The Smart Lander for Investigating Moon (SLIM) of Japan became the fifth spacecraft to achieve a soft landing on the moon after it successfully touched down near the Shioli crater on January 19, 2024. But the spacecraft mission is facing a big challenge with its power generation as the lander's solar panels are playing up.
SLIM is an acronym for a robotic spacecraft designed to further develop new technologies for precise and safe lunar landing and to conduct scientific investigations of the lunar surface. The final version of the lander carried with it an infrared camera, a laser altimeter, while two small rovers were released shortly before touchdown.
The mission is to prove the ability to touch down within 100 meters of a designated target location, where future exploration would focus on certain sites of interest on the moon.
The lander was launched on September 14, 2023, from the Tanegashima Space Center in Japan aboard an H-IIA rocket. It used gravity assists from Earth and the moon to take it there on a parcels-saving, months-long route. On 25th December 2023, it was inserted into the lunar orbit and thereafter initiated powered descent on 19th January 2024 at about 3 p.m. UK time.
The last moment before touching the lunar surface, an onboard computer gently adjusted its direction with the help of image recognition based on AI – this computer identified the craters and other features on the surface and adjusted its trajectory accordingly to ensure a controlled landing.
SLIM also communicated with a relay satellite called Okina, which was launched together with SLIM into moon orbit to relay data and commands between the lander and the Earth.
According to the Japan Aerospace Exploration Agency (JAXA), the lander touched down correctly on the surface at about 3.20pm UK time, and signals were returned confirming it was operational.
However, not long after officials of JAXA said that there was a problem that had happened to the lander's solar panels which could not produce electricity. Meaning that this time being, the lander is operating only under its battery for some time given that it holds up for a specific capacity and then runs out of power.
JAXA vice president Hitoshi Kuninaka told a news conference that at that point the cause of the solar panel trouble is not known yet, but possibility they have not been angled correctly toward the sun, or possibly were damaged during the landing.
He said that JAXA is trying the priority transfer of lander data to Earth, such as images, telemetry, and landing accuracy. He added that JAXA is trying to save the mission, changing the attitude of the lander and also switching off heaters not required.
Kuninaka said JAXA believes SLIM achieved a soft landing, but it will take about a month to confirm whether the lander touched down within 100 meters of its target site — a major goal of the mission. He said the initial data suggests the lander had performed well during descent, and that new technologies for pinpoint landing worked as expected.
He also said that JAXA is receiving signals from the two rovers which were released by the lander and their status and location have not yet known. The rovers, christened as Tama and Koma, each weigh about 1.5 kilograms, around the size of a shoebox.
They carry cameras, thermometers and accelerometers and instead of walking - hop across the lunar surface to explore the surroundings of the lander.
Japan's second mission to land on the moon, SLIM seeks a pinpoint landing unlike its predecessor -- the Omotenashi lander which was launched 2022 as a secondary payload of a NASA's mission but failed to get to lunar orbit after communication hitch.
Japan also plans to send another lunar lander, SLIM-2 in the year 2026 which will carry a larger rover and a drill for collecting samples from the moon.
The SLIM mission is part of the ambitious plans of Japan for integration with global exploration of moon, and eventually also sending humans there for research work. It is also a partner of the NASA-led Artemis program, seeking returning astronauts to the moon by the end of the decade, and set up a sustainable presence there. As part of its contribution to the Gateway, a lunar outpost that will serve as a staging point for missions to the moon and beyond, Japan will supply hardware and expertise.
The moon is a viable target for scientific exploration and for commercial exploitation as it can contain much information about the origin of solar system, its evolutionary history and reservoirs of potential water and minerals.
Landing on the moon, however, is a tricky and perilous feat as the lunar environment is hostile and unpredictable while its surface is rugged and uneven. Before Japan, only four countries - the US, the Soviet Union, China and India - have successfully landed in working spacecraft on the moon.
The future SLIM mission is an excellent effort for Japan to show its technological capability and the readiness to work upon lunar exploration. But, at the same time, as each day passes nears the line of criticality for this mission because the power supply of the lander still remains unassured and therefore threatens to create a hindrance in reaching the scientific objectives of this mission.
JAXA officials and engineers are racing against time to save the mission, as well as salvage whatever data and images which the lander and the rovers can send back before they go silent. –(IVNTV)