I sing the praise of my robot underlings, the workhorses of deep sea exploration

Building the Remote Lee. Photo by Andrew Thaler

James Cameron’s triumphant dive and (equally important) return from the Challenger Deep is a landmark achievement. In 62 years, only 3 people have ever visited the bottom of the Mariana Trench. While budgets for scientific exploration have been cut across the board, Cameron ponied up tens of millions to build only the second human-occupied submersible capable of reaching those depths. But the Deepsea Challenger is not the only visitor to Challenger Deep in the last few decades. In May, 2009 the ROV Nereus plumbed the depths of Challenger Deep. More than a decade before that, Kaikō, a Japanese ROV, became the first unmanned vehicle to reach into the Mariana Trench and return with video, sediment, and biological samples during several return trips.

And, while Alvin is in drydocks and human-occupied submersibles are tragically being mothballed across the country, more remote operated vehicles are exploring the ocean than ever before. They are being built and run by scientific institutions, private firms, public universities, high schools, industrial corporations, and individual citizens. My lab mate and I built one last winter, for fun. And while I agree with Al and Craig at Deep Sea News that ROV’s are not as “sexy” as human occupied submersibles, that is a marketing problem, because, like it or not, ROV’s are the real masters of deep sea exploration. If your goal is to learn as much as possible about the deep ocean, if you want the biggest return on your investment, if you want to involve a huge and diverse exploratory team, the ROV is king.

That’s not to say that human-occupied submersibles (HOV’s) aren’t important tools in exploration, but there has been a schism in the public discourse, especially in the wake of Cameron’s dive, between ROV’s (and their autonomous brethren, the AUV) and HOV’s, as if these two tools can’t exist simultaneously in the same ocean.

What set me off (and caused me to abandon my forced exile from blogging while I finish my thesis), was this quote:

“If that was not enough, they concluded the segment by pointing out that: “Some scientists question whether you actually need to have humans at the bottom to explore when you can do things like drop down underwater robots”.

This should have been a “walking on the moon” moment with the entire world (and most importantly the entire exploration community) celebrating. If this is true that some scientists really question the need to “Physically” explore the unknown, shame on them! Why go to Mars if we can send a robot? Why meet and talk to people in the flesh if you can do it online?”


Yes, some of us actually do promote ROV’s over HOV’s. No, you don’t need to physically be there to do good, exploratory science. ROV’s provide greater bottom time, can allocate more resources to exploratory and sampling equipment instead of life support, can cover more seafloor, recover more samples, and involve more scientists during a dive. On one of my earliest cruises, we had the opportunity to watch a single deep-sea hydrothermal vent community for 76 hours. You simply cannot do that with an HOV.

One only needs to look to the JASON Project to see the power ROV’s have to inspire the public.

I also challenge the implication that being in an HOV is physically “being there”. You are still confined to a thick steel pressure sphere, with limited view. This isn’t like climbing Everest, you can’t smell the sulfide, feel the heat of the vent, or run you fingers through a garden of tube worms, any more than you could using an ROV. Yes, you are more “there” than with an ROV, and yes, there are real, practical advantages to being in a submersible. You have better control over where you go, you aren’t tethered to the ship, you have depth perception, and you don’t have 35 other scientists breathing down your neck trying to accomplish, other, though complementary, goals. I’m not here to criticize HOVs, I think they are an essential component of deep sea exploration, they provide a broader glimpse into the deep than an ROV allows, and they inspire, which is not an insignificant factor. But the strength of HOV’s does not detract from the strength of ROV’s.

I completely agree with Kevin Z’s sentiment in The Ship, The Sub, The Shuttle – We Should Blame Ourselves. But, while we rejoice in this latest triumph of deep-sea exploration, lets take a step back and not use it as an excuse to dump on our ocean exploration workforce and let’s not shame the scientists that value exploration and discovery using different tools. The versatile ROV is a triumph of human ingenuity, allowing us to broadcast our presence into a world hostile to human life. They genuinely are, as Brian Cox said of the Mars Rovers, “explorers in the old fashion sense.”



  1. Eric · March 29, 2012

    Well said Andrew.

    While I am, perhaps unreasonably, emotionally charged from Cameron’s recent success. You are right the ROV’s are an essential, and often better, tool for exploration. I would ask though, as scientists should we promote one over the other as you have suggested? Wouldn’t it be best to choose the proper tool for the job at hand?

    We should have a discussion on the subtlety of “more there” versus “being there” over drinks some time!

  2. Chuck · March 29, 2012

    An ROV would probably be a safer way to get underwater angry bull shark footage. Wanna go fishing?

  3. Julie Huber · March 29, 2012

    HOVs can’t watch underwater volcanoes explode!


  4. Steve · March 31, 2012

    Hopefully the excitement over Cameron’s trip to the depths will mean more companies are keen to invest in underwater videography! That could be too optimistic but it would be brilliant to get footage of the creatures of the deep and the seafloor formations of some of the world’s biggest trenches – whether by ROV or HOV.

    Obviously the Mariana, being the deepest, gets the glory but as a first-year marine bio student it would be great to have more docos and raw footage from undersea exploration to complement our textbooks.

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