Multiple factors were involved in the decision of exploration of Mars.
Mars is similar to Earth in size and it is the next planet. Moreover, evidence was present to suggest that liquid water existed, and may possibly still exist, on Mars. All of these factors led to the planet's exploration.
Mostly, after WWI, Britain promised them their current stretch of land in the Middle East. While Britain did not deliver, this did give them their claims, and their holdings were secured in WWII and further legitimized in the current war on terror.
He created new federal agencies to deal with specific needs of the troops and home front
