Cant remember book title?

I read this book some 30years ago, think it was called something like freedom at zero point , or just zero point .
the hero was the last to survive a war with earth, his ship was symbiotic and called a whisper ship and would die when he did ,he did find a army of his own kind that had been kept as some form of crystal but they where wiped out, after his death his mind was kept in the mind of a female along with others .
the cover of the book showed the hero in the cockpit of the whisper ship with a oxygen mask on the background was all yellow I think hope someone can help.