The moon landing was a success, but the Japanese flight control was still in a grave mood. On Friday afternoon around 4:20 PM (Dutch time), the lunar lander SLIM (Smart Lander for Investigating Moon) landed in the Mare Nectaris (‘nectar sea’), not far from the lunar equator. Signals have been received, but the solar cells are not providing power, said Hitoshi Kuninaka, head of the research department at the JAXA space agency. The spacecraft may have tilted and they may be in the shadows. The battery only lasts a few hours, so SLIM is now dead.
“The minimum criterion for success was the moon landing,” Kuninaka said at a press conference, “so in that respect it is a success.” This makes Japan the fifth country to land on the moon, after the US, the Soviet Union, China and last summer India. It remains to be seen how much data can still be sent home.
Fallover landing
SLIM, also known as ‘moon sniper’, had to demonstrate quite a few new technologies. The main goal was to land with a precision of 100 meters, aided by a kind of facial recognition software that can recognize the craters and make adjustments. It appears that this has been successful, Kuninaka said, although this will only be known for certain after analyzing photos.
The topple landing is also unprecedented: the 2.7 meter high and 200 kilogram heavy spacecraft descended upright, braking with rocket motors, only to fall over at the last minute. This would make it more stable on the 15 degree slope. At the ends of its five legs are 3D-printed aluminum shock absorbers, which absorb the impact by crumpling.
There were also two autonomous lunar robots on board. LEV-(Lunar Excursion Vehicle)-1 can jump, has cameras on board, and can communicate independently with Earth, although it is not yet clear whether this has been successful. LEV-2, weighing 250 grams, has an expandable spherical shape the size of a baseball. The two halves function like wheels. LEV-2 was co-developed by toy manufacturer Takara Tomy, who also launched a toy variant.
Hope of revival
SLIM was launched on September 6, 2023, together with the X-ray telescope XRISM, and had completed a lunar journey of 110 days to save fuel. The lunar robot should have spent a ‘lunar day’, fourteen Earth days, conducting research on the moon. It was expected that the dark moon night with temperatures of -130 degrees would spell the end for the on-board electronics. Still, there is hope that the next lunar day the sun will strike the solar panels at a different angle and miraculously revive the lander.
After decades of dormancy, the moon is the subject of a new wave of robotic missions, including three successful Chinese Chang’e landers. In May, China plans to launch its Chang’e 6 mission to bring rock samples from the far side of the moon to Earth for the first time.
Space is hard
But with the meager Japanese success, the cliché remains ‘Space is hard‘ upright: in April 2023 the Japanese lunar lander Hakuto-R crashed, in August the Russian Luna 25 crashed, and earlier this month the American Peregrine moon mission also failed due to a fuel leak.
There is also disappointing space robot news from Mars: NASA reports loss of contact with Ingenuity, the highly successful Mars helicopter that performed 72 flights in the thin Martian atmosphere.