Venturer Twelve Series by Dan Morgan, John Kippax

In the dark of space lies a new dimension of fear...The stars are no longer neutral and Mankind becomes aware that the skies are shared with an alien race.United Earth and its colonies are protected by thinly spread starships or the space corps manned by such very qualified men and women as Tom Bruce of Venturer Twelve and Helen Lindstrom, his second-in-command.In Space they had to play God.And the worlds hated them for it.

The thinly-spread starships of the Space Corps were all the protection Earth's galactic colonies had. Yet the colonies fought, lied and cheated, to win independence of even this slender thread of control.Kepler III was one such colony. It was approaching its centenary... moreThe thinly-spread starships of the Space Corps were all the protection Earth's galactic colonies had. Yet the colonies fought, lied and cheated, to win independence of even this slender thread of control.Kepler III was one such colony. It was approaching its centenary. On the way was Venturer Twelve, Commander Tom Bruce, sent out to investigate and establish whether or not the colony was progressing sufficiently well to be freed and declared independent of the commercial company which had founded and financed it. And on Kepler, President Shanon Kido was dtermined the investigation would turn up nothing - absolutely nothing - to endanger that independence.Even if it meant endangering the planet... less

United Earth Government couldn't get the vast appropriations needed to commandeer an entire planet - necessary to experiment with the titanic forces that would be unleashed while doing research on a warp-drive.And meanwhile, Venturer Twelve and her sister ships continued to protect Earth Sector as best they could, knowing the aliens must already have the drive.But their worst enemy was right there on Earth.

The fourth book of Venturer Twelve