Title: Breaking strain
First published: 1990
Description: From back cover of Avon paperback November 1987:

Her code name is Sparta.  Her beauty veils a mysterious past and abilities of superhuman dimension, the product of advanced biotechnology.

When the injured freighter Star Queen arrives at Venus Station with a lone survivor on board, Sparta must risk her life to investigate what really happened during its deadly voyage in space.

She must solve this mystery even as she unlocks another -- the truth behind her own identity...