Updated

An instrument aboard the international Cassini spacecraft is making measurements again after nine months offline.

NASA said Monday the plasma spectrometer, which measures the energy of electrons and protons, is back in business after engineers spent months troubleshooting the problem.

The instrument was turned off as a precaution last June after Cassini experienced fluctuating voltage. The spacecraft used its other instruments to study Saturn and its many moons even with the spectrometer out of service.

An investigation pointed to "tin whiskers" growing on electronic components as the culprit, causing a short. NASA says these tiny metal filaments can grow in space just like on Earth.

Launched in 1997, Cassini has been exploring the Saturnian system since 2008.

Last week, the pockmarked surface of Saturn's second-largest moon came into sharper focus in new images released by NASA.

The space agency on March 13 released the new views of the moon Rhea, which were captured by the international Cassini spacecraft during a recent flyby. One of its cameras spied two huge impact basins and other geologic features on Rhea's icy surface from 26,000 miles away last week.

Cassini, funded by NASA and the European and Italian space agencies, was launched in 1997. It reached Saturn in 2004 and has been studying the ringed planet and its numerous moons.