Elon Musk wants people to get to Mars for $200,000 a ticket. A new crop of space entrepreneurs want to make it much, much cheaper.

Tim Ellis, co-founder of Inc. 30 Under 30 winner Relativity Space, spoke Wednesday at the Wall Street Journal Future of Everything Festival in New York. He was joined by TransAstra founder Joel C. Sercel. 

Relativity Space manufactures rockets in an innovative way: via 3-D printing. Ellis says the company has built the world's largest 3-D metal printer, which it can use to manufacture large parts that would normally consist of many smaller components. Already, it has built an engine comprised of just three total parts--a far cry from the 2,700 that would normally be required.

While most rockets take more than a year to build, the company wants to be able to do so in just 60 days. In theory, this will make getting to space much cheaper: Ellis says that labor comprises 80 to 90 percent of the cost of rocket manufacturing.

SpaceX, which Musk founded in 2002, was one of the first private companies to  revolutionize the space business with its reusable rockets. Musk believes that technology will ultimately make it more feasible to get humans to Mars. The Red Planet is an ambition that Ellis shares with Musk--and he hopes other entrepreneurs do as well. "We believe," Ellis says, "that there needs to be dozens to hundreds of companies working on this." 

The startup, which has $45 million in funding, has the ultimate goal of being the first company to 3-D print a rocket on Mars. By that time, he thinks, the space industry will have exploded, thanks to the decreased cost of building the vessels for getting there.

"I can very confidently make the bet," Ellis says, "that over time, everything that flies will be 3-D printed."

Sercel, whose company wants to mine asteroids for propellant, also believes the space industry is on the brink of an awakening. While the field is growing rapidly, it's still about a $330 billion industry globally--less than the revenue of Walmart. "This is going to become a multi-trillion dollar industry over the next several years," Sercel predicts. 

TransAstra is one of several companies that wants to mine asteroids for resources. Planetary Resources, founded by Peter Diamandis, wants to pull minerals and water from space rocks. Silicon Valley-based Deep Space Industries has similar goals--and wants to use those resources to build a city in space. The general concept behind such startups is that launching a rocket from space will greatly expand the distance it can travel, since it won't burn fuel battling the pull of Earth's gravity.

"If you can get to low earth orbit, you're halfway to anywhere in the solar system," Sercel says, crediting the theory to science fiction writer Robert Heinlein. "You think space is exciting now? It's just getting started."