The Future of Humanity

For decades, launching a rocket meant throwing away, on every trip, equipment that cost hundreds of millions of dollars. Kaku shows how the arrival of private companies in the space business changed that math: rockets that land back on Earth and can be reused have pushed down the price of putting cargo into orbit.

This drop in cost opens the real possibility of sending people beyond low Earth orbit on a bigger scale than a one-off flag-and-footprints mission. The book calls this a new space age: it's no longer just a handful of hand-picked astronauts, it's the beginning of an industry.

It's like comparing the price of an airline ticket in 1960, when flying was a luxury, with a sale fare today: the technology didn't change the destination, it changed who can afford to get there.

Some asteroids that pass near Earth carry rare metals, like platinum and gold, in amounts that would rewrite the price of those metals if brought to market all at once. The book describes projects that aim to send robotic probes to identify and, eventually, extract this material, with no astronauts on board.

The logic is similar to a gold rush, except the probe has to fly out to a rock moving at thousands of miles per hour. Water trapped as ice inside asteroids could also become rocket fuel in space, which avoids hauling everything up from the ground.

Kaku is clear that this is still a medium- to long-term promise, not an industry running today. The biggest obstacle isn't technical, it's economic: extracting the material and bringing it back costs more than the metal is worth.

The Moon appears in the book as a springboard, not a final destination. A base there would serve to test survival technology in a hostile environment, with radiation, abrasive dust, and two-week nights, only three days from Earth instead of the months that separate us from Mars.

The book describes the idea of using ice in permanently dark craters at the lunar poles as drinking water and, split into hydrogen and oxygen, as fuel. That would make the Moon a refueling stop, not a place that has to receive everything ready-made from Earth.

For Kaku, mastering lunar logistics is the dress rehearsal before the riskiest trip, the one to Mars. A mistake close to home costs days. A mistake on the way to Mars can mean months before help arrives.