European and Japanese spacecraft near Mercury after decade-long journey

Two European and Japanese spacecraft separated from their mother ship Thursday, beginning the final phase of their nearly decade-long journey to Mercury, the solar system's smallest and closest planet to the Sun. Controllers waited two anxious hours for radio confirmation of the maneuver. The BepiColombo mission, launched in 2018, will enter orbit around Mercury in November and split into two probes in December to map the planet from different altitudes. It has traveled over 10 billion kilometers, requiring nine planetary flybys to slow down enough for capture. Only NASA's Messenger spacecraft has previously explored Mercury, a world of extreme contrasts with temperatures exceeding 427 degrees Celsius and icy polar craters. Scientific observations begin next spring, studying the planet's magnetic field, dense interior, and surface geology.