Casey Machado is used to searching for alien life. As a research engineer for the Woods Hole Oceanographic Institution (WHOI), she’s designed many of the submarines that sift through the deepest reaches of the oceans, searching for new species. Of course, the crabs and fish discovered at these depths are only alien to humans. To find the real extra-terrestrials, WHOI’s subs are going to have to boldly go where no sub has gone before.
“The extra-terrestrial vehicles will explore the ocean worlds of our solar system, much like how the Mars rovers explore the surface of Mars,” she says. Top of the list of nearby water worlds is Europa, the ice-encrusted moon of Jupiter. Thought to harbour vast oceans kept fertile by volcanic activity, Europa’s ice sheets have long been a favourite destination to start looking for life elsewhere in our solar system. And with help from Nasa and other partners, Casey’s team at WHOI are busy designing the first submarine to explore this alien aquarium.
But before it can take its first space swim, the WHOI’s prototype must be tested on Earth. And for an otherworldly Europa replica, the team knew the perfect spot: the hadal zone – the ocean’s deepest, least explored level.
“The hadal zone in Earth's ocean provides a surprisingly good analogy to the pressures and conditions found on Jupiter's moon Europa,” says Casey. “So the technical solutions we achieve through collaboration further both exploration here on Earth, as well as beyond.”
Named after Hades, the god of the underworld, the hadal zone fits its hellish namesake. Pressed between sheer trenches, water temperatures stay within a biting 1-4°C, and at its lowest level the zone’s pressure is equal 1,100 tonnes of weight being placed on a human body. Ranging in depths from 6,000 to 11,000 metres and covering an area the size of Australia, it’s not an easily accessible diving spot, even for submarines. Which is why WHOI’s latest underwater vehicle, Orpheus, is so exceptional.
“The quality that sets Orpheus apart from previous hadal exploration vehicles is its emphasis on enhancing routine access to the hadal zone,” says Casey. “It’s a fraction of the cost of the much larger submersibles, at less than $200,000, and is more than ten times smaller, too.”
Despite resembling an orange fridge with a Zimmer frame, Orpheus is part of a whole new class of autonomous underwater vehicles. The prototype is small, lightweight, and capable of scanning the deepest, gloomiest crevices of the hadal zone. But with the weight of the ocean above it, how doesn’t it crack under the pressure?
“Every part of the vehicle must either be strong enough to survive individually, or placed into a strong, sealed one-atmosphere enclosure for protection,” explains Casey. “While metals provide an intuitive choice for this protection, they’re heavy and expensive to fabricate typically, which went against our aims of smaller, more accessible solutions.”
Considering that Orpheus’ decedents may one day be loaded onto a rocket and blasted into space, a heavy sub is a luxury the team can’t afford. “As an alternative, we use a 17" diameter glass sphere with a wall thickness of about half an inch,” Casey adds. “While fragile in some aspects, glass is fantastic when being uniformly compressed, and if made into a spherical form, it can withstand the pressures at the deepest trenches. Inside this sphere, we keep our computers, cameras, and batteries safe, allowing us to use every-day, commercially available technologies.”
But while some of Orpheus’ kit may be standard, other technologies are more space-grade. Control and mapping software developed by Nasa's Jet Propulsion Laboratory gives the slim sub a higher degree of manoeuvrability than its conventional cousins – an ability that could come in handy when traversing the ice-encrusted oceans of Europa.
Orpheus’ debut dive took place outside Cape Cod Bay in September last year. The drone successfully dived 176m before returning to the surface. While a mere paddle in the shallows compared to the depths of the hadal zone, the test was proof enough for the team to progress with their grander plans, which include an autonomous armada.
“We hope to work with our collaborators at Nasa's Jet Propulsion Laboratory to develop autonomy and algorithms to enable the Orpheus class of hadal vehicles to explore intelligently and cooperatively alongside other vehicles and the researchers that operate them,” says Casey. Able to communicate with each other kilometres down into the seas, the proposed fleet of Orpheus subs could vastly accelerate science’s understanding of the secretive hadal zone.
“The part I find most compelling about the project is that with only a couple hundred thousand dollars for a vehicle and a chartered small fishing boat, anyone could conceivably contribute to the exploration of the deepest trench in the world,” adds Casey. “We hope that kind of accessibility will be tremendously empowering to the oceanographic community.”
Like the intrepid Mars rovers before them, the WHOI’s fleet of sleek submarines could one day explore the uncharted territories of another world, pushing the very boundaries of science to a new frontier. But before setting off to oceans new, the armada of drones will explore the still mostly unmapped hadal zone. Europa may be on the horizon, but beneath the waves lie aliens of our own.
This article was originally published by WIRED UK
