by Japan became the fifth country in history to reach the Moon when its spacecraft landed on the lunar surface early Saturday, officials said.
But an issue with the power supply means the mission could be in jeopardy.
Officials also said they needed more time to analyze whether the spacecraft, which was not carrying astronauts, made a perfect landing – one of the mission’s priorities.
Hitoshi Kuninaka, head of the Institute for Space and Astronomical Science, said they believe rovers were launched and data was being transmitted back to Earth from the Smart Lander for Investigating Moon, or SLIM.
But he said the SLIM solar battery was not generating power and the spacecraft’s battery life would last only a few more hours. He said the priority now for the craft is to collect as much Moon data as possible on the remaining battery.
Japan follows the United States, the Soviet Union, China and India to reach the Moon.
Kuninaka said he believes Japan’s space program has achieved at least “minimal” success.
The SLIM mission
SLIM landed on the moon at around 12:20 a.m. Tokyo on Saturday (4.20 p.m. CET on Friday).
There was a tense wait for news after the Japanese space agency’s mission control initially said SLIM was on the moon’s surface, but was still “checking its status”.
No further details were given until a news conference nearly two hours later.
For the mission to be considered a complete success, space officials must confirm whether SLIM made a pinpoint landing. Kuninaka said that while more time is needed, he personally thinks it has been achieved, based on his observation of data showing the movement of the spacecraft until landing.
SLIM is a lightweight spacecraft, intended to reach a very small target, about the size of a passenger vehicle. It was using “pinpoint landing” technology that promises far more control than any previous lunar landing.
While most previous probes used landing zones around 10 km wide, SLIM aimed for a target of just 100 m.
The project was the result of two decades of work on precision technology by the Japan Aerospace Exploration Agency, or JAXA.
‘Check their status’
As the spacecraft descended, JAXA mission control said everything was going as planned and later said SLIM was on the lunar surface.
But there was no word on whether the landing was successful. Mission control kept repeating that it was “checking its status” and that more information would be given at the news conference.
SLIM, known as “the Sniper Moon,” began its descent at midnight on Saturday, and within 15 minutes it was down to about 10 km above the lunar surface, according to the JAXA space agency.
At an altitude of 5 km, the lander was in vertical descent mode, then at 50 m above the surface, SLIM was supposed to make a parallel movement to reach a safe landing site, JAXA said.
The main goal of the mission is to test new landing technology that would allow lunar missions to land “where we want, rather than where it’s easy to land,” JAXA said.
The spacecraft is designed to look for clues about the Moon’s origin, including analyzing minerals with a special camera.
The SLIM, equipped with an impact cushion, aimed to land near the Shioli crater, near a region covered in volcanic rock.
The close watch mission came just 10 days after a private US company’s Moon mission failed when the spacecraft developed a fuel leak hours after launch.
SLIM was launched on a Mitsubishi Heavy H2A rocket in September. It first orbited Earth and entered lunar orbit on December 25.
Japan hopes to regain confidence in its space technology after several failures.
A spacecraft designed by a Japanese company crashed during a lunar landing attempt in April, and a new flagship rocket failed its first launch in March.
JAXA has a track record of difficult offloads. Its Hayabusa2 spacecraft, launched in 2014, touched down twice on the 900-meter-long asteroid Ryugu, collecting samples that were sent back to Earth.
The Importance of the Moon
Experts say a successful SLIM pinpoint landing, especially on the Moon, would raise Japan’s profile in the global space technology race.
Takeshi Tsuchiya, a professor of aeronautics at the Graduate School of Engineering at the University of Tokyo, said confirming the accuracy of landing on a targeted area was important for the future of lunar exploration.
“It is necessary to show the world that Japan has the appropriate technology to be able to properly assert Japan’s position in lunar development,” he said.
The Moon is important for resource exploration, and it can also be used as a base to go to other planets, like Mars, he said.
SLIM is carrying two small autonomous probes – lunar excursion vehicles LEV-1 and LEV-2, which will be launched just before landing.
LEV-1, equipped with an antenna and camera, is tasked with recording the SLIM landing. LEV-2, a ball-shaped rover equipped with two cameras, is developed by JAXA together with Sony, toy maker Tomy and Doshisha University.
