Acknowledgments

I am grateful to the following for assistance with research, suggestions, and comments:

•  Jardine Barrington-Cook and his colleagues of the Space Division, Logica U.K. Ltd., who developed the guidance software for the Huygens Titan landing probe.

•  Mitchell Clapp of Pioneer Rocketplanes, author of the Black Horse spaceplane proposal.

•  Martyn Fogg, author of Terraforming: Engineering Planetary Environments, the standard text on the subject.

•  Dr. J. F. Zarnecki of the Space Sciences Unit, Kent University, U.K., who developed the surface science package for the Huygens probe.

and to the following for reading versions of the manuscript:

•  Simon Bradshaw

•  Eric Brown

•  Kent Joosten of the Solar System Exploration Division, Johnson Space Center, NASA.