This August when the Arctic ice breaks, Parks Canada will work in partnership with other government agencies and private sector organizations to launch the biggest expedition yet to find the lost ships HMS Erebus and HMS Terror that were on Sir John Franklin’s last fateful voyage in the 1840s.

“Finding the ships would be one of the biggest stories in the world,” says Ryan Harris, a senior marine archeologist with Parks Canada and the person in charge of most of the technology used in this year’s search.

The vessels sailed from England in May 1845 in search of the Northwest Passage. But the ships and their 129-person crew disappeared somewhere in Canada’s North, with the exact location remaining a mystery that continues to captivate many. Eventually, the details of the crew’s grim demise emerged, but the ships were never found.

Harris says new additions to this year’s search tools should more than double the area that has been scoured in previous years, greatly increasingly the chances of finding the two shipwrecks.

Parks Canada’s underwater archaeology team and most of their equipment is housed in a building in Ottawa, far from chilly Arctic waters. In the team’s staging area, there is a bewildering jumble of cameras, screens, fibre optic cables, sonar systems and self-guided underwater robots.

There’s also the autonomous underwater vehicle or AUV, a new piece of equipment the team will be using this year. Around two metres long, it’s a sleek yellow mini-submarine that two people can drop from a zodiac. Harris says the AUV operates like a “puppet without the strings.” Harris says the self-guided robot zips back and forth in precise patterns like a lawn mower. Because it operates under the waves and isn’t connected to a bobbing boat, it isn’t affected by turbulent water, allowing the search to continue when seas are too rough for traditional side-scan sonar.

Sonar works by shooting sound waves at the sea floor and measuring how long it takes the waves to bounce back. The resulting data helps create a picture of the seafloor that is detailed enough to pick out a wreck. But if it’s too wavy, the images from side-scan sonar become distorted and unusable. Given the capricious northern weather, relying only on the side-scan sonar could mean days of precious time wasted. With the AUV, delays can be avoided.

Harris is also excited about a second, unique AUV that Defence Research and Development Canada are lending to the search.

“The star of the show this summer will be the Arctic Explorer,” he says. The 7.5-metre, 2,000-kilogram Explorer is three times the size of Parks Canada’s AUV. It’s the main reason the team is expecting to cover more ground than last year. It can scan 300 metres to either side, three times as much as Parks Canada’s AUV, and it produces better images.

But even with the two AUVs, high definition cameras to examine anything they find and years of planning and experience, Harris is still cautious.  “These waters are essentially uncharted. We know far more about the surface of Mars, Venus and the moon than we do of the sea floor in the Canadian Arctic.”