BIOGRAPHY - Page 5
She moved to New York, where she ended up sharing an apartment with Misty Knight, a private investigator. Still, she kept in touch with the X-Men and she became a very good friend of Storm, while helping her to adjust to civilized life in New York. For example, Storm had no idea why there 
was any need for clothing if one didn’t feel cold, as she had lived for her entire adult life in the wild savannah of Kenya, far from populated areas. It was during one of their shopping tours that Jean learned of Storm’s severe claustrophobia when the two women were chasing a thief into a subway station. Naturally, Jean offered her support. [Classic X-Men #2]
While out on a date with Scott, Jean was captured by a new version of the mutant-hunting Sentinels and taken to their orbital station. The X-Men had no means to get there on their own, but Dr. Corbeau, a friend 
of Professor Xavier, was in charge of the United Nations' Starcore project. He quickly organized a space shuttle and piloted the mutants to the Sentinel inhabited base in Earth’s orbit. While they managed to free Jean and several other X-Men that had been abducted, the flight back turned out to be problematic. Reaching Earth would require them to pass through cosmic radiation and solar flare activity, but the shuttle's shielding was damaged. Jean reasoned that she alone stood a chance to survive by trying to filter out the radiation with a telekinetic shield; therefore she telepathically absorbed Corbeau’s knowledge to fly the ship and ordered everyone else into the life-cell, a specially shielded chamber in the rear area of the craft. However, the strain of piloting the shuttle and keeping her telekinetic powers up at full force was too strenuous, and ten minutes into the flight radiation began to pass through. [X-Men (1st series) #98-100]
As her body was already beginning to decompose, she was approached by the Phoenix Force. At first, Jean thought she was hallucinating but, after the Force assumed the shape of a humanoid entity to make it easier for Jean to communicate with her, it explained that it heard Jean cry out for aid. The Force made Jean understand that she was barely hanging onto life by force of will alone, her mind apparently refusing to acknowledge the full extent of her injuries for its own protection. It also tried to explain its nature to Jean, before offering to help her. That help came with a price, though, as the Force wanted to experience life in her place in order to explore humanity. Left with no other choice to ensure the save return of the other X-Men, Jean accepted. As they touched, the Force duplicated Jean’s body, infused it with some of her essence and life-force and merged with it. Instantly, the Force was overwhelmed and intoxicated with the rich experiences of life, friendship and love.
Unprepared to properly deal with the human emotions it had wanted to study, the Force denied its own consciousness and forced itself into believing it was the real Jean Grey, rather than just a copy. As such, "Jean" assumed she had undergone a literal rebirth, and she chose “Phoenix” as her new name.
Looking at the original Jean‘s near-dead body in front of her, the copy became confused, however. While Phoenix believed she was the real Jean Grey, she also detected the life that still existed within Jean's withering body. Not quite sure what to make of that, Phoenix decided to place the body in a healing cocoon, so that the physical damages could be repaired. In doing so, 
Phoenix unwittingly fulfilled the agreement it had made with Jean, but had alread forgotten after assuming her form. From this point on, the Phoenix Force fully suppressed any memory of the original Jean, outwardly and inwardly presenting itself as Phoenix, the one and only Jean Grey. [Classic X-Men #8, Excalibur (1st series) #52]
The shuttle crashed down in Jamaica Bay, and all of the passengers in the back made it safely out. However, the X-Men were in for a surprise when Phoenix dramatically rose out of the wreckage before passing out. Even though she was wearing a different costume and, by all rights, shouldn’t have been able to survive, the X-Men had no reason to believe that she wasn’t the real (and only) Jean Grey. While the cocoon containing Jean’s body sank to the bottom of the bay, the X-Men rushed Phoenix to a hospital, only to be given a clean bill of health. [X-Men (1st series) #101]
After being released from hospital, Phoenix continued living Jean’s life, so she returned to the apartment she shared with Misty Knight. Shortly afterwards, she invited her parents and Professor Xavier for lunch, but the happy meeting ended up being interrupted by Firelord, a former herald of Galactus. To protect those she loved, Jean had no choice but to reveal herself as a 
mutant in front of her parents. During the battle with Firelord, Jean was as surprised as he that she managed to stand her ground against a cosmically powered herald. Obviously, she displayed a much higher power level compared to her days as “plain“ Marvel Girl. For all her power, though, she realized too late that Firelord merely provided a distraction for another villain kidnapping Lilandra, an alien Shi’ar princess, whom Xavier had just befriended. Fortunately, Phoenix was able to re-activate the stargate that the Shi’ar agent had used, so that the X-Men could follow him.
In the far outskirts of the Shi’ar galaxy, the X-Men rescued Lilandra, only to learn of a much bigger threat. In a mad quest for power, Lilandra’s brother, Shi’ar emperor D’Ken, had tampered with and eventually damaged the structure of the M’Kraan crystal, a nexus to all realities. Entering that crystal, the X-Men found themselves in a beautiful but also unsettling alien city, with a glowing energy sphere in its center. That energy sphere contained neutron galaxy that, if the lattice remained damaged, would draw in all of the universes mass into a big bang, to create a new universe.
Phoenix realized that she could use her vast energies to heal the sphere, but feared that she would be fully absorbed by it. To anchor herself to humanity she linked with the lifeforces of Storm and Corsair of the Starjammers right before she flying into the sphere and engulfing it by a bird shaped-energy signature. This Phoenix effect kept growing and growing, even dwarfing the whole solar system, until finally the impossible task was accomplished. During the process, Phoenix touched the life-forces of the whole universe. [X-Men (1st series) #105, 107-108]