NASA engineers have spent the past decade developing a rugged, partially autonomous lander designed to explore Europa, one of Jupiter’s most intriguing moons. The space agency got cold feet over the project, but engineers are now targeting a new destination for the probe: Enceladus.

Europa has long been a prime target in the search for extraterrestrial biology because scientists suspect it harbors a subsurface ocean beneath its icy crust, potentially teeming with microbial life. But the robot—packed with radiation shielding, cutting-edge software, and ice-drilling appendages—won’t be going anywhere anytime soon.

In a recent paper in Science Robotics, engineers at NASA’s Jet Propulsion Laboratory (JPL) outlined the design and testing of what was once the Europa Lander prototype, a four-legged robotic explorer built to survive the brutal surface conditions of the Jovian moon. The robot was designed to walk—as opposed to roll—analyze terrain, collect samples, and drill into Europa’s icy crust—all with minimal guidance from Earth, due to the major communication lag between our planet and the moon 568 million miles (914 million kilometers) away.

Designed to operate autonomously for hours at a time, the bot came equipped with stereoscopic cameras, a robotic arm, LED lights, and a suite of specialized materials tough enough to endure harsh radiation and bone-chilling cold. Temperatures on the moon range from about -210 degrees Fahrenheit (-134 degrees Celsius) at its equator to as low as -370 degrees F (-223 degrees C) at its poles.

After years of development—including testing in JPL’s labs, advanced simulations, and a final field trial on icy terrain in Alaska—the Europa Lander aced its tests. It was ready to take on the solar system’s frosty frontier. But the space agency has now pulled the plug on the mission.

According to the team, the challenges of getting to Europa—its radiation exposure, immense distance, and short observation windows—proved too daunting for NASA’s higher-ups. And that’s before you take into consideration the devastating budget cuts planned by the Trump administration, which would see the agency’s funding fall from $7.3 billion to $3.9 billion. The lander, once the centerpiece of a bold astrobiology initiative, is now essentially mothballed.

But the engineers aren’t giving up. They’re now lobbying for the robot to get a second shot—on Enceladus, Saturn’s ice-covered moon, which also boasts a subsurface ocean and has proven more favorable for robotic exploration. Enceladus is still frigid, but has lower radiation and better access windows than Europa.

Whether the ice-walker gets a new lease on its semi-autonomous life remains to be seen. But the robot was built for a moonwalk—albeit a relatively rigid and clanky one—and it deserves its moment.