From the publisher:
To the humans, Eos offered a whole new world to explore with all of its challenges, threats, and rewards. But that was just the beginning. The critically acclaimed and ENnie-nominated Dawning Star: Operation Quick Launch introduced the Dawning Star Campaign Setting. In Helios Rising, it explodes with the fury of a thousand suns. Dawning Star is the only full-scale science-fiction campaign setting built on d20 Modern and powered by d20 Future.
Helios Rising presents the rest of the Helios System in all its glory, from the prison-planet Hephaestus to the steamy jungles of C’thalk to the deserted Tentaari Gateway Station. Each planet is described in exacting detail with extensive new rules uniquely tailored to it.