Charles Elachi is the director of NASA's Jet Propulsion Laboratory, where he oversees space exploration programs such as the Mars Rovers.

Tweeting (and covering Bowie) from the International Space Station last year, Colonel Chris Hadfield reminded the world how much we love space.

Engineer and daredevil cave explorer Bill Stone is obsessed with discovery -- on Earth and beyond.

Megan McArthur is a mom, explorer and NASA astronaut. She has orbited the Earth 197 times and logged more than five million miles in space, so far.

Jon Nguyen is an award winning aeronautics and graphics engineer at NASA.

To determine how life might persist on Mars, Nathalie Cabrol explores one of Earth’s most extreme environments: high-elevation Andean lakes and deserts.

Stuntman and record-setter Steve Truglia was a stunt coordinator, performer and action unit director in the UK.

Alan Eustace leapt to Earth from the edge of the stratosphere wearing only a spacesuit, shattering skydiving records and potentially revolutionizing the commercial space industry.

Carrie Nugent is part of a team that uses NASA's NEOWISE telescope to search the skies for and catalog asteroids.

Melodie Yashar develops construction technologies to allow us to build on the Moon and, one day, Mars.

TED Senior Fellow Alexander MacDonald develops strategies to advance space exploration and encourage private-sector space activities.

As the leader of the Imaging Team on the Cassini mission to Saturn, Carolyn Porco interprets and shares the pictures coming back from this fascinating planet, its rings and its moons.

In 2004, legendary spacecraft designer Burt Rutan won the $10M Ansari X-Prize for SpaceShipOne, the first privately funded craft to enter space twice in a two-week period. He's now collaborating with Virgin Galactic to build the first rocketship for space tourism.

Xavier De Kestelier is an architect and technologist with a passion for human space exploration.

As manager of the Rosetta mission, Fred Jansen is in charge of the project that could be instrumental in uncovering clues to the origins of life on Earth.

Taking cues from bottom-up biological networks like those of social insects, Radhika Nagpal helped design an unprecedented “swarm” of ant-like robots.

Lucianne Walkowicz works on NASA's Kepler mission, studying starspots and "the tempestuous tantrums of stellar flares."

Harry Cliff looks for answers to questions about the origins of the universe and the laws of nature.

Peter Diamandis runs the X Prize Foundation, which offers large cash incentive prizes to inventors who can solve grand challenges like space flight, low-cost mobile medical diagnostics and oil spill cleanup. He is the chair of Singularity University, which teaches executives and grad students about exponentially growing technologies.

Lynn Rothschild is passionate about the origin and evolution of life on earth or elsewhere -- while at the same time pioneering the use of synthetic biology to enable space exploration.

Phnam Bagley designs the future of everything, on and off planet Earth.

Aomawa Shields studies the climate and habitability of planets outside of the Solar System.

Fascinated by exploration both on and off this planet, Nadia Drake writes and thinks about both the very big (astronomy) and the very small (spiders).

Nagin Cox explores Mars as part of the team that operates NASA's rovers.

James Green leads NASA's solar system exploration and astrobiology research.

Honor Harger explores the cultural impact of scientific ideas and how technology shapes society.

Natalie Panek's work is focused on the idea that accountability for our environments never goes away.

Cady Coleman draws from her time at NASA and her missions on the International Space Station to share insights about team building, leadership and innovation.

Jennifer Heldmann spearheads robotic and human exploration of the solar system, with an eye to answering the central question: "Are we alone?"

Dustin Schroeder develops and uses geophysical radar to study Antarctica, Greenland and the icy moons of Jupiter.