Eventually, she arrived on Earth, and chose to join in the Legion tryouts. She was accepted, alongside Magno and Umbra, and chose the codename Sensor (a homage to "Sensor Girl," Princess Projectra's later codename in the pre-Zero Hour Legion) because of her powers as a mentalist.
She served with the Legion for some time - even during their disbandment when half the team were "Lost", she was a key component of R.J. Brande's plan to construct the artificial planetoid Legion World, allowing them to hide the construction efforts while Brande and Cosmic Boy plotted to restart the team.
After most of the Lost members returned and the team formally reinstituted, she continued to serve with the team, until she was struck by a bolt of "Hypertaxis energy" while on Xanthu. This caused her to mutate out of control until the arch-villain Ra's al Ghul managed to stabilise her in a form rather different from her original body. Bitter after the change, she took to hiding in her quarters with the lights off, refusing to speak to anyone until she was forced out of hiding when the rest of the team (as well as everyone else on Legion World and several other planets) was enslaved by Universo, while she proved to have a natural immunity. After Shikari managed to free herself, the two were forced to use an unstable Threshold link to the planet Steeple to escape their teammates. There, they met with Ferro and Karate Kid, and the monks who resided there created crystalline necklaces which allowed her to extend her immunity to mental takeover to them. While the other three were enslaved by Universo quickly, she managed to fool him long enough to free Saturn Girl and Dreamer. With aid from Apparition and Ultra Boy's child, Cub, Saturn Girl proved able to defeat Universo, and Sensor co-nominated Dreamer for Legion membership. She is now slowly adjusting to her change of form.
In the new Legion continuity launched in 2005, Sensor has disappeared and in her place is a new version of the original, humanoid Princess Projectra (possessing her enhanced abilities as Sensor Girl).