Atlas's powers and abilities
As Power Man, Josten had phenomenal superhuman strength and resistance to injury due to his body being suffused with radiation from "ionic rays". As Goliath, Josten's invulnerability and strength returned to their normal levels, and he could also increase his size to upwards to 50 feet due to a formula based on the size-changing Pym Particles.
The ionic and Pym Particle formulas played havoc with his body's physiology and his mental state, until his body was purged of Pym particles. As Atlas, Josten maintains his former levels of strength, invulnerability, and size-changing ability due to his ionic treatments. Similar to the hero Wonder Man, Josten became "fully metamorphosed" into "unspecified superhuman flesh-like substance nourished by ionic energy" (Official Handbook Deluxe Edition). Eventually his body overextended itself, and Josten's body seemed to explode. He briefly existed solely as ionic energy, which he could infuse into the body of Dallas Riordan. In so doing, Riordan would becomes endowed with the strength, invulnerability, and size-changing powers of Josten. During an escape from Counter-Earth, Josten again overextended his body's ionic energy, seemingly burning himself out and creating a new body for himself separate from Riordan.
After Counter-Earth, Josten returned to using an infusion of Pym particles to fuel his size-changing powers.
Josten has become a being of pure ionic energy similar to Wonder Man after reforming himself from the effects of an ionic bomb made by Count Nefaria. His ionic energy makes him virtually immortal as well as no longer requiring food, air, water, or sleep. His perceptions and reflexes are also well above those of a normal human's.
Possesses great strength even in his normal form. As he grows in size, his strength and durability increase.
Atlas' limit, when he used Pym Particles, was a height of 60 feet. However, since his ionic form allows him to grow without Pym Particles, he may be able to reach greater limits.