YSS Gosei , YX-C1-0009, is a Tansaku-class Science Vessel built at the Ketsurui Fleet Yards on Yamatai (Planet) in YE 31 for the Scientific Studies Service (SSS). It was upgraded to the 1B version in YE 33

The Gosei was dispatched to explore the Saiki Nebula. While the ship was stationary and deploying drones, it encountered a gravitational anomaly. Even though damaged, the Gosei was able to complete its initial survey and returned back to Daichi.

• SX-06 - YE 32
• SX-07 - YE 33
• UX-5 - YE 35