Japan's space agency encountered a setback with its Smart Lander for Investigating the Moon, also known as SLIM, when the lander failed to respond to a signal sent Monday evening.
The resilient lunar lander has defied expectations by surviving multiple long, cold lunar nights that typically doom other landers. However, the Japan Aerospace Exploration Agency (JAXA) indicated on SLIM’s official X account that the harsh and relentless conditions “might finally be showing” their effects.
SLIM’s journey has been one of remarkable tenacity. During its landing on Jan. 20, one of its two engine nozzles fell off and it landed upside down, with most solar cells facing away from the sun.
Despite the initial setback, JAXA managed to retrieve some data and a partial image, hoping that as the angle of the sun changed, enough power would be generated for the probe to awaken.
Against all odds, in late January, SLIM proceeded to surprise even its own engineers when it regained power and resumed operations. By the end of its first sunlit period, SLIM sent back a panorama of its landing site, as well as other data.
The lander continued to surprise by stirring back to life and reestablishing contact in February, March, and April, surviving consecutive lunar nights.
However, the lander's story may be about to come to a close.
JAXA attempted to send signals to it on Friday and Saturday, expecting sufficient solar energy, but was met with no response.
After a final attempt on Monday, JAXA announced on SLIM’s official X account that operations for the month had to come to an end.
SLIM is part of a new generation of low-cost lunar landers that rely solely on solar cells instead of radioisotope heater units. However, the trade-off for this is a shorter operational lifespan — such landers are not designed to survive the frigid cold of a lunar night, which extend up to 14 days, with temperatures dropping to minus 170 degrees Celsius.
Yet, hope remains for the moon lander.
JAXA plans to try again next month when the sun returns to the landing site, hoping the lander will reboot with sufficient solar power.
Photos taken by SLIM in its relatively brief lifespan have already contributed to understanding about the moon’s surface. On Monday, a team of researchers from Ritsumeikan University and the University of Aizu, among others, revealed at a Japan Geoscience Union meeting in Chiba Prefecture that SLIM’s images show the existence of the mineral olivine.
Olivine is the main component of the Earth's upper mantle and is believed to be that of the lunar mantle, which makes up 90% of the moon's mass.
Comparing olivine from the moon and the Earth may support the widely accepted theory that the moon had formed from the debris of a collision between the Earth and another celestial body, and have significant implications on our understanding of the moon’s origins.
“Further examination is required to determine whether the moon's olivine actually originated from the Earth’s mantle,” said Kazuto Saiki, a professor at Ritsumeikan University.
“But the presence of olivine has been confirmed,” he noted.
University of Aizu's professor Makiko Otake added that the data collected has been long-awaited, and provides extremely hopeful results. She expressed determination that the data might shed more light on the moon's origin through further analysis.
As researchers and engineers hold their breath for next month's reactivation attempt, JAXA praises the lander’s efforts thus far.
“SLIM has already transmitted far more valuable data than we had ever anticipated prior to launch,” the agency said on X.
“We will continue our recovery efforts to keep it active for as long as possible.”
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