The used rockets of tech billionaires just might save humanity from doom -- here's how

Elon musk watching falcon 9 rocket launch landing natgeoNational Geographic/YouTubeElon Musk watches a historic Falcon 9 rocket launch and landing on December 21, 2015.

The way Elon Musk sees it, humanity is either on the cusp of its greatest revolution — or risking its own annihilation.

But now, after 15 years of work through his rocket company, SpaceX, Musk’s rosier scenario┬ámay have finally started to take root.

On March 30, SpaceX proved it can launch satellites, cargo, and eventually people into orbit around Earth using previously flown Falcon 9 rocket boosters.

The technology could make obsolete an industry-wide practice of trashing multi-million-dollar rockets after every launch, drastically lowering the cost of access to space in the process.

“This is a very helpful proof point that it’s possible, and I hope people start to think of it as a real goal to which we should aspire, to establish a civilisation on Mars,” Musk told Business Insider during a post-launch press teleconference. “This is not just about humanity, it’s about all the life that we care about.”

Musk’s SpaceX isn’t the only company working on reusable rocket systems: Blue Origin, a company owned by founder Jeff Bezos, is also in the game.

Here’s what the future of reusable spaceflight might soon look like, why Musk and others are pushing hard for it, and what it might mean for our species’ future.

Rockets are currently our only way to get anything off the planet, including satellites, supplies for the International Space Station, and people.

A Falcon 9 rocket built by SpaceX launches the SES-10 satellite on March 30, 2017.

But just one orbital rocket costs tens of millions of dollars to build, and for decades we've trashed them after each use.

Russia's Soyuz MS-01 spacecraft launches from the Baikonur Cosmodrome in July 2016.

Source: Business Insider

Except for the payload, everything falls back to Earth and burns up in the atmosphere, sinks into the ocean, or crashes onto the ground.

Source: ESA/YouTube

Bezos has said it's like flying a 747 across the country once -- then throwing the plane away.

Drew Angerer/Getty Images
Jeff does not approve of this.

Source: ABC News

Musk on Thursday compared discarding expensive rocket parts to loading up a pallet with millions of dollars of cash, flying it, and letting it shred up on its way back down instead of attaching a parachute to it.

Breaking Bad

That's why Musk's SpaceX and Bezos' rocket company Blue Origin have developed reusable rockets.

Blue Origin
Blue Origin's New Shepard reusable rocket system, which is designed to take tourists on suborbital flights.

Instead of throwing away tens of millions of dollars every single launch, reusable rockets can fly over and over again. The only cost per Falcon 9 launch would be a few replacement parts and about $200,000 for rocket fuel.

Like many orbital rockets, each Falcon 9 is made of two main stages. The first-stage booster does most of the work and represents about 70% of a rocket's cost.

The main parts of SpaceX's partly reusable Falcon 9 rocket system.

First, the giant 229-foot-tall rocket launches from a pad near the sea.

A Falcon 9 rocket built by SpaceX launches SES-10 on March 30, 2017. It was the world's first reuse and relanding of a used orbital-class rocket.

Its thrust is powerful enough to loft two Hubble Space Telescopes into orbit by burning RP-1 (a type of kerosene) with liquid oxygen and blasting it out through nine huge rocket engines.

A Falcon 9 rocket launches with cryogenic fog trailing it into the sky on January 14, 2017.

After flying dozens of miles above Earth, the rocket separates into two parts. The first-stage booster begins to fall back down while the second stage -- which carries the payload -- ignites its single engine.

SpaceX/Flickr (public domain)

You can see the second stage continues on into space. But thrusters on the first stage fire to flip the booster around and point its engines back toward Earth.

SpaceX/Flickr (public domain)

Next, some of the engines on the booster briefly reignite to line the rocket up for a landing. Small grid fins open on the sides to help it steer.

SpaceX/Flickr (public domain)

Once the rocket gets close to Earth, the engines light again to help it slow down before the landing. The grid fins help keep the rocket oriented in the right direction.

SpaceX/Flickr (public domain)

A sophisticated navigation system tells the rocket where to land. When it works, the rocket can land on a droneship, which can be easily be towed back to a coastal space center.

SpaceX has attempted to land its rocket on a barge at sea before. Some of the early tries ended... explosively.

Note: Sped up 2X.

But they eventually got it right. And on March 30, 2017, SpaceX re-launched a booster it had landed about a year before, proving the full cycle works.

'This is potentially revolutionary,' John Logsdon, a space policy expert and historian at George Washington University's Space Policy Institute, previously told Business Insider. 'Reusability has been the Holy Grail in access to space for a long, long time.'

Jeff Bezos' rocket company Blue Origin has also successfully landed, refueled, and relaunched a rocket. It's impressive.

Called New Shepard, Blue Origin's rocket system is suborbital -- meaning it can only get a ship to the edge of space (roughly 62 miles above Earth).

The plan is to sell tickets to adventurous passengers, who can experience zero gravity for a few minutes as they fall back to Earth.

Here's what the New Shepard's space capsule may look like on the inside.

A sneak peek at the final design of Blue Origin's New Shepard capsule for suborbital space tourists.

But Blue Origin's current rocket isn't powerful enough to put a spacecraft or satellites into orbit. That requires nearly 1,000 times more energy.

SpaceX's Falcon 9 rocket is capable of orbital flight, landing, refuelling, and relaunch. Musk hopes to shrink the time between launches to roughly 24 hours, which he hopes could reduce spaceflight costs 100-fold.

But Musk says SpaceX will fly a much bigger rocket, called Falcon Heavy, at the end of summer in 2017. Blue Origin also has its gigantic reusable New Glenn rocket in the works.

Blue Origin/Dave Mosher, Business Insider
How Blue Origin's New Glenn, SpaceX's Falcon, and NASA's Saturn V rocket systems compare.

Which means both SpaceX and Blue Origin will soon be able to send spaceships, cargo, and people back to the moon...

The famous 'Earthrise' photo taken by Apollo 8 astronauts during their trip around the moon on Dec. 24, 1968.

...And eventually on to Mars. Musk would like to try an uncrewed landing on the red planet before 2020.

But he'd like to reduce the cost of access to space 1,000-fold, and eventually 10,000-fold. That, Musk says, would enable SpaceX to sell the first Mars colonists a one-way ticket for $A263,000 or less.

He plans to do this through a 400-foot-tall (122-meter-tall) fully reusable vehicle called the Interplanetary Transport System.

His engineers are already building and testing parts for his gigantic Mars rockets, like this enormous carbon-fibre fuel tank -- the largest ever made, and around which his spaceship will be built.

The tech mogul's ultimate vision is this: Send a million people to colonize Mars and turn it into a 'backup drive' for humanity.

His belief is that if humanity doesn't ruin the planet itself, an unbelievable catastrophe like an asteroid strike will.

An illustration of comets and asteroids striking planet Earth.

Large extinction events regularly occur on Earth. In fact, we have about a 1-in-75,000 lifetime chance of dying from an asteroid impact, or nearly twice as high as dying in an earthquake.

An artist's rendering of an asteroid swarm.

Source: Business Insider

Musk doesn't expect to be around by the time his 'insurance policy for humanity' is secure. And he doesn't think it will be easy to get there -- but says we must try, or risk eventual extinction.

Kevork Djansezian/Getty Images

'We have to figure out not just how to do this technology, but without going bankrupt,' Musk said on Thursday. 'Before we're dead, and before the company is dead.'

Getty Images/ Scott Olson

Disclosure: Jeff Bezos is an investor in Business Insider through his personal investment company, Bezos Expeditions.

Business Insider Emails & Alerts

Site highlights each day to your inbox.

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.