Just before the spacecraft Juno finishes a five-year trip to Jupiter on Monday, NASA has decided to extend the missions of nine older robotic explorers that have lived beyond original expectations.

The agency announced the decision on Friday, saying the nine are still producing bounties of observations for scientists.

Most of the extensions were expected. The New Horizons spacecraft, which flew past Pluto last year, had already been steered toward a new target, known as 2014 MU69, one of the small icy objects in the ring of debris beyond Neptune.

But one of NASA’s decisions, about the Dawn spacecraft orbiting Ceres, the dwarf planet in the asteroid belt, was somewhat of a surprise — as well as a disappointment to some working on the mission.