NASA Underwater Robots: Advancing Ocean World Missions

Underwater robots, shown here during a Caltech pool test in September 2024, may one day navigate subsurface oceans on icy moons. Image: NASA/JPL-Caltech.

Underwater robots are an essential part of modern oceanography, and their importance is set to increase in the coming years. However, the challenges faced by underwater robots are numerous, and their development is a complex and ongoing process. 

What challenges do underwater robots face, what has NASA developed, and what does the future of underwater robots look like?

The Challenges of Extraterrestrial Oceans

The search for life in the universe has long been a driving force behind scientific research. While scientists continue to explore the possibility of life beyond our solar system, numerous candidates within our own solar system hold great promise. 

Mars, for instance, has been a prime target for researchers despite the fact that any life that may have once existed there is now extinct. Instead, researchers rely on fossil records to gather clues about the planet's past. Other potential candidates for harbouring life include bodies with oceans and lakes, such as Titan and Europa. 

Mars and Other Ocean Worlds 

These environments are ideal for the formation of life due to the presence of liquids, which are essential for the development of living organisms. However, unlike the oceans on Earth, exploring these extraterrestrial bodies presents a multitude of challenges that must be addressed. 

One of the primary challenges faced by researchers is the vast distance between Earth and these celestial bodies. As a result, any platforms or missions sent to explore these environments must be fully autonomous and capable of identifying and recognising objects of importance. This level of autonomy is crucial, as communication with Earth is often delayed due to the immense distance between the two bodies.

Furthermore, the lack of real-time communication means that the platform must handle any mission failures or unexpected events independently. Another considerable challenge is gaining access to the oceans and lakes on these bodies. In the case of Europa, the liquid water beneath the kilometres of ice poses a major hurdle for researchers. 

The ice crust not only acts as a barrier to accessing the subsurface ocean but also presents a notable risk to any mission attempting to land on the surface. The extreme conditions on Europa, combined with the potential for catastrophic ice collapses, make it a formidable target for exploration. 

Overcoming the Barriers of Ice-Covered Oceans 

The harsh conditions of space also pose a noticeable threat to any mission attempting to explore these extraterrestrial bodies. The extreme temperatures, radiation, and debris in space can all take a devastating toll on spacecraft and landing craft, leading to mission failures. 

The risk of damage is further compounded by the fact that these environments are often inaccessible, making it impossible to send a rescue team to repair or retrieve a damaged mission. In addition to the technical challenges posed by exploring these environments, there are also numerous logistical and financial considerations that must be taken into account. 

The cost of launching a mission to another planet or moon can be prohibitively expensive, making it essential for researchers to carefully plan and prioritise their missions. The logistical challenges of transporting personnel and equipment to these environments also present a notable hurdle, particularly for longer-term missions that may require resupply and maintenance. 

NASA exploring underwater robots for future exploration

Recently, NASA has announced the development of underwater robots capable of exploring the depths of our solar system's ocean worlds. The mission, dubbed SWIM, is currently in the testing phase, with the latest prototype demonstrating autonomous control and navigation in a swimming pool at Caltech in Pasadena. 

NASA's innovative SWIM concept leverages advanced technology inspired by oceanographic research here on Earth. The integration of autonomous features in the underwater robots mirrors advancements seen in terrestrial autonomous underwater vehicles (AUVs), which are used to explore deep-sea environments. By repurposing Earth-based methodologies for extraterrestrial exploration, NASA is bridging the gap between proven scientific practices and space-age innovation.

Earth-Based Innovations Repurposed for Space

According to NASA, the SWIM team has been working on the development of these underwater robots for several years, with the ultimate goal of sending them to the subsurface oceans of icy moons such as Europa and Enceladus. The robots, approximately the size of a cellphone, are equipped with propellers and flaps for steering and are designed to operate independently, without human intervention. 

This emphasis on autonomy reflects a significant step forward in reducing mission risks associated with human intervention. Drawing parallels with self-driving technologies, the SWIM robots rely on intricate algorithms and real-time data processing to adapt to unforeseen challenges under icy extraterrestrial waters. This adaptability is essential for missions targeting Jupiter’s Europa or Saturn’s Enceladus, where environmental unpredictability is a major concern.

The latest prototype, measuring 16.5 inches in length and weighing 5 pounds, was tested in a swimming pool at Caltech in September 2024. The robot successfully demonstrated controlled manoeuvring, the ability to stay on course, and a back-and-forth "lawnmower" exploration pattern. The robot also spelled out "J-P-L" during one of the tests, indicating its ability to perform complex tasks autonomously.

Real-World Testing and Progress 

These controlled manoeuvres are a direct outcome of iterative testing and refinement. NASA’s engineers have employed rigorous pool tests to simulate the unique pressures and currents expected in Europa’s subsurface oceans. By replicating similar conditions during these trials, the team ensures the robots are not only technically sound but also capable of executing complex search patterns critical to finding biosignatures.

The SWIM team has also developed a digital version of the robot, which has been tested in computer simulations. These simulations helped determine the limits of the robots' abilities to collect scientific data in an unknown environment and led to the development of algorithms that enable the swarm to explore more efficiently. 

The use of simulations also provides insight into optimising resource allocation among the swarm. Each robot is programmed to perform distinct tasks, ranging from mapping water currents to identifying hotspots of chemical activity. Such specialisation within the swarm ensures maximum efficiency, a necessity given the limited operational lifespan dictated by power constraints.

Digital Simulations to Enhance Efficiency

In addition to the underwater robots, the SWIM team has also developed an ocean composition sensor that enables each robot to simultaneously measure temperature, pressure, acidity or alkalinity, conductivity, and chemical makeup. This sensor, which is only a few millimetres square, is the first to combine all these sensors in one tiny package. 

The compact design of this sensor underscores a broader trend in miniaturisation, allowing for the integration of multifaceted instruments within small robotic frameworks. By equipping SWIM robots with these cutting-edge sensors, researchers can gather a wealth of data simultaneously, ranging from thermal gradients to chemical anomalies—key indicators in the search for extraterrestrial life.

While the SWIM mission is still in its early stages, it has the potential to reshape our understanding of the ocean worlds in our solar system. The use of underwater robots to explore these environments could provide scientists with valuable insights into the possibility of life beyond Earth and help us better understand the conditions necessary for life to exist. "We're trying to figure out how to make these robots work in the most challenging environments in the solar system," said Ethan Schaler, principal investigator for SWIM. "It's a really hard problem, but we're making progress, and we're excited about the possibilities."

Potential Impact on Understanding Ocean Worlds 

Beyond technological achievements, missions like SWIM also serve as a platform for developing collaborative expertise across disciplines, from astrobiology to robotics engineering. This convergence of knowledge not only enhances the mission's chances of success but also contributes to Earth-based applications, such as improving underwater exploration techniques and advancing AI for autonomous systems.

How Could Autonomous Swimming Robots Change Exploration?

The development of autonomous robots capable of navigating oceans and lakes is a crucial step towards expanding our exploration capabilities, particularly for ocean worlds. If NASA can perfect these robots, it will significantly impact how we gather data and conduct research in the vast and uncharted regions of our oceans and beyond. 

One of the most important advantages of such autonomous robots is their ability to operate independently from human operators back on Earth. This means they can react to events and objects of interest in real time without needing delayed responses. As a result, they can capture valuable data on any phenomenon that arises, providing scientists with a wealth of information that would otherwise go unnoticed. 

Real-Time Data Collection for Rapid Discoveries 

For example, underwater volcanoes that erupt or marine life that migrates to specific areas can now be studied in greater detail, thanks to the ability of autonomous robots to identify and investigate these events. The use of autonomous robots also enables the exploration of areas beyond the communication range. This is particularly crucial for deep space missions, where signal delays can last 20 minutes or more. 

With autonomous robots, scientists can send probes to distant planets and moons, allowing them to collect data and conduct experiments without needing to wait for responses from Earth. This not only accelerates the pace of scientific discovery but also enables us to explore regions that were previously inaccessible due to communication technology limitations. 

The ability of autonomous robots to navigate complex environments also opens up new possibilities for exploration. For example, underwater robots can be used to map the seafloor, identifying areas of interest such as hydrothermal vents or shipwrecks. These findings can then be used to inform future missions, ensuring that the most valuable targets are prioritised. 

Mapping Uncharted Terrains with Precision 

Similarly, autonomous robots on other planets can identify areas of geological interest, such as impact craters or fault lines, which can provide valuable insights into the planet's history and evolution. The use of autonomous robots also has crucial implications for the field of astrobiology. 

As we continue to search for life beyond Earth, autonomous robots can play a critical role in detecting biosignatures. By navigating through the oceans of distant planets and moons, these robots can identify signs of life, such as unusual chemical signatures or patterns of biological activity. While we have yet to find definitive evidence of extraterrestrial life, the use of autonomous robots will undoubtedly help us get closer to answering this age-old question. 

Overall, the development of autonomous robots capable of navigating oceans and lakes is a crucial step toward expanding our exploration capabilities. By enabling real-time data collection, exploring areas beyond communication range, and identifying areas of interest, these robots will help us uncover the secrets of our oceans and beyond. As we continue to push the boundaries of space exploration, the use of autonomous robots will undoubtedly play a critical role in our quest to understand the universe and our place within it.