Guide Book
How to Unlock
- The R-352 Sepia is only available during the mission Zero Gravity in both the Japanese and Export versions of the game.
- Power: 20
- Mobility: 100
- Stability: 50
- Armor: 100
- Attack: 30
- Width: 10.74 m
- Length: 30.16 m
- Height: 4.90 m
- Weight: 60,280 kg
- Max Speed: 3,981 km/h
- Damage Tolerance: Heavy
- Originally, the Sepia was named R-302 during development. This was shared with the unrelated YR-302 Fregata.
- As is the case with the other aircraft of the R-series, the Sepia is named after the genus of the Cuttlefish.