When he talks up the ambitious projects on the drawing board at JPL, he describes the place as a sort of intellectual and engineering combat zone. One where complex designs and the successful execution of missions are the result of brilliant scientists and engineers bashing their ideas against each other.

"We're known for having a very intellectually aggressive culture," he laughs. "I just came out of an all-day review yesterday with people from outside, from NASA headquarters, and they were chuckling at times because our interaction can be such a full-bore, bare-knuckled brawl."

Small wonder, given the scope of some of the projects JPL has on the docket at the moment.

Steltzner's current responsibilities include serving as chief engineer for the Mars 2020 project -- a plan to send another rover to the red planet in 2020, this time with instruments that will collect samples of rock and soil and hermetically seal them for a future mission that will retrieve them and bring them home. That project will also offer a deeper look at the potential for life on Mars, Steltzner explains, by characterizing the geology and habitability of the Mars environment and to help prepare it for eventual human exploration.

The design of the Mars 2020 rover is based in part on that of Curiosity, the rover for which Steltzner a few years ago oversaw the team that designed the hardware for the "entry, descent and landing" phase. It was such a technical achievement -- sending a vehicle hurtling through space and setting it down gently on the Mars surface -- that Steltzner has published a book about Curiosity, called The Right Kind of Crazy.

Working on Curiosity in the JPL Spacecraft Assembly Facility

It details some of the challenges, setbacks and high-stress moments that came with the development of Curiosity's Sky Crane landing system. That undertaking, he writes, taught him and his team a lot -- that engineering tasks are dependent on "honestly facing the hard data," and that in an organization as sprawling and complex as NASA, the best problems are "too complicated to have a clean equation that describes them."

Meanwhile, he's got plenty more to keep him busy. Steltzner's also working on a new kind of parachute that would help carry humans to Mars, and developing robotics systems that will be used to explore Europa and Enceladus -- the moons of Jupiter and Saturn thought to have the best chance of hosting alien life.

"Here's what I believe to be true," Steltzner tells Engadget. "Our human curiosity is one of our greatest attributes, and an outgrowth of that curiosity is our desire to explore that which we do not know. I don't have something like a great business model about why we should explore space -- in fact, there's an old aerospace adage that goes, 'The way to make a small fortune in aerospace is to start with a large one.'

"What I do know is that when we explore, it makes us better. It makes us bigger, and that is profound. Think about that. What is the effect culturally, societally, if everybody sits just a tiny bit taller because of something we do here? That's not to be undersold. It's difficult to quantify. I can't give you 'Oh, the GDP goes up by 1 percent when everyone is inspired to be a little more and to try to do a little more,' but the effect is profound."

The mysteries of the galaxy are indeed so profound that they convinced a young man who grew up in Sausalito, California, playing bass for several bands, to do something different with his life.

Coming home from a gig one night, Steltzner found himself preoccupied by the distinct and changing patterns of the stars he saw above him. He'd never shown much of a predilection for science and math as a student, but even so, something nagged at him -- to the point that he decided to enroll in a nearby community college, signing up for a physics course.

He transferred to the University of California, Davis, after a few years and ended up majoring in mechanical engineering and design. It was the start of a preoccupation with the stars that's shaped his career and ultimately brought him to NASA, to a coterie of like-minded space geeks working to explore the next frontier.

"It's a big deal," Steltzner says of Mars 2020. "It's part of the science community, where every 10 years we do a survey and ask a research council, 'What should we be doing?' They've been telling us we need to bring samples back from Mars, so that's on track now. It's actually a great opportunity, because we're leveraging a lot of the heritage and spare parts from the Curiosity rover.

"We just finished our PDR, our preliminary design review, at the beginning of [February], and we're steaming ahead. There are a couple hundred people working on a wide range of activities and efforts. As chief engineer, I float. I spend almost all my time sitting in a room talking to other people about a technical problem. About trying to understand if we have a staffing shortfall. I look for holes and fill them myself if I can, or get people to move into jobs and move on to the next hole. I'm sort of a free safety, as it were."

Founded in 1936, today JPL is managed for NASA by the California Institute of Technology. It has a workforce of more than 5,000 and got $250 million for the Mars 2020 rover as part of the latest NASA budget Congress approved.

One thing that helps keep interest alive in the organization's planned expeditions is how deeply a fascination with space has seeped into the zeitgeist. It also helps that private companies have emerged and begun to score thrilling successes on their own, with custom rockets and launches that become splashy media events.

For his part, Steltzner says he's enthusiastic about private space ventures like Blue Origin and SpaceX.

"I love the privateers -- I absolutely l-o-v-e love them," he says. "Because they're willing to do things differently. They're invigorating space. Having said that, the challenge they face is in the end, eventually, someday they have to answer to investors who want them to be profitable endeavors. And that may someday exhaust their energy. But bring it on. Adam Smith was right: Competition is really important."

So is keeping the public excited about space. It's why JPL recently commissioned a beautiful series of retro-looking space-themed travel posters, created in partnership with Seattle-based design firm Invisible Creature. "Visit the Historic Sites ... Mars ... Multiple Tours Available," reads one, presenting rockets in flight and designed in a way that makes you think you could be looking at the creation of a Madison Avenue ad shop in the '50s.

It's also why Steltzner wrote his book. He insists that the sustainability of the human race depends on our willingness to pursue schemes that sound crazy but are "the right kind of crazy" -- things like sending rovers to Mars that could pave the way for eventual human habitation of the planet.

"We explore as a gesture of humanity," he writes. "We do it because we can, and we do it as an affirmation of who and what we are. As a society, if we ever stop exploring, who will we be? I think we will be stagnant -- not innovating, not building. It's a formula not just for stagnation but for disaster. Which is why nurturing and supporting innate curiosity is still one of the most valuable survival tools we have."