Arrival — Charles G. Dyer

This is the prequel to the popular Octant series.
A gigantic asteroid is on a collision course with Earth. The expected result could be the extinction of all life on Earth. Governments and scientists do not want the public to know about it for fear of widespread panic.
A wealthy international consortium builds a fleet of spacecraft using new untested technology and crewed by androids. Their most precious cargo is all the genetic material needed to re-create life as we know it, especially humans.
Exciting events lead to the human colonisation of alien worlds that becomes known as the Octant. Not everything goes according to plan. The androids never arrive at their intended destination owing to a mysterious space-time anomaly. The androids have to deal with a human stowaway.