Earth is heavy. Lifting cargo in space from Earth is expensive due to gravity. Numbers:<p>Earth escape velocity: 11,000 m&#x2F;s, energy to propel 1kg to escape velocity: 60MJ.<p>Moon escape velocity: 2,400 m&#x2F;s, energy to propel 1kg to escape velocity: 3MJ.<p>Moon based interplanetary travel is 20 times more efficient than Earth based interplanetary travel. A robotized Moon base would make economic interplanetary travel a whole lot cheaper. Step 1 for a Moon base is landing on the Moon, so I wouldn&#x27;t dismiss Apollo just yet. Perhaps they were 100 years ahead of the times, but their heart [and mind!] was in the right place.