A one‑legged robot that jumps instead of rolls could help scientists explore the icy geysers on Saturn's moon Enceladus, sampling material from a hidden ocean that may be friendly to life.

The early mission concept, known as LEAP — short for Legged Exploration Across the Plain — imagines a robot about one-foot tall and weighing roughly 2 pounds. Rather than driving like a Mars rover, LEAP would use a spring‑driven leg, a pair of wheels, and internal spinning "reaction wheels" to roll, tip itself upright, and launch into long, arcing hops.

Funded by NASA's Innovative Advanced Concepts program, the LEAP project builds on a real-world prototype, called SALTO. Though it looks like a little pogo stick — or Pixar's boinging lamp — its jumping action actually takes inspiration from squirrels. (If that's not cute enough, imagine scientists collecting data from squirrels with high-speed cameras while the critters traverse a homemade parkour course.) The researchers published their results in Science Robotics last year.

Whether the hopping robot ever reaches Saturn will depend on mission choices still years away. But you can watch the little robot do its thing in a new video just released by NASA further down in this story. 

Enceladus has become a prime target in the search for life beyond Earth. Beneath its bright ice crust lies a global ocean. Near the south pole, deep fractures nicknamed "tiger stripes" vent that water into space as plumes of ice grains and gas. Those jets give scientists a rare advantage in the outer solar system: They can sample ocean material without drilling through miles of ice.

Reaching those jets is not straightforward. The region around them looks fractured and uneven, with steep ridges, broken ice fields, and powdery material. Other options, like aircraft, have limits as well, said Justin Yim, a mechanical science and engineering assistant professor at the University of Illinois at Urbana-Champaign.

"Conventional rovers may struggle to navigate this rugged terrain. Flying poses its own challenges," said Yim at the 2025 NASA's Innovative Advanced Concepts symposium. "Enceladus has no atmosphere, and the use of rocket-based propulsion [would risk] contaminating samples. It is in this context that we find jumping to be uniquely promising."

Because Enceladus has extremely weak gravity — about one-eightieth of Earth's — a relatively small push can send an object traveling far. Researchers estimate LEAP could travel roughly 560 feet — close to the length of two American football fields — in a single hop and rise about 300 feet into the air.

Each jump would play out in slow motion compared with Earth. That long airtime is central to the design. It would allow the robot to pass directly through a plume while in flight. A single hop could last close to a minute, with several seconds spent inside the icy spray.

During that time, onboard instruments could analyze ice particles, measure composition, and capture data on how the plume behaves. Contrary to popular belief, more legs wouldn't necessarily improve its jumping performance, Yim says.  

"One is a great number for jumping, particularly because it has this great advantage of allowing you to concentrate your actuation in one very powerful and simpler design," he said at the symposium last year. "Multiple legs give you a lot of benefits for doing things like sitting or standing on the ground, but you could do those equally well with wheels."

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LEAP's two wheels and one leg give it three points of contact, which makes the robot stable in that position as well, he said.

The robot would likely ride to Enceladus aboard a larger spacecraft that first orbits the moon and then lands, a setup often described as an Orbilander. From that base, LEAP could deploy, make repeated jumps between vents, and go beyond the landing zone.

But before any mission becomes real, engineers still need to demonstrate that the system can survive Enceladus' extreme cold, which reaches about minus -330 degrees Fahrenheit, and test how its foot behaves on unfamiliar ice. Most development will have to happen through simulations and lab testing.

"It's going to be difficult to get the same type of conditions we'll have on Enceladus," Yim said. "It's extremely, extremely cold, and the type of ice particles we'll encounter there are probably very different from what we'd see in natural environments on Earth."