Darkship Renegades by Sarah A. Hoyt (Book, 2013)
Book 2 in the rollicking and award-winning space adventure, the Darkship series! After rescuing her star pilot husband and discovering the dark secret of her own past on Earth, Athena Hera Sinistra returns to space habitat Eden to start life anew. Not happening. Thena and Kit are placed under arrest for the crime of coming back – alive! The only escape from a death sentence: return to Earth and bring back the lost secret to creating the Powertrees, the energy source of both Eden and Earth whose technological secrets have been lost to war.