The far side of the moon has no direct communications link with Earth, so the landing procedure was largely autonomous, although engineers could still monitor the situation and send instructions using the Queqiao-2 relay satellite, which launched in March this year and is currently in lunar orbit. Once the lander and its attached ascent module had separated from the orbital part of the spacecraft, they began a controlled descent with their engines, using an obstacle avoidance system and camera to detect boulders and rocks and select a smooth landing area. At around 100 metres above the lunar surface, a laser scanner selected a final site before the engines switched off and the vehicle made a cushioned touchdown.