Probe 2 is the callsign for Lieutenant Starbuck's Viper during the discovery of the magnetic void.
After losing contact with Probe 1, piloted by Captain Apollo, Starbuck enters the void after Apollo at full turbo, firing his lasers. Upon finding Apollo, Starbuck performs a "perfect 180-degree" turn, which leads both fighters out of the dangerous void (Lost Planet of the Gods, Part I)