Inc.'s 11th annual 30 Under 30 list features the young founders taking on some of the world's biggest challenges. Here, meet LuminAid.

The year 2010 had just begun when Anna Stork sat down next to Andrea Sreshta in a design studio at Columbia University. The goal of studio time was for each student to embark on, and eventually complete, a thesis project--perhaps the architectural plans for a shopping center or a model of a skyscraper. But both women had trouble concentrating from the get-go: They couldn't stop thinking about the earthquake that had ravaged Haiti just days earlier.

They teamed up. They shared an interest in experimenting with solar power and wanted to create a project that could help victims of natural disasters. Within a few months, they'd scraped together recycled materials and purchased some electrical components from and Radio Shack. They hand-prototyped an inflatable lantern, powered by a rechargeable battery and solar power.

"We used bottle caps for the valves, and hand-sealed the plastic ourselves," Stork says. The following year they filed for patents of their inventions--and with that, they set up a company called LuminAid.

LuminAid's namesake rechargeable solar-powered LED lantern inflates like a balloon and collapses to become thinner than a deck of cards--meaning it takes up much less space than the smallest dependable flashlight. To mountain climbers, it's a popular piece of cool gear. But to first responders and victims of natural disasters, it's more than that.

Light is not just a necessity for cleanup, cooking, and moving about after dark; it also provides safety. As Kerri Murray, the chief executive of ShelterBox, a nonprofit that distributes LuminAid lanterns to disaster-relief sites, explains: "When you have tent camp situations after a crisis, energy and light are fundamental needs. The camp can be a very dangerous place, particularly for women and children, and having lighting can reduce the risk of sexual assault."

In their first year, Stork and Sreshta launched an Indiegogo campaign to fund the manufacturing of a batch of the lights. They weren't expecting to find market validation simultaneously, but they did. "We raised five times our original goal, and all of a sudden we had customers--and a lot more than we thought," Sreshta says.

More than 50,000 LuminAid lanterns have been deployed across 70 countries, to refugees and in disaster zones including those for Hurricane Sandy in 2012, Typhoon Haiyan in 2013, and 2015's Nepalese earthquakes. The lanterns are made of nontoxic waterproof plastic--and they float.

Over the past five years, Stork and Sreshta have grown the business slowly, broadening its product offerings to more efficient lanterns with greater capabilities (they now make three varieties, including the PackLite 16, which can provide 30 hours of continuous light after a seven-hour charge) and partnering with more NGOs to distribute lights while continuing online sales. They have funded their efforts through entering--and winning--a number of university pitch contests and startup competitions. They even signed up online to be on Shark Tank.

And last February, they were. They'd practiced their pitch hundreds of times--and it worked. All five of the investors onstage wanted to back LuminAid, to the tune of at least $200,000. After a moment of dramatic whispering out of Shark earshot, they decided together: Mark Cuban would be their investor.

And, turns out, Shark Tank gave them a new lease on the business, Stork says. They saw a significant boost in online orders when the show aired, and they now have anticipated 2016 revenue of $5 million. More recently, for a Shark Tank update, Stork and Sreshta flew to Malawi with their customer ShelterBox. "It was our first time seeing the light in use by people truly in need. It was very touching and motivating," Stork says.

There may be challenges ahead, such as continuing to develop new and innovative products and managing a complex international supply chain. But "the experience of seeing our lights being used in Malawi will definitely motivate us for the next couple of years," Stork says.