The idea of rocket reusability isn't new. But until SpaceX, no space organization has actually attempted to make it a reality. After 13 years of working on the problem, SpaceX CEO Elon Musk believes the company is getting closer.

SpaceX Falcon 9, designed for reusability. Image source: SpaceX.

Musk shared an update on the space company's plans during an interview at the 2015 Baron Investment Conference. 

Rocket reusability isn't easy
"People have thought about reusability for a very long time," Musk said during the interview. The problem, however, is that it's a fundamental battle with physics.

"It just happens that earth's gravity is quite strong, and it's just barely possible to get a reasonable payload to orbit with an expendable rocket, so then if you add reusability, then that tends to give it negative payload to orbit," Musk explained.

But Musk believes the company is getting close to advancing its rocket technologies far enough to where SpaceX could achieve a net payload to orbit even with effective reusability, which would make reusable rockets possible.

"We haven't yet achieved it. I think what we've done thus far is evolutionary -- not revolutionary," Musk said. But the CEO remains optimistic: "I think we're within, sort of, shooting distance of this. I think within the next year, we'll be able to land the rocket intact."

One of the company's recent failed attempts was well publicized. SpaceX returned a rocket from space to a barge in the ocean, and just before what looked like it would have been a successful landing, the rocket tipped and exploded.

"We've been able to land the rocket -- just not intact," Musk added jokingly, noting there are some "exciting videos on YouTube if you want to watch them."

Challenges beyond landing
There are, of course, many critics of reusability. And it has less to do with the possibility of successfully landing a rocket and more to do with the condition of a spacecraft after a launch. Doubters argue that even if rockets could be reused, the resulting stress from a trip to space would render the spacecraft subpar for future missions.

Musk acknowledged this challenge during the interview, noting that after SpaceX lands a rocket "intact," the company will then have to examine the rocket for potential improvements.

There will likely be plenty more work for SpaceX after the first successful landing before reusability becomes a reality.

But the upside for SpaceX if it achieves reusability is enormous. Reusability would be revolutionary to the economics of space launch services. As Musk explained during the interview, the cost of its rockets are around $60 million, but the cost of the propellant is only about $250,000 to $300,000 -- "about as expensive as fueling up a 747," Musk noted.

If SpaceX can achieve reusability, the company would completely disrupt one of the most important industries of the future.