When your laptop or your smartphone gets hot, you know it's crunching a lot of data. So you can imagine the amount of heat generated by the racks upon racks of servers that store and process the world's digital lives. Keeping these data centers cool is such a problem that tech companies like Facebook and Google prefer to move them to colder countries than pay the air conditioning bill. But for Microsoft, there's an even better home for all that data: under the sea.

Microsoft's prototype server ran for 105 days

This morning, Microsoft unveiled Project Natick — an ongoing research project into subsea data centers that could be both cost effective and environmentally friendly. The company started exploring the idea in 2013 after Microsoft data center employees wrote a white paper about the concept (one of the authors had experience on a navy sub). Development of a physical prototype began in 2014 and in August last year, the company deployed its first ever submarine server — a steel capsule some eight foot in diameter — off the coast of California. It ran for 105 days in total, with Microsoft's engineers saying it was more successful than expected.

"When I first heard about this I thought, ‘Water ... electricity, why would you do that?’" Ben Cutler, a computer designer for Microsoft who worked on the project, told The New York Times. "But as you think more about it, it actually makes a lot of sense."

The Natick team (from left to right: Eric Peterson, Spencer Fowers, Norm Whitaker, Ben Cutler, Jeff Kramer) with the prototype server. (Image credit: Microsoft)

Placing data centers underwater not only helps keep their contents cool, but also has logistical advantages. Microsoft points out that half of the world's population lives within 200 kilometers of the ocean, making subsea systems potentially easier to deploy when extra capacity is needed. The company also believes that if it can mass produce the capsules it could set them up in just 90 days — much quicker than the two years needed to build a data center on land. Engineers involved in the project even believe that one day, subsea data centers might be able to power themselves using underwater turbines or tidal power to generate electricity.

It's an attractive idea, but there are obviously plenty of challenges, not least of all the difficulty of creating data centers that can survive without regular checkups. Data centers on land are open for engineers to fix and replace servers whenever needed, but Microsoft wants its undersea systems to go without maintenance for years at a time. "We see this as an opportunity to field long-lived, resilient data centers that operate 'lights out' — nobody on site — with very high reliability for the entire life of the deployment, possibly as long as 10 years," says the company.

Leona Philpot being christened by the Natick team. (Image credit: Microsoft)

Microsoft's first prototype, named Leona Philpot after a character from Halo, contained only a single computing rack sealed in pressurized container filled with nitrogen. More than a hundred different sensors were used to monitor conditions inside and outside the capsule, says The New York Times, with Microsoft's engineers keeping an eye on conditions like humidity, pressure, and motion. The sensors also measured the capsule's impact on its environment — although thankfully, the sounds of the server's fans were drowned out by the noise of nearby shrimp, while the heat it generated only affected the water a few inches around the vessel.

Obviously the project is still in the early stages of development, but Microsoft says it's the right time to start rethinking data centers. Not only is demand for data growing as cloud computing becomes more popular, but the slowing of Moore's Law (the observation that computing power doubles roughly every two years), means that servers are less likely to become outdated. Microsoft is already working on its next step — an underwater system three times the size of the Leona Philpot — with the company expecting to start new trials some time next year.