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Orpheus submersible robot to explore the deep ocean

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Orpheus is both the new class of AUV (Autonomous Underwater Vehicle) capable of reaching the ocean’s greatest depths and the first vehicle of the class. Two identical Orpheus AUVs were built in 2018, named Orpheus and Eurydice after the famous pair from Greek mythology who adventured through the depths of Hades. Access to depths below 6000 meters has been historically very limited and fraught with difficulty and risk due to the immense pressures of extreme depths. 1)

Since 2014 and the loss of the hybrid remotely operated vehicle Nereus at hadal depth, the deepest part of the ocean has been closed to systematic exploration and targeted sample collection by researchers. To return science to depths hadal zone in a way that minimizes the risks associated with catastrophic, single-point failure, engineers at WHOI (Woods Hole Oceanographic Institution) in Woods Hole, MA, and NASA/JPL (Jet Propulsion Laboratory) in Pasadena, CA, collaborated to create a networked fleet of hadal AUVs: small, lightweight platforms with a modular design based on the “CubeSat” philosophy capable of being deployed from almost any ship and of reconfiguring their mission parameters on-the-fly.

The design of Orpheus is based on proven technology to minimize construction, shipping, and operational costs that permit it to be launched from small research vessels as well as ships of opportunity. In addition, it incorporates control and mapping software developed by the Jet Propulsion Lab that enables new performance standards than conventional AUV technology and eventually, the ability to reconfigure its objectives on-the-fly. Four fixed-directional thrusters and a compact shape make Orpheus nimble, permitting it to explore near the seafloor, land to collect samples, and lift off again to continue its mission.

Figure 1: Orpheus animation (video credit: WHOI)


Figure 2: Illustration of the Orpheus submersible robot (image credit: WHOI)

Compared to vehicles capable of similar missions, Orpheus vehicles are designed to be widely produced, simple to operate, and deployable from small ships of opportunity, even those that specifically outfitted as research vessels. This design philosophy will enable routine access to a broader community of scientists and explorers. It will also serve as a first step on the path to exploring ocean worlds beyond Earth by conducting missions that serve as analogs for those that might be one day be launched in the ice covered oceans of Europa or Enceladus.

In addition, Orpheus also carries a unique bit of heritage. In 2012, when James Cameron descended to Challenger Deep in the Mariana Trench, he piloted Deepsea Challenger, submersible that was constructed mainly of syntactic foam—a rigid flotation material composed of microscopic glass spheres embedded in epoxy resin. The syntactic foam in Orpheus and its twin, Eurydice came from spare material produced for Deepsea Challenger.


Figure 3: Orpheus was first tested in September 2018 with the ocean exploration organization OceanX and in September 2019 from the WHOI-operated research vessel Neil Armstrong. Each test offered the opportunity to move to successively greater depths and to complete more complex missions (image credit: WHOI)

Development and Status of the Orpheus Project

• On May 14, 2021, the NOAA (National Oceanic and Atmospheric Administration) ship Okeanos Explorer will depart from Port Canaveral in Florida on a two-week expedition led by NOAA Ocean Exploration, featuring the technology demonstration of an autonomous underwater vehicle. Called Orpheus, this new class of submersible robot will showcase a system that will help it find its way and identify interesting scientific features on the seafloor. 2)


Figure 4: The Orpheus submersible robot was developed by Woods Hole Oceanographic Institute and JPL to explore the deep ocean autonomously (image credit: NASA/JPL-Caltech)

- Terrain-relative navigation was instrumental in helping NASA’s Mars 2020 Perseverance Mars rover make its precision touch down on the Red Planet on Feb. 18. The system allowed the descending robot to visually map the Martian landscape, identify hazards, and then choose a safe place to land without human assistance. In a similar way, the agency’s Ingenuity Mars Helicopter uses a vision-based navigation system to track surface features on the ground during flight in order to estimate its movements across the Martian surface.

- Developed by engineers at NASA’s Jet Propulsion Laboratory in Southern California, an evolution of the vision-based navigation that has been used on Mars will now undergo a trial run a little closer to home: off the U.S. East Coast in the Atlantic Ocean.

- Large, high-power location-finding equipment like sonar would normally be required to navigate the dark and often murky waters near the seabed. By utilizing a low-power system of cameras and lights, along with advanced software, Orpheus is an order of magnitude lighter than most deep-sea submersibles. Smaller than a quad bike and weighing about 250 kg, Orpheus is designed to be nimble, easy to operate, and rugged while exploring depths inaccessible to most vehicles.


Figure 5: The Orpheus technology demonstration will be carried out aboard the NOAA ship Okeanos Explorer (image credit: Art Howard/NOAA Ocean Exploration)

- Designed by WHOI in collaboration with JPL, Orpheus can work untethered almost anywhere in the ocean, including the most extreme depths. Ultimately, the project team hopes to see a swarm of these underwater robots work as a team to build 3D maps of the vast regions of unexplored ocean floor in the hadal zone – regions deeper than 6,000 meters. But before the robot can explore these depths, it must first be put through its paces in shallower waters.

Diving Into the Future

- “This tech demo will be used to gather data to demonstrate the viability of terrain-relative navigation in the ocean while also showing how multiple robots will operate together in extreme environments,” said Russell Smith, robotics mechanical engineer at JPL. “These tests will put us on track to start future dives into the hadal zone and intelligently seek out exciting regions of high biological activity.”

- Orpheus’ version of vision-based navigation is called VIO (Visual-Inertial Odometry) and it works by using a system of advanced cameras and pattern-matching software along with instruments that can precisely measure its orientation and motion. As Orpheus travels over the seafloor, xVIO identifies features – such as rocks, shells, and coral – below the vehicle. Like remembering landmarks during a road trip, xVIO will construct 3D maps using these features as waypoints to help it navigate. But this system is more than simply a means to prevent the submersible robot from getting lost.

- The high-resolution maps xVIO creates are stored to memory so that when Orpheus returns to the area, it will recognize the unique distribution of the features and use them as a starting point to expand its exploration. And when working with robot buddies, maps can be shared, cross-referenced, and developed to quickly identify areas of scientific interest.

- “In the future, some of the most extreme ocean environments will be within our reach. From deep ocean trenches to hydrothermal vents, there are many new destinations we will explore,” said Andy Klesh, a systems engineer also at JPL. “By staying small, we’ve created a new, simplified tool for ocean scientists – one that directly benefits NASA as an analogue system for autonomous space exploration.”

- But Klesh noted another virtue of the collaboration between NASA and organizations like WHOI and NOAA, with their extensive oceanographic expertise: The technologies being developed to explore Earth’s oceans with smart, small, and rugged autonomous underwater vehicles could ultimately be harnessed to explore the oceans on other worlds.

- Earth analogues are often used as environmental stand-ins for other locations in the solar system. For example, Jupiter’s moon Europa possesses a subsurface ocean that could host conditions favorable to life.

- “At hadal depths on Earth, the pressures are roughly equivalent to the bottom of Europa’s subsurface ocean, thought to be maybe 80 km deep,” said Tim Shank, the biologist leading WHOI’s HADEX (Hadal Exploration) program. “It is a profound thing to think that this expedition could be the stepping stone to new discoveries about our own planet, including answering that most fundamental question: Is life unique to Earth, or are there other places beyond this pale blue dot where life could have arisen? But before we can explore Europa or any other ocean world, we have to better understand our own home first.”

Expedition Overview

- From May 14-27, 2021, NOAA Ocean Exploration will lead the 2021 Technology Demonstration on NOAA Ship Okeanos Explorer from Cape Canaveral, Florida, to Norfolk, Virginia. The expedition provides an opportunity to test several technologies that will allow the ocean exploration community to explore deeper, farther, and more comprehensively than previously possible. Expeditions like this are vital for the advancement of ocean exploration technologies that will benefit partners and the broader field of ocean exploration alike in our collective mission to explore, map, and understand the vast ocean realm.


Figure 6: Map showing the general operating area for NOAA Ocean Exploration’s 2021 Technology Demonstration (image credit: NOAA Ocean Exploration, 2021 Technology Demonstration)

• March 1, 2019: When the Orpheus drone emerged from the waters off of Cape Cod in September 2018, deep sea biologist Tim Shank felt relieved. Four and a half years earlier, Shank, a scientist at the Woods Hole Oceanographic Institution (WHOI), had sent a state-of-the-art exploration craft to crushing ocean depths — but the vehicle never returned. 3)


Figure 7: The Orpheus drone on the deck of the OceanX exploration vessel, the Alucia (image credit: Ivan Agerton for OceanX and Bloomberg Philanthropies)

- Only shattered pieces of plastic drifted back up to the surface world.

- This time, the new exploration robot Orpheus passed its first test: The machine dove alone into the darkened sea for an hour, without any human control. Critically, the drone came back. Enthusiastic about Orpheus' return, Shank said he fired off an email to his ocean exploration colleague, the filmmaker and deep sea explorer James Cameron.

- "We're back," Shank wrote.

- Scientists from NASA's Jet Propulsion Laboratory and the Woods Hole Oceanographic Institution (WHOI) collaborated to build Orpheus, a small, autonomous robot capable of exploring the deepest, uncharted realms in the ocean — and possibly one day exploring extraterrestrial ocean worlds in our solar system, like the moons Europa and Enceladus.

- In these far-off realms, without a tether linking the robot to humans above, such a craft must be able to explore, map, and photograph these worlds on its own, without a human at the controls. "You let it go and let it run its course," John Leichty, a NASA robotics engineer, said in an interview.

- NASA and Woods Hole's greater scheme is not just to have a single Orpheus capable of visiting uncharted waters, but to have a fleet of them scouring the deep ocean like a school of inquisitive sharks.


Figure 8: A graphic of two Orpheus drones exploring the ocean (image credit: OceanX/Bloomberg Philanthropies)

- On Earth, Orpheus is designed to plunge into the extreme pressures and pitch dark of the ocean's hadal zone — which ranges from depths of 6,000 to 11,000 meters beneath the surface.

- "We have some fundamental questions about who lives there," said Shank. "It truly is an alien world on a non-alien world."

- These uncharted regions are located within the ocean's dark trenches and compose large swaths of the deep central Pacific Ocean.

- During Orpheus' first run in the fall of 2018, the OceanX exploration vessel Alucia left Woods Hole and traveled to waters off of Cape Cod. There, crew members lowered the drone into the water before releasing the tether, allowing Orpheus — which is not yet capable of exploring with complete autonomy — to follow a preprogrammed route some 570 feet under the ocean.

- These ocean endeavors, especially with large vessels like the Alucia, aren't cheap. For the next four years, OceanX and the charity Bloomberg Philanthropies have committed $185 million to Orpheus' research missions, and others.

- Acknowledging that deep sea endeavors are often hampered by funding, Orpheus' engineers intentionally kept the craft small. It measures five feet long and weighs in at around 550 pounds. In contrast, many traditional robotic exploration craft, commonly known as ROVs (Robotic Ocean Vehicles), are around the size of a Volkswagen station wagon, noted Shank. "They're quite massive," he said.

- Building a smaller ocean exploration vehicle is cheaper, easier, and doesn't require a massive ship, explained NASA's Leichty. And for oceans beyond Earth, smaller robots are easier to blast into space.

- Though the hadal zone is inhospitable to most life on Earth, critters there flourish. Shank said that if he lowered a 20-pound mackerel down to these depths, the life teeming in the dark would simply devour the fish over the course of hours. "There would be nothing but bones left," he said.

- Recently-discovered wide-mouthed fish scour the ground, "mud monsters" lay in wait for prey, and shrimp with protracted antennae lurk in the dark water column.

- Orpheus has yet to enter the hadal zone, but the robot's small, nimble frame is designed to survive the pressure here, unlike most ROVs. "The pressures get so great that a normal ROV will collapse," noted Shank.

- And unlike other robotic explorers, Orpheus is designed to land on the deepest ocean floor, 36,000 feet down (~11 km), to sift through the alien ground, gather samples, and carry them back up to the surface.

1) ”Orpheus,” WHOI (Woods Hole Oceanographic Institution), 2018, URL:

2) ”Robotic Navigation Tech Will Explore the Deep Ocean,” NASA/JPL, 14 May 2021, URL:

3) Mark Kaufman, ”NASA dropped a space exploration robot into Cape Cod’s waters to reach the darkest unknowns,” 01 March 2019, URL:

The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: ”Observation of the Earth and Its Environment: Survey of Missions and Sensors” (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (

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