Yuria is one of the ship's youngest crew members (17 years old). She fills in for Yuki at radar when Yuki is off shift (one of at least two women that do so). She was seen in episode 2 when the crew is being taken to Yamato. She's the girl listening to an MP3 like player while the young guy next to her is checking her out (he's the young security guard). We see her next in episode 4 as she takes advise from Yuki. We see her again in episode 6 helping out the nurse with first aid.
She starts running the ship's onboard radio station in episode 7 and does that for most of Chapter 3 along with some contact with whatever is in the autopilot room which seems to be a major plot point for Chapters 4 and 5.