Goodbye

S2, E14: A faint radio signal is picked up in Stardust Bay... coming from the direction of the Sun. Flying off to investigate, Eagle, Robyn and Raven trace the signal to Mercury instead. It seems to be coming from MESSENGER, a spacecraft that was sent to explore Mercury ages ago - but everyone had long presumed the probe to be destroyed. Is it still functioning? The racers carefully touch down on Mercury's shaded side - a tricky feat thanks to its proximity to the Sun during its broadly elliptical orbit. When they finally find MESSENGER, what's left of him is very weak, and there's nothing they can do to help. But MESSENGER says he's okay about that, and asks them to bring his final images and research back to Earth while he lives out his days on Mercury. The kids bid a sad farewell to the probe, who will always be remembered for his landmark discoveries.