The Gravity Gang was a group of geniuses--devoting its brilliance to creating a realistic Solar System for Disneyland. That was the story, anyway. No one would have believed all that stuff about cops and robbers from outer space.
The story is set in 2158 A.D., after the invention of a medicine called Anti-Gerasone, which is made from mud and dandelions and is thus inexpensive and widely available. Anti-Gerasone halts the aging process and prevents people from dying of old age as long as they keep taking it; as a result, America now suffers from severe overpopulation and shortages of food and resources.
The flight into space that made Pilot-Capt. Dan Barstow famous. He was one of the very first astronauts to leave the earth -- and what he found surprised even him. "Another world." Small and too dark to see from the earth -- but large enough to capture his spacecraft. Large enough to get trapped on it.
Two miles of American front had gone dead. And on two lone infantrymen, lost in the menace of the fog-gas and the tanks, depended the outcome of the war of 1932.