The Exploration of Mars is the third and final book resulting from the 1952...54 series of articles in Collier's, edited by Cornelius Ryan. In the article series the expedition to Mars was a monstruous affair, 70 scientists and technicians in ten ships to Mars, actually a scenario drawn up by von Braun in the years 1948-50, and published as such elsewhere. In 1956 the connection with Ryan was broken, a new partnership with Walt Disney was developing and the team Ley-von Braun resized the Mars Expedition to 12 men in 2 ships. Also resized were the launch vehicles needed to get the material and propellants for the ships off the ground and into Earth orbit.
Used availability for Wernher von Braun's The Exploration of Mars