Joe Haldeman 
Worlds Apart [EPUB ebook] 
Worlds Book 2

Earth was finished, devastated by nuclear and biological war. The inhabitants of the artificial asteroid colonies looked down on it and knew that humanity’s old home would soon be gone forever.But Earth would not loose its ties so easily. And for Marianne O’Hara there was work that had to be done among the stricken ruins before she could at last look outwards to the stars.