Japan has joined the United States, the former Soviet Union, China, and India to land a space probe on the moon’s surface. The country is now the fifth country in the world to ever soft land on the moon. Japan has been trying to attain such a milestone for a while now. However, the country has not succeeded until its most recent attempt when it landed SLIM spacecraft on the moon.
JAXA used precision technology to land closer to its targeted site than any mission before. Even though the spacecraft survived on the moon for just a few hours before power failure, JAXA now officially the fifth country to ever reach the moon.
Telemetry revealed that the Smart Lander for Investigating Moon, or SLIM spacecraft successfully landed in its targeted area near Shioli crater, south of the lunar equator early Saturday morning, about four months after launch from the Tanegashima Space Centre, off the south coast of Japan.
“SLIM has made it to the Moon’s surface. It has been communicating with our ground station and responding to commands from Earth accurately,” Hitoshi Kuninaka, vice president of Kanegawa-based Japan Aerospace Exploration Agency (JAXA), told a press conference after the landing was completed.
“However, it seems that the solar cells are not generating electricity at this point, and the spacecraft is operating solely on its battery,” Kuninaka said. “The battery will last several more hours — those hours will be the remaining life of SLIM.” He noted that the agency would continue monitoring the lander, as there was still a chance the panels would start working.
The successful soft landing took place around two weeks after the Peregrine US spacecraft was launched to the moon. However, the commercial US moon lander suffered a propellant problem as was safely crashed over the Pacific on Jan. 18.
The Innovative Technology of SLIM Spacecraft
Kuninaka revealed that the SLIM spacecraft has successfully accomplished its primary goal of soft landing on the moon with an accuracy of 100 meters of the targeted landing site. This landing is indeed a giant leap for Japan as previous missions crashed a few dozen kilometers from the planned landing site.
SLIM spacecraft landed on the moon with vision-based navigation technology. JAXA intended to use this technology to capture the image of the surface as it flew over the lunar surface. The technology also helps the spacecraft to locate itself quickly by matching the images with onboard maps.
Currently, scientists struggle to say if the SLIM spacecraft actually landed in the planned two-step manner using its five legs. Further investigations will determine if the car-sized, 200-kilogram spacecraft succeeded in this area.
Unlike past lunar landers that used four legs to reach a relatively flat surface, the SLIM spacecraft was to hit a 15-degree slope outside the Shioli crater first with one of its legs at the back, before stabilizing its entire body on the four front legs.
Why the SLIM Spacecraft’s Battery Failed After successful soft landing
Japanese scientists suggest that the SLIM spacecraft might have rolled during its soft landing, thereby preventing the craft’s solar cells from facing the Sun. Kuninaka noted that there is not enough data to determine the actual posture of the SLIM spacecraft. But if some sunlight could get to the moon lander it will restore its battery and continue its operation on the moon.
Hence, for the lander to come back to life, solar rays from the sun have to hit its panels. Kuninaka also said that an additional two small robots were to eject from SLIM before touchdown.
These robots were to take images of the lander and return them to Earth. However, the team behind the SLIM spacecraft could not tell if they were safely deployed.
If JAXA scientists bring SLIM back to life, they will use a specialized camera, which is the only scientific instrument onboard to search for a mineral known as olivine in the Moon’s mantle.
“If we can detect the olivine’s components and compare it with its counterpart on Earth, it may offer new evidence to support the theory that the Moon was part of Earth a long time ago,” says Shinichiro Sakai, the mission’s project manager at JAXA.
The onboard camera would also help the team to verify the origin of Apollo 16 Moon samples. Keep in mind that SLIM’s landing site is about 250 kilometers east of Apollo 16’s 1972 landing site and to the west of an ancient lunar sea called Mare Nectaris.
“In Apollo 16 samples, we found exotic basalts which were most likely ejected from Mare Nectaris,” says Clive Neal, a planetary geologist at the University of Notre Dame, Indiana. By helping confirm the source, SLIM could tell scientists a lot about impact dynamics and the chemistry of the ancient sea. “It would show that smaller missions can still be very productive and do important science,” Neal says.
Sakai and his colleague are hoping that SLIM spacecraft’s pinpoint landing technology would enable Japan to support the US Artemis Program which hopes to return humans to the moon in September 2026.
“This technology can be applied to many missions and may constitute a Japanese contribution to international cooperation,” says Sakai.
The entire world is really proud of JAXA for making Asia proud with its most recent SLIM spacecraft’s soft landing on the moon.