On July 14, 2015, NASA’s New Horizons spacecraft flew past Pluto, revealing unprecedented close-up views of the complex icy world. The iconic mission is still returning data from the far reaches of the solar system, but a lack of funding now threatens to end the mission prematurely.

As NASA celebrates the 10th anniversary of the historic Pluto flyby, the space agency is also bracing for budget cuts that threaten the historic New Horizons probe. The White House’s budget proposal, released in May, reduces NASA’s upcoming budget by $6 billion compared to 2025. Under the proposed budget, NASA’s planetary science budget would drop from $2.7 billion to $1.9 billion. The severe drop in funding would kill dozens of active and planned missions, including New Horizons.

New Horizons launched on January 19, 2006, and traveled 9 billion miles in nine and a half years to become the first spacecraft to reach Pluto. Its journey through the harsh space environment wasn’t the only challenge; members of the space community advocated for nearly 20 years for the approval of the spacecraft, according to The Planetary Society. At the time, NASA missions to Pluto were deemed not worth the cost. As a result, New Horizons was nearly canceled on multiple occasions due to budgeting conflicts. In 2002, the White House tried to kill the mission after NASA had already started developing it, but a massive backlash forced Congress to step in and restore New Horizons’ funding.

Despite its rocky start, New Horizons is now hailed as one of the most successful planetary missions. Following its close encounter with Pluto, the mission revealed that the icy planet and its moons are far more complex than scientists had initially assumed. New Horizons imaged a giant, heart-shaped icy plain on Pluto, which may sit above a subsurface ocean. It also revealed cryovolcanoes, indicating a geologically active body and not a dead, frozen world. The mission also explored Pluto’s icy, chaotic moons, which rotate chaotically.

Beyond Pluto, New Horizons continues to explore the outer reaches of the solar system. The spacecraft is shedding light on the mysterious planets and smaller objects of the outer solar system. In January 2019, New Horizons conducted the most distant flyby of a Kuiper Belt object when it explored Arrokoth, a frozen relic in the icy region beyond Neptune. The double-lobed object serves as a relic from the early solar system. The successful Arrokoth flyby earned New Horizons a mission extension, allowing the spacecraft to continue exploring until it exits the Kuiper Belt in 2029.

“The New Horizons mission has a unique position in our solar system to answer important questions about our heliosphere and provide extraordinary opportunities for multidisciplinary science for NASA and the scientific community,” Nicola Fox, associate administrator for NASA’s Science Mission Directorate, said in a statement at the time.

New Horizons has enough fuel to carry out another flyby of a Kuiper Belt object, and mission teams are currently searching for its next possible target. If the current budget proposal is approved, New Horizons will be turned off long before its expiration date, which would cost us years of valuable data. After Voyager 1 and 2, the New Horizons spacecraft is the third most distant human-built object from Earth. It would take years for another spacecraft to reach that distance. “We’re the only spacecraft out there,” Alan Stern, principal investigator for New Horizons, told The Planetary Society. “There’s nothing else planned to come this way.”