Engineers are testing a robotic prototype for an ambitious mission concept in a competition pool - a team of underwater explorers searching for signs of life on an alien ocean world. NASA's upcoming mission to Europa will deploy advanced robots to detect life in its icy ocean. The robots, part of the SWIM project, have been rigorously tested on Earth and through simulations to cope with extraterrestrial conditions.
Exploring Europa: NASA's ambitious mission
When NASA's Europa Clipper arrives at Jupiter's moon Europa in 2030, it will use a powerful suite of scientific instruments to conduct 49 flybys to search for evidence that the ocean beneath Europa's icy crust could harbor life. The spacecraft was launched on October 14 and is equipped with the most advanced science and technology ever sent to the outer solar system. However, even as it begins its mission, NASA teams are already designing the next generation of robotic probes to explore deeper into Europa's hidden oceans and beyond to advance scientific discoveries.
One of the innovative concepts is called SWIM, which stands for "Swimmer Independent Microwave Sensing." The project envisions deploying a swarm of tiny self-propelled robots, each about the size of a mobile phone. The robots will be sent beneath the surface of the ocean by an ice-melting cryobot. Once released, they spread out to explore, looking for chemical and temperature signals that might point to the presence of life.
"People might ask, why is NASA developing underwater robots for space exploration? It's because we want to look for life in certain parts of the solar system, and we think life requires water," said Ethan Schaler, SWIM principal investigator at NASA's Jet Propulsion Laboratory in Southern California. "So we need robots that can autonomously explore these environments hundreds of millions of miles from home."
In development at the Jet Propulsion Laboratory, a series of prototypes of the SWIM concept were recently tested in a 25-yard (23-meter) competition swimming pool at Caltech in Pasadena. The test results are encouraging.
The SWIM team's latest iteration is a 3D printed plastic prototype that relies on low-cost commercial motors and electronics. Powered by two propellers and four flaps, the prototype demonstrated controllable maneuverability, the ability to maintain and correct course, and a back-and-forth "lawnmower" exploration mode. All of this is done autonomously without direct intervention from the team. The robot can even spell "J-P-L."
The robot was tethered to a fishing line just in case, and during each test an engineer trotted by the pool with a fishing rod. Nearby, a colleague used a laptop to review the robot's movements and sensor data. The team completed more than 20 rounds of various prototype tests in a swimming pool and two water tanks at JPL.
"It's great to build a robot from scratch and see it operate successfully in an environment," Schaller said. "Underwater robots in general are very difficult, and this is just the first in a series of designs we're working on in preparation for traveling to the ocean world. But this proves that we can build these robots with the necessary capabilities and start to understand what challenges they face when performing underwater tasks."
Towards autonomous ocean exploration
The wedge-shaped prototype robot used in most pool tests is about 16.5 inches (42 centimeters) long and weighs 5 pounds (2.3 kilograms). As envisioned for spaceflight, the robot would be about three times smaller in size - minuscule compared with existing remotely controlled and autonomous underwater science vehicles. These palm-sized swimming robots will use miniaturized specialized components and a new wireless underwater acoustic communications system to transmit data and triangulate positioning.
Digital versions of these little robots have also been put to the test themselves, not in swimming pools but in computer simulations. A swarm of 5-inch-long (12-centimetre-long) virtual robots repeatedly searched for potential signs of life in an environment with the same pressures and gravity that might be encountered on Europa. Computer simulations help determine the limits of a robot's ability to collect scientific data in unknown environments and help develop algorithms that enable swarms of robots to explore more efficiently.
The simulations also helped the team better understand how to maximize scientific return while considering the trade-offs between battery life (up to two hours), the volume of water a swimmer can explore (about 3 million cubic feet, or 86,000 cubic meters) and the number of robots in a single swarm (a dozen, sent in four to five waves).
Additionally, a collaborative team at Georgia Tech in Atlanta built and tested an ocean composition sensor that allows each robot to simultaneously measure temperature, pressure, pH, conductivity and chemical composition. Measuring just a few millimeters square, the chip is the first to integrate all these sensors in a tiny package.
More information about SWIM
SWIM is a NASA innovation project managed by Caltech's Jet Propulsion Laboratory (JPL) and funded by NASA's Innovative Advanced Concepts (NIAC) program. The project envisions a swarm of small autonomous swimming robots exploring the subsurface oceans of icy moons like Europa, looking for signs of life. Transported by ice-melting cryobots, the cellphone-sized robots will spread out to detect chemical and temperature signals that could indicate habitability or life.
Supported by Phase I and II funding from NASA's Space Technology Mission Directorate NIAC, SWIM is part of an initiative to evaluate cutting-edge technologies that could transform future missions. Researchers from the U.S. government, industry, and academia are encouraged to submit proposals for the program to advance aerospace and space exploration.
Compiled from /ScitechDaily