Researchers first presented their proposal to NASA in 2017, revealing a boxy lander that would study both the surface and what’s below. The team didn’t need confirmation of the mission to get started — there have already been tests for its data antenna.

The moon is potentially the best candidate for life in the Solar System beyond Earth. Europa has a crust covered in water ice (there’s even evidence of sea salt). If there’s a corresponding water ocean underneath the surface, NASA might find evidence of life — even if it’s just the remnants of an earlier era. Clipper could also help determine the viability of human exploration of Europa, although any prospect of that is many years away.

The Clipper team is assessing its performance in the electromagnetic test facility’s controlled environment, much like how the Mars helicopter team used JPL’s Space Simulator to prove their unmanned flying vehicle works. In particular, they’re making sure it’s highly accurate when it comes to pointing to its targets, since that’s the key to sending back high-resolution images and huge volumes of scientific data.

“The measurements that will be performed in the ETR will demonstrate that the Europa Clipper mission can get a large volume of scientific data back to Earth and ultimately determine the habitability of Europa,” said Thomas Magner, Europa Clipper’s assistant project manager.

Scientists believe the moon’s thick, icy crust is hiding a global salty ocean. A NASA official once said that it’s one of the “most promising places that could potentially harbor life in the solar system” outside of our own planet and is definitely worth a visit.

While the Clipper team is almost done with its current round of tests, they’re planning to conduct more in the same facility before the spacecraft blasts off. The Europa Clipper is expected to launch sometime in 2020 and will take three to seven years to reach the gas giant, depending on its launch vehicle and other factors.