Driving Bergmann's Comet — George G. Pinneo

Driving Bergmann's Comet builds on the two previous books in the series, detailing how Bergmann's human team comes together to assist Banderat space grunts in diverting the last comet threatening Earth with a world-wide 'winter-in-summer'.  One comet is steered to impact Mars, helping terraform the Red Planet for a future expedition.  Following the sucessful comet diversion, Bergmann's Team plans the constuction of a permanent orbitat at L5, which will allow easy access to the Lunar surface and a jump-off point for Mars.