Ship was an AI designed by Eve's people and placed on the escape craft with Eve when she was still small with instructions to protect the girl and teach her to control her powers properly.
During a great war (Most likely the Last Great Time War) Eve's people and planet were 'exterminated' (a reference to the Daleks) due to their ability to read and (possibly) manipulate the timelines. Eve's parents designed and built Ship and sent it far across the stars with Eve on board and instructions to protect her and teach her to use and control her powers when she is old enough.
The pair traveled for a long time before an unkown event caused Ship to crash land on Earth, burying itself under a ton of sand and causing massive damage to its systems. The damage left Ship severly weakened so she was unable to care for Eve until her systems rebooted which would take approximately 20 earth years. This became a problem because the immense power Eve possessed meant that until she was old enough and instructed properly on how to control her powers she would be a danger to herself and anyone around her. Fortunately Eve was discovered by the caretaker of the local fun fair Harry who, after being informed of the situation by Ship, happily helped raise Eve in the confines of the Fun Fair where she would be safe and able to practice controlling her powers by manipulating the fairground rides at night.
Unfortunatly has the years went on Eve (Who while looking like an adult was still technically a child by her species's standards) became increasingly lonely and began to control homeless people who wandered in to the park at night because she wanted friends. Rani evetually investigated and discovered Eve living in the abandoned mine ride. After talking with Eve and realising she no threat but rather a form of alien refugee Rani decied to take Eve outside as she believed it was unfair for her to be locked up like this. Ship (who by this time was strong enough to project her image on to a reflective surface) tried to frighten Rani and Sarah Jane (who had recently arrived at the Fairground) by showing Rani her future and reading Sarah Jane's mind. This failed and a determined Rani took Eve outside despite Sarah Jane warning her that she didn't know the full story.
This proved to be a mistake as Eve (who had never been outside before) was overwhelmed by all the new sensations she was experiencing for the first time and began to use her abilities at a stonger level than she had before; even putting Rani under her control when she declared that because of what Eve was doing they weren't friends any more. Beliving the face in the mirror (Ship) knew what was going on, Sarah Jane and Clyde returned to the staff room where Sarah Jane talked with Ship, asking what was going on. Realising that Eve was outside, Ship told the pair that Eve must be returned inside as her powers were too great for her to control at her current age, and if she continued to do so they would destroy her.
Ship's words proved true, as Eve's powers began to harm her body with jolts of excess energy. Only Ship had the power to stop her so Sam, Clyde and Sarah Jane took her back to to the beach were Ship liberated itself from its hiding place deep beneath the sand. Glad to see Eve after so long Ship instructed her to place her hands on the core were she drained off Eve's excess energy thereby saving her life.