Into the Unknown: How Similar Is Deep Sea and Space Exploration?

Both the deep sea and space are difficult to reach and even more difficult to explore. You can’t breathe the air, temperatures are extreme, gravity varies, and atmospheric pressure makes survival impossible without protective vehicles. It’s part of the reason that these remote terrains are largely left unexplored. Only a minuscule portion of the universe and 5 percent of the ocean floor have been visited.

Both deep sea travel and deep space travel come with a lot of risks and a lot of preparation, but when it comes to the nitty gritty, how similar are these two remote worlds?  

According to David Klaus, a professor of aerospace engineering science at the University of Colorado Boulder, the fundamentals and preparation of deep sea and space travel are very similar. Both sea and space require bringing along water, food, and oxygen, as well as the removal of contaminants like urine and feces.  

The biggest difference between space and the deep sea is that in space you’re pressurized from the inside out and under water you’ve got all the pressure on the outside. And in both cases, you have to maintain the atmosphere with the right amount of pressure, temperature, and humidity. 

“The fundamental functions are, for all practical purposes, the same, but the difference is in how you meet those functions,” says Klaus.  

Read More: What Comes After Oceangate?

When you’re underwater, you can always come up to the surface (even though it might take a few minutes) to resupply, and the same is true of low Earth orbit, where you can resupply with more water, food, and other goods being sent up to the Space Station. If a broken part needs to be repaired, that can happen in low Earth orbit but not in deep space.  

When you’re traveling to deep space, for example, to Mars, the time lag adds another layer of danger. It takes a minimum of six months to fly to Mars, depending on where you are in the Earth’s orbit.  

“The time lag for communication in deep space can be up to 44 minutes roundtrip, which means if something life-threatening is happening, there’s nothing a ground crew can do to help,” says Klaus. He adds that this drives the need for autonomous decision-making that you wouldn’t necessarily have in low Earth orbit or in the deep sea.   

We know from the Titan submersible that there’s a real risk of implosion when it comes to deep sea exploration. The Titan submersible imploded in June 2023 with five passengers on board. The implosion likely occurred during the vehicle’s initial descent, killing the passengers instantly. Other risks of deep sea exploration include entanglement on the sea floor and fire in the cabin.   

By far, the biggest risks in space travel are launch and reentry, when the largest amounts of energy are expended. But there’s also the risk of space radiation, which happens beyond the protection of the Earth’s magnetic field. 

According to NASA, “high-energy galactic cosmic rays and solar storms” can harm the body or damage spacecraft. What’s more, isolation from Earth can be risky if an astronaut encounters an accident or has a life-threatening health problem while aboard a spacecraft. Over time, gravity can also be harmful to the body, weakening bones and muscles.   

While both the deep sea and space offer a new frontier of exploration, each poses its own set of challenges and risks. And with all that goes into exploring these remote worlds, it’s no wonder that there’s still so much more to explore both on Earth and in space.  

Read More: How Long-Term Space Travel Wears Down an Astronaut’s Mind and Body

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• NOAA. Most of our ocean is unexplored.

• NOAA. How much of the ocean has been explored?

• United States Coast Guard News. Titan Submersible Marine Board of Investigation

• National Geographic. Expedition Risks and Dangers

• NASA. Hazard: Space Radiation

Sara Novak is a science journalist based in South Carolina. In addition to writing for Discover, her work appears in Scientific American, Popular Science, New Scientist, Sierra Magazine, Astronomy Magazine, and many more. She graduated with a bachelor’s degree in Journalism from the Grady School of Journalism at the University of Georgia. She's also a candidate for a master’s degree in science writing from Johns Hopkins University, (expected graduation 2023).