European and Japanese spacecraft near Mercury after nearly 10-year journey

Two European and Japanese spacecraft separated from their mother ship Thursday, beginning the final leg of their nearly decade-long journey to Mercury, the solar system's smallest and sun-closest planet. Controllers waited anxiously for two hours to confirm the separation via radio signals from over 200 million kilometers away. The BepiColombo mission, launched in 2018, will enter Mercury's orbit in November and split into two orbiters in December to study the planet from different altitudes. Only NASA's Messenger spacecraft has previously explored Mercury, which has extreme temperatures exceeding 427 degrees Celsius at its surface while its poles hold ice. The mission has traveled over 10 billion kilometers using nine planetary flybys to slow down, with scientific observations beginning next spring.