What we know about missing Titanic tourist submersible

During a descent to visit the wreckage of the famed Titanic ocean liner, a submersible craft called the Titan went missing with five people onboard. The vehicle lost communications on Sunday in the North Atlantic Ocean, several hundred miles off Newfoundland.

Rescue efforts are ongoing, but the clock is ticking because reports hold that the submersible carried, at most, enough oxygen to sustain its crew for 96 hours. That might not be enough time, according to Jules Jaffe, a research oceanographer at the Scripps Institution of Oceanography at the University of California, San Diego, who helped find the Titanic in 1985. He worries that the available technologies for potentially locating and rescuing the Titan will not be able to save the craft before its oxygen runs out.

Here’s what to know about the missing submersible, the perils of deep-sea exploration and what could happen next.

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What is the Titan, and where did it disappear?

The Titan is a submersible. That means it’s a small vehicle used for making excursions from another base craft rather than a submarine that has enough power to get to and from port on its own. The Titan is owned by OceanGate Expeditions, a deep-sea tourism company. The vehicle is about 22 feet long and holds a pilot and four passengers—each of whom reportedly paid $250,000 for a ticket to see the famous shipwreck. According to The New York Times, on this expedition, OceanGate CEO Stockton Rush is serving as pilot, accompanied by French maritime expert Paul-Henri Nargeolet, British businessman and explorer Hamish Harding, and British-Pakistani businessman Shahzada Dawood and his son Suleman.

The Titan had hitched a ride to the Titanic’s resting spot—about 400 miles east-southeast off Newfoundland—with a Canadian research ship called the Polar Prince. The latter ship deployed the submersible on Sunday morning. The Titan was last heard from an hour and 45 minutes after starting its descent.

Remote expeditions like this are inherently dangerous, Jaffe says. “You’re all on your own, so if anything goes wrong, you better have enough safety backups to make sure that you can get back out,” he says.

How common are deep-sea incidents like this?

Jaffe says he doesn’t know of other incidents similar to this one, although the U.S. has lost military submarines before. But there simply haven’t been all that many deep-sea expeditions like the Titan’s to start with. The number of people who have visited depths as low as the Titanic’s resting place probably wouldn’t fill a commercial passenger jet.

What’s it like to make a deep-sea dive in a submersible?

One of the people who has visited such depths is Dawn Wright, an oceanographer and chief scientist at a mapping company called Esri. In 2022 Wright visited Challenger Deep, the deepest point in Earth’s oceans at nearly 36,000 feet below sea level. The Titanic itself lies at a depth of 12,500 feet—still remarkably far down. Even on a fast submersible, the descent is a slow process, Wright says. “It’s a beautiful experience,” she adds. “It’s actually very, very peaceful.”

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Wright says submersibles are fully under the control of their pilot, so she herself hasn’t had to do a lot of preparation for her expeditions. This allowed her to focus on scientific observations during the trip to Challenger Deep. “There is a lot to know about the submersible, but there’s not as much as one might think, because you’re putting your life in the hands of the pilot,” Wright says. “You really are a passenger.”

What’s it like at such depths?

At the Titanic’s depth, the ocean is pitch-black and relatively poor in nutrients, so there’s not a whole lot of life or much else to see in most regions, Jaffe says.

The biggest hazard in the deep oceans is the enormous weight of water pushing down on you. Jaffe says that, at the Titanic’s depth, the ocean’s pressure is difficult to comprehend, but he suggests imagining something massive, such as the Statue of Liberty, pressing down on something tiny, such as a penny.

“It’s unthinkable,” Jaffe says. “The only reason organisms can survive at that depth is because they’re more or less the same density as the water around them, so they don’t get deformed like us air-breathing creatures.”

What do you need to make a dive like this safely?

Humans are less dense than surface water (that’s why we tend to float) and thus much less dense than deep water. That means vehicle design is crucial. Deep-sea submersibles are often spherical, or at least their inner chamber is, because the shape helps evenly distribute pressure. Submersibles have traditionally been made of titanium, a particularly strong material, Jaffe says. The worst thing that can happen is for that hull to fail, Wright says. “At those intense pressures, your life ends in a second,” she says. “Everything implodes and you just die instantly.”

Humans on a dive also need oxygen—and the ability to use it efficiently. For instance, Wright says, passengers must be able to stay calm in stressful situations because panicking increases respiration. The vehicle began its expedition Sunday morning with enough oxygen for five people for 96 hours, but there’s no way to monitor at a distance how much oxygen remains. If the passengers can breathe slowly and steadily, they might extend the timeline slightly, according to The New York Times. The vehicle’s battery may also be a factor, according to USA Today, since its power controls the submersible’s temperature in water that can be only a little above freezing.

The easiest way to control the vehicle’s descent and its return to the surface, Jaffe says, is to manipulate its density—for example, with a bladder that can expand and contract. “It’s not hard to get stuff down,” Jaffe says. “Getting the stuff back is the problem.”

Wright says that the communications system is crucial, too. On most of her deep-sea dives, she says, the team sends a robot down first. This helps the submersible navigate and keeps it in touch with the main ship. But Wright says she does not know whether OceanGate uses this kind of technology.

It remains largely unclear what safety precautions OceanGate had taken in this situation. Although universities and military organizations operating deep-sea submersibles likely have strict safety and testing protocols, Jaffe says there’s no international regulation of this type of excursion.

How are deep-sea exploration technologies developing?

Deep-sea submersibles are still cutting-edge technology themselves, Wright says, noting that the vehicle she rode was one of only two submersibles in the world that can safely reach Challenger Deep.

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“One of the biggest technological advances is this ability to go anywhere in the ocean,” Wright says. “The real advancements are in these vehicles and instruments that can withstand the hydrostatic pressure—it’s the destructiveness of the pressure in the ocean that is a major impediment.”

Within a submersible, battery advances are particularly important. Researchers are also developing better deep-sea lighting systems and mapping technology to support expeditions, she says.

Where could the Titan be, and how are people looking for it?

Jaffe says he sees three potential scenarios for the missing submersible. The best-case scenario is that it was able to shed weight and rise to the surface of the water. The vehicle would still be difficult to find, given local weather conditions—on Wednesday, waves were expected to reach nine feet amid low clouds and fog, according to The New York Times—but airplanes flying over might be able to spot it.

The other scenarios are grimmer, Jaffe says. “The best thing would be if they’re on the surface,” he adds. “I think rescue from the seafloor or mid-water is going to be extremely difficult, even if we knew where they were.”

If the Titan is indeed stranded in “mid-water,” or around the middle third of the water column, that would require ships to survey the area using sonar, Jaffe says. Sonar would easily detect anything floating in the water column, he notes, but ships equipped with this technology would move slowly, and they would need to survey a large area of water.

The Titan could also be stuck on the bottom of the ocean. “If they’re sitting on the seafloor, that’s probably the worst news,” Jaffe says. To begin with, there are few vehicles that can reach the Titanic’s depths. Even if the search-and-rescue teams have one, the lost submersible would be difficult to locate—after all, it took several missions to find the much larger Titanic itself in 1985. And the successful expedition needed a week of searching to locate the shipwreck.

If the submersible is on the seafloor, it might blend in with the Titanic’s own debris field, Jaffe notes. “If it’s sitting on the bottom, I don’t know any quick way to find it in a clutter field like the Titanic,” he says.

What is it about the Titanic that inspires such tourism?

The Titanic and its wreckage have long fascinated people, Jaffe says, thanks to its glamour—and the fact that some 1,500 people died when it sank. “It was a monumental ship that we thought was indestructible, and what we found out was that we are still vulnerable to forces on this planet that are beyond our control,” Jaffe says.

That symbolism has drawn people to the site since its discovery, and both Jaffe and Wright say they’re glad to see adventurers take to the deep seas. Wright compares the Titanic shipwreck to a national park on land—places where both science and tourism thrive. “The hope with the Titanic wreck was that it would be more of a sacred site that people would visit, that would be protected from treasure hunters,” Wright says.

“But there’s also great dangers here,” she adds. “It’s like the people who try to climb El Capitan in Yosemite: That’s something that you can do; it’s a wonderful thing to do. But it’s an incredibly dangerous thing to do.”