UNIVERSITY Master’s degree in biology from the California Institute of Technology; bachelor’s degree in biology from StanfordUniversity

RESEARCH/INNOVATION Using bacteria to act as biological sensors to detect chemicals or infectious materials; the ability of some strains of bacteria to tolerate arsenic, and the genes involved.

AWARDS Permission to Dream Award, Space Frontier Foundation; Todd B. Hawley Space Visionary Award, InternationalSpaceUniversity

Loretta Hidalgo was 10 years old when she discovered her passion for biology in space. She was on a ride in the EpcotCenter’s plant-filled land pavilion, and she saw a hollow cylinder that contained lettuce growing around a light bar. “It was supposed to simulate a lettuce-growing system for space, and they had to spin it to simulate gravity,” says Ms. Hidalgo, now 31. “I thought it was cool.” She studied biology as an undergrad, and specialized in astrobiology in graduate school. She wanted to figure out how to grow food in space, and how to cycle air and water to allow a crew to stay in space sustainably.

But the research she wanted to do didn’t exist. She had worked at NASA’s JohnsonSpaceCenter in Houston and at the NASAAmesResearchCenter in Moffett Field, California, where she researched arctic plants and studied the possibility of building greenhouses on Mars. At the California Institute of Technology, she studied bacteria. But “the space program wasn’t going fast enough,” she says. “It was not going at a pace where anyone would need bio-regenerative life-support systems in my career.”

So she left Caltech early—with her master’s degree, not her Ph.D.—and became a “space activist” working to accelerate the space pace. She is the president of the Space Generation Foundation, an all-volunteer nonprofit that promotes space exploration and education. Last year, she worked for the X Prize Foundation to help organize the events surrounding the $10-million prize that inspired Scaled Composites’ SpaceShipOne to make two trips into suborbital space. Ms. Hidalgo is also a flight attendant for Zero Gravity, a company that offers people zero-gravity experiences on a 727 cargo jet, and was part of the team that explored the bottom of the ocean in James Cameron’s Aliens of the Deep.

Ms. Hidalgo thinks everyone should have the chance to experience space, and believes the Next Big Thing will be commercial space flights—both orbital and point-to-point suborbital transportation (think San Francisco to Japan in one hour.) The “blank slate” of space brings a broader perspective and more global thinking, she says. “I think it inspires people and brings people together. It’s awe-inspiring, it’s disarming… and it brings down people’s barriers.”

Ms. Hidalgo says it’s only a matter of time before we find life in space, and she thinks humans will eventually live somewhere else besides Earth. She still hopes to work in a food-growth lab in space one day.

But in the meantime, she will continue advocating and educating people about space. “When I was a kid, people said in the year 2000 we’ll be flying around in jet packs and stuff,” she says. “One thing I’ve learned is the future has to be built; it doesn’t just happen. Unless somebody stands for it and fights for it, and gets all the people around them excited about it, it won’t become real. We’ve got to take charge and make all this happen.”