They have been barnstorming it ever since. Mr. Zubrin compares NASA's approach to that of 19th-century Arctic explorers who set out for the Pole in expensive armadas of large ships stuffed with years' worth of supplies only to get stuck in the ice. The successful explorers traveled by dog sled and lived off the land. Being able to make fuel abroad for the trip home means astronauts will not have to lug it from Earth, and that means their spacecraft can be light enough to launch with existing rockets. No risky, expensive on-orbit assembly of ''Battleship Galactica'' spaceships.
Economies follow like dominoes.
Part of the fun in reading this book is seeing a crack engineering mind operate. There are enough charts and graphs to tempt the serious student to try to design his own mission. The first Martian homes will be of brick made from Martian sand. If such an arrangement could lead to someone like Bill Gates owning or running Mars, that is not necessarily a bad thing by Mr. Zubrin, who is fed up with how things work on Earth. Bureaucratization, economic stagnation, overregulation, irrationalism, ''Malthusianism'' and the stifling of diversity, he says, are sapping our spirit.