Complex sentence: It was determined to be possible to reactivate the spacecraft in 2014, when it again made a close approach to Earth, and scientists discussed reusing the probe to observe more comets in 2017 or 2018.
Split into simpler sentences: It was determined to be possible to reactivate the spacecraft in 2014, when it again made a close approach to Earth. Scientists attempted to reuse the probe to observe more comets in 2017 or 2018.