Japan’s hopes of becoming the fifth country to soft-land a working spacecraft on the moon hit a snag on Friday after mission controllers said the probe failed to generate electricity after landing.
The Smart Lander for Investigating Moon (Smart) was testing new technologies for precision landings, but after a seemingly flawless approach and descent, the mission hit a snag when the probe shortly after 3pm UK time landed.
Although the space agency received signals from Slim and a tiny rover it released moments before landing, a problem with the lander’s solar panels meant it ran purely on existing battery power. It was possible that the lander’s solar panels were not facing the sun correctly, officials said.
“Slim is now only running on its battery, and we are prioritizing the transfer of its data to Earth,” Hitoshi Kuninaka, the head of the Japanese Aerospace Exploration Agency’s (Jaxa) space laboratory, told reporters during a press conference two hours. after the lander has landed.
The lander’s battery is expected to drain in a matter of hours, but it may be possible to generate electricity on board if the sun’s movement sheds light on the solar cells in the coming weeks.
The space agency believes Slim achieved a soft landing, but it is expected to take a month or so to confirm whether the lander landed within 100 meters of its target location near the Shioli Crater, just south of the lunar equator has – a major goal for the mission.
If the probe achieves the expected accuracy, it would mark a shift from an era of “land where we can” to “land where we want,” Jaxa said. Such high-precision landings will be crucial for the future exploration of the moon.
It is unclear how serious the solar panel problem is, but the failure is a disappointment for Jaxa, which abandoned its first attempt to land on the moon in 2022 when it lost contact with the Omotenashi lander. Last year, a private lunar mission from the Tokyo-based company iSpace crashed down on the surface.
Slim soared into lunar orbit on Christmas Day after taking a fuel-efficient, months-long route to the moon. At around 3pm on Friday UK time, it began its “powered descent sequence”, using AI-based image recognition to detect patterns of craters on the surface and locate its landing site.
Everything appeared to be going smoothly, with data from the spacecraft suggesting a steady descent and landing, but officials were initially unable to confirm the lander’s status when it reached the surface.
Moon missions are back in favor with major space agencies amid plans to return humans to the surface and exploit water and other resources found there. But while the Soviet Union and the US both nailed soft landings in the 1960s, the Soviet Luna 24 mission in 1976 was the last to do so until 2013, when China’s Chang’e 3 touched down. India became the fourth nation to join the elite club in 2023 with its Chandrayaan-3 lander.
Landing on the moon is far from straight. On Thursday, the private American Peregrine lunar lander fell back to Earth and burned up over the South Pacific after developing a fuel leak shortly after launch. Last year, Russia’s Luna 25 spacecraft crashed on the moon nearly 60 years after the Soviet Union’s Luna 9 made the first soft landing on lunar soil.
Moments before landing, Slim released two palm-sized lunar excursion vehicles, or Levs. The first, Lev-1, is designed to bounce around and take measurements with an onboard thermometer, radiation monitor and tilt sensor, and send signals back to Earth. The second, a ball-shaped mini-rover designed with Takara Tomy, the toy firm behind Transformers, uses the same shape-shifting technology to pop open, revealing two cameras and turning the two hemispheres into wheels.
For mission controllers, any science that can carry out the mission would be a bonus. One hope is for an onboard camera to study exposed mantle material at the landing site, to see if it supports the theory that the moon formed in a giant impact with Earth.
Katherine Joy, a professor of earth sciences at the University of Manchester, who studied lunar samples from the Apollo program, said the fact that Slim was sending and receiving signals implied that Japan was now the fifth country to make a soft landing on the moon achieved. “That’s wonderful news,” she said. “However, the solar panels are not charging as planned. What this means for the longevity of the mission or achieving the science goals will be seen over the next few hours to days.”
