Researchers are preparing to send an unmanned drone into Superior Maximus, the deepest point in the Great Lakes, for the first time in 40 years. The dive is planned for 1 p.m. Saturday and could run through Tuesday if weather cooperates, with the exact launch time to be announced shortly before liftoff.

The expedition will be livestreamed, giving viewers a chance to watch the descent into a place 1,300 feet below the surface of Lake Superior where no light reaches and the pressure is 40 times what it is at the top. Bridge Michigan is co-hosting the broadcast, and Shawn Sitar, Yvonne Drebert and Zach Melnick are set to answer questions from the public as the team explores a part of the lake most people will never see in person.

That timing is why the search is spiking now. The dive is not just a rare trip into a deep basin; it is also part of Hidden Below: The Great Lakes, an upcoming documentary built around freshwater exploration rather than the better-known ocean kind. The team will use a Boxfish Luna underwater cinematography drone to look for deepwater sculpin, forests of colourful hydra, mysis shrimp and siscowet lake trout.

For researchers, the appeal goes beyond images. Shawn Sitar said the deepest waters act as a long-term record of what is happening in the ecosystem, and studying them helps explain how energy and nutrients move through Lake Superior and how the ecosystem responds to change. That matters now because scientists have recently found siscowet trout in poor shape for reasons they cannot yet explain.

The fish are supposed to be chunky, but some have turned up with skinny bodies and large heads, and their deep habitat has made the problem harder to untangle. If the expedition finds siscowet trout at Superior Maximus, it could add another clue to that mystery; if it does not, the absence may be just as revealing about what lives in the lake’s darkest water.

Drebert said the Great Lakes are often mistaken for something emptied out and lifeless, when in fact there is a vibrant world under the waves that is still there for anyone willing to look for it. She also said the livestream is meant to hear from Michiganders and others around the Great Lakes about what they are seeing, whether they are surprised and whether they notice something the team has missed. The next real milestone is Saturday’s launch window, and the only thing researchers can promise before then is that the exact moment will come shortly before the drone goes down.

If the weather holds, the first unmanned look at Superior Maximus in four decades will not just reopen a long-closed window on Lake Superior. It may also show whether the lake’s deepest water can help explain why some of its trademark trout are suddenly coming up thin.