— Ch. 1 · The First Touchdown On The Far Side —
Chang'e 4.
~4 min read · Ch. 1 of 5
At 02:26 UTC on the 3rd of January 2019, a robotic lander touched down inside Von Kármán crater. This moment marked the first time any spacecraft had ever landed on the far side of the Moon. Direct radio communication with Earth is impossible from that location because the Moon itself blocks all signals. Engineers had to solve this problem years before the landing attempt began. They launched a relay satellite named Queqiao in May 2018 to orbit behind the Moon at the L2 point. This satellite acts as a bridge between the distant rover and mission control on Earth. The Chang'e 4 mission was originally built as a backup for the earlier Chang'e 3 mission. It became available after Chang'e 3 successfully landed in 2013. Chinese engineers modified the design to handle the rough terrain found on the lunar far side.
Relay Satellites And Microsatellites
Queqiao carries a large antenna designed to receive X band signals from the lander. It relays those messages back to Earth using S band frequencies. The satellite took twenty-four days to reach its final halo orbit around the Earth-Moon L2 point. Two smaller microsatellites named Longjiang-1 and Longjiang-2 traveled alongside it during launch. Both were developed by Harbin Institute of Technology in China. Longjiang-1 failed to enter lunar orbit but Longjiang-2 succeeded. Longjiang-2 operated until the 31st of July 2019 when it crashed into Van Gent crater. That impact created a small four by five meter crater on the surface. These tiny satellites observed the sky at very low frequencies ranging from one to thirty megahertz. No observations in this frequency range have been done from Earth orbit due to interference from the ionosphere. This data offers potential breakthroughs in understanding energetic phenomena from celestial sources.