Japan lands uncrewed spacecraft on the moon, but with complications

Japan became the fifth country to put a spacecraft on the moon but the probe was not generating solar power, its space agency said Saturday, during a mission to prove a "precision" landing technology and revitalize a space program that has suffered setbacks.

The Japan Aerospace Exploration Agency (JAXA) said its Smart Lander for Investigating Moon (SLIM) landed the moon's surface at around 12:20 a.m. local time and re-established communication with Earth, but its solar panels were not able to generate electricity, possibly because they are angled wrong.

"SLIM is now operating only on its battery, and we are prioritizing the transfer of its data onto Earth," Hitoshi Kuninaka, the head of JAXA's space lab, told a news conference.

Dubbed the "moon sniper," SLIM attempted to land within 100 metres (328 feet) of its target, versus the conventional accuracy of several kilometres, a technology JAXA says will become a powerful tool in future exploration of hilly moon poles seen as a potential source of oxygen, fuel and water.

It will take up to a month to verify whether SLIM had achieved the high-precision goals, JAXA has said.

JAXA has twice landed on small asteroids, but unlike with an asteroid landing, the moon's gravity means the lander cannot pull up for another try, its scientists said. Three lunar missions by Japanese startup ispace, Russia's space agency and American company Astrobotic have failed in the past year.

Only four countries — the former Soviet Union, the United States, China and India — and no private company have achieved a soft landing on the moon's surface.

Accurate landing sought

The vehicle that measures 2.4 metres by 1.7 metres by 2.7 metres includes two main engines and 12 thrusters, surrounded by solar cells, antennas, radar and cameras. Keeping it lightweight was another objective of the project, as Japan aims to carry out more frequent missions in the future by reducing launch costs. SLIM weighed 700 kilograms at launch.

As the probe descended onto the surface, it was designed to recognize where it was flying by matching its camera's images with existing satellite photos of the moon. This "vision-based navigation" enables a precise touchdown, JAXA has said.

Shock absorbers make contact with the lunar surface in what JAXA calls new "two-step landing" method — the rear parts touch the ground first, then the entire body gently collapses forward and stabilizes.

On landing, SLIM successfully deployed two mini-probes — a hopping vehicle as big as a microwave oven and a baseball-sized wheeled rover — that would have taken pictures of the spacecraft, JAXA said. Tech giant Sony Group, toymaker Tomy and several Japanese universities jointly developed the robots.

While most previous probes have used landing zones about 10 kilometres wide, SLIM was aiming at a target of just 100 metres.

Disappointments last year for Japan

SLIM was launched on a Mitsubishi Heavy H2A rocket in September. It initially orbited Earth and entered lunar orbit on Dec. 25.

Japan is increasingly looking to play a bigger role in space, partnering with ally the United States to counter China. Japan is also home to several private-sector space startups and the JAXA aims to send an astronaut to the moon as part of NASA's Artemis program in the next few years.

But the Japanese space agency has recently faced multiple setbacks in rocket development, including the launch failure in March of its new flagship rocket H3 that was meant to match cost-competitiveness against commercial rocket providers like SpaceX.

The failure caused widespread delays in Japan's space missions, including SLIM and a joint lunar exploration with India, which in August made a historic touchdown on the moon's south pole with its Chandrayaan-3 probe.

The closely watched mission came only 10 days after a moon mission by a U.S. private company failed when the spacecraft developed a fuel leak hours after the launch. That Peregrine lunar lander contained the remains of a number of celebrities, as well as deceased space enthusiasts, including a Vancouver woman.