It happened so fast that for a minute he just stood there absolutely incapable of taking it in. One instant the big Earth-Venus rocket freighter was sizzling through the fog to a perfect landing on the field below. Then suddenly she dipped, undershot the field and vanished in a flash and a thundering explosion that shook the observation tower. In the dream-like quiet that followed, Dan Kearns heard the faint yells of the landing crew. He saw the big searchlights switch on, cutting wide swaths of