Japan on Saturday became the fifth country to land on the Moon, but its spacecraft ended up in an awkward position, with its engine nozzle pointed into space.
By design, the Japanese spacecraft, known as the Smart Lander for Investigating Moon, or SLIM, was supposed to land on its side, a strategy to avoid tipping over on the landing site’s sloping terrain.
But about 150 feet above the ground, one of SLIM’s two main engines appears to have failed, officials at JAXA, the Japanese space agency, said Thursday.
With the onboard computer trying to compensate for the sudden loss of half thrust, the spacecraft was still able to hit the ground at a modest vertical speed of about 3 miles per hour. But the SLIM’s horizontal speed and orientation on landing were outside what it was designed to handle.
As a result, the spaceship rolled over its head. She escaped the fate of some other recent robotic missions, which broke up on the moon, and her systems worked, communicating with Earth. But the solar panels ended up facing west, away from the morning lunar sun, and were unable to generate electricity. With the battery nearly depleted, mission controllers on Earth sent an order to shut down the spacecraft less than three hours after landing.
Despite the setback, the mission achieved its main objective: a soft landing on rough terrain on the Moon, less than 100 meters from a target landing site, much more precise than the uncertainty of the miles that most studies point to. landers.
“It successfully achieved the controlled landing,” Hitoshi Kuninaka, director general of JAXA’s Institute of Space and Astronautical Sciences, said in Japanese at a news conference. “We confirmed that the landing position was 55 meters from the initial target. So we concluded that we achieved the precise landing with an accuracy of 100 meters.”
During its brief operation, an instrument on the lander took low-resolution black-and-white images of the surrounding landscape. Members of the SLIM team put dog breed nicknames on rocks that caught their attention.
Two small rovers ejected from SLIM just before landing moved around the lunar surface and one of them took a photograph of the inverted lander.
JAXA officials remain optimistic that SLIM could revive in about a week, when, during the two-week lunar afternoon, the sun will shine from the west, illuminating the solar panels.
“We will try to establish communications as SLIM starts working automatically when power generation begins,” which could allow operations to resume, Shinichiro Sakai, SLIM project director, said during the news conference.
If SLIM comes back to life, the lander’s instrument will make detailed measurements of rock and soil composition.
Dr. Sakai said he had “mixed feelings” about the orientation in which the spacecraft ended up. “If the solar cells were upside down on the surface, there would be no chance of receiving sunlight, so I feel very relieved. It remained as it is,” he stated.
Dr. Sakai said photographs taken by SLIM during its descent, before and after its partial loss of thrust, indicate that one of the engine’s nozzles fell off. JAXA officials are investigating what went wrong.