SLIM Lunar Lander Makes Japan Fifth Nation on Moon
Credit: JAXA 
The Japan Aerospace Exploration Agency’s SLIM lunar lander successfully touched down on the near side of the Moon on Jan. 19, 2024. The success makes Japan the fifth country to perform a soft lunar landing. The Smart Lander for Investigating Moon spacecraft deployed two small rovers onto the Moon’s surface. SLIM brings a new aspect to lunar landings because of its ability for precision landings on sloped surfaces.
SLIM touched down in the Mare Nectaris next to the Shioli crater, south of the Sea of Tranquility where humans first walked on the Moon. According to SLIM project manager Sakai Shinichiro, JAXA developed the spacecraft to land within 100 meters of a target, the highest accuracy ever achieved by a lunar landing mission. With this landing, lunar missions moved “from an era of landing where we can to an era of landing where we want.”
Solar Panels Not Working
Shortly after the landing, JAXA announced that SLIM’s solar panels were not working and that the spacecraft is running on battery power, meaning it has a limited lifespan. However, the agency believes most of SLIM’s equipment is operating successfully, as it is receiving temperature and pressure data. The battery is expected to only last for a matter of hours.
The spacecraft used a two-stage landing process for sloped surfaces, first tilting to touch down on its main landing gear, and then tipping forward to touch the ground with the rest of the spacecraft. JAXA referred to this descent sequence from 15km over the lunar surface as its “20 minutes of terror.”
The SLIM lunar lander launched on Sept. 6, 2023, and passed by the Moon in October. It continued on a swing orbit beyond the Moon to save fuel and re-entered lunar orbit on Christmas.
Two Landers Coordinate Communication
Just before SLIM landed, it released two Lunar Excursion Vehicles: LEV-1 and 2, to demonstrate different movement technologies. LEV-1 (2.1 kg) moves with a hopping motion and can communicate directly to Earth. LEV-2 (0.25 kg) is a ball-shaped, wheeled rover. It sends data back to LEV-1, which then sends it to Earth.
For more information on lunar activity and payloads, read The Space Report’s Q4 edition.
