Two Mercury-bound spacecraft left their mother ship behind on Thursday and headed down the home stretch of their nearly decade-long voyage to the solar system's smallest and closest-to-the-sun planet.
The linked European and Japanese spacecraft separated as planned from their cruiser, but controllers had to wait two anxious hours to receive confirmation via radio signals. The crucial operation was broadcast from the European Space Agency's control center in Germany, more than 124 million miles (200 million kilometers) away.
