NASA’s groundbreaking Juno spacecraft has only just successfully arrived in orbit around Jupiter, but we already know its fate. In 2018, the spacecraft will alter its orbit and take a nosedive into the gas giant’s atmosphere, destroying itself in the process. It’s all to prevent any Earth microbes that may have hitched a ride on the craft from contaminating possible alien life living on one of Jupiter’s moons.

For years, scientists have looked to Jupiter’s moon, Europa, as one of the best candidates for extraterrestrial life in our own solar system. While Europa’s surface is covered in a layer of water ice, scientists believe that it could hide an underground ocean that could potentially provide shelter to other life forms, Erik Shilling writes for Atlas Obscura.

“Whether the Jovian moon has the raw materials and chemical energy in the right proportions to support biology is a topic of intense scientific interest,” according to a NASA statement. “The answer may hinge on whether Europa has environments where chemicals are matched in the right proportions to power biological processes. Life on Earth exploits such niches.”

If life does exist on Europa (most likely in the form of microbes), its foothold could be tenuous, much like it was on Earth billions of years ago. The moon is constantly bombarded with Jupiter's radiation, which means that any potential life might survive only in Europa’s depths, Nola Taylor Redd reports for Space.com. While researchers have yet to launch any spacecraft missions with the sole purpose of studying Europa, they fear that if Juno is left to orbit Jupiter after its mission, there is a chance it could crash on the moon and contaminate it with Earth-based life, similar to how invasive species swarm new ecosystems.

Though two years may seem like a short mission, considering it took Juno five to reach Jupiter, scientists are approaching the craft's fate with caution. While Juno is heavily armed with radiation shielding to protect its systems against Jupiter’s radiation, its proximity to the gas giant means it won’t hold out for long. During this second half of the mission, the spacecraft will be exposed to 80 percent of the radiation its designer planned for, meaning they will have only a short window of time to accomplish their goals before losing control of Juno completely, Rebecca Boyle reports for Popular Mechanics.

“Stray electrons will collide with its computers, corrupting its memory. Each electron collision will produce a shower of secondary particles, which will also collide with Juno and create more showers of even smaller particles, and so on,” Boyle writes. “Eventually, this constant bombardment will cause memory failure, computer errors and potential hardware problems that could not only jeopardize scientific research, but also cause Juno to spiral out of control.”

By sending Juno on a death spiral into Jupiter’s atmosphere before they lose control, NASA’s scientists are safeguarding any chance that Juno could crash on Europa and infect it with Earth-born microbes, just as they did with the Galileo spacecraft in 2003. If life does exist in some form on Europa, taking this precaution is the best way to prevent inadvertent alteration of an alien world before NASA can safely explore it.