A first in the series, the player takes full control of the spacecraft. The ship is one of five assigned to scout new frontiers under the First Expeditionary Batch and authorized by the USTA. The Calnus contains a flight deck where the player can pilot the ship to various planets throughout the game. Further inside is the spacious recreation room where the player's teammates hang out and the conference room, where the player can gather the crew to come up with new ideas for Item Creation. The crew's quarters are where all the crew sleep and rest during space travel. A battle arena is also available for the player and his teammates to practice combat. The ship is one of the sources of Private Actions that can occur in the game.
At 85.6 meters in length, this vessel was powered by an antimatter which feeds a fusion pulse engine in addition to boosters and a warp drive. This vessel excelled in both intra- and extra-atmospheric conditions and arrived at USTA's Moonbase in A.D. 2095.
The SRF-003 Calnus is upgraded twice throughout Star Ocean: The Last Hope.
The Calnus-II is an upgraded version of the Calnus, extensively repaired and refurbished under the watchful eyes of the Eldarians after the crash-landing on Aeos. The ship's warp engine power output and reliability have been considerably improved, and it now boasts a stabilizer, making it far sturdier than its previous incarnation. The modifications made to the craft have helped it realize a 25% boost in warp speed. It's at this point in the story that Edge is officially made Captain of the Calnus.
A further upgraded version of the Calnus that has been armed and modified for assault warfare on En II, making it more powerful and mobile in battle against enemy Phantom craft. It has been equipped with two large particle cannons, and excess energy from its newly-upgraded generator can now be diverted to the ship's electromagnetic shield. These upgrades have made it impossible for the craft to perform atmospheric re-entry; in order to execute the job, the extra weaponry must first be discarded entirely. The addition of highly mobile thrusters verniers give the ship astonishing speed in action.