The Japan Aerospace Exploration Agency (Jaxa) said the Smart Lander for Investigating Moon (SLIM) reached 15km above the moon’s surface, where it will start an autonomous 20-minute descent from midnight tomorrow.
Dubbed the “moon sniper”, SLIM is attempting to land within 100m of its target, versus the conventional accuracy of several kilometres.
Jaxa says this landing technology will become a powerful tool in future exploration of hilly moon poles seen as a potential source of oxygen, fuel and water – factors necessary to sustain life.
Jaxa will broadcast the touchdown on its YouTube channel, but has said it will take up to a month to verify whether SLIM had achieved the high-precision goals.
Japan is increasingly looking to play a bigger role in space, partnering with ally the US to counter China.
Japan is also home to several private sector space start-ups and Jaxa aims to send an astronaut to the moon as part of Nasa’s Artemis programme 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.
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.
Jaxa has twice landed on small asteroids, but a moon landing is much more difficult due to its gravity.
Three lunar missions by Japanese start-up ispace, Russia’s space agency and American company Astrobotic have failed in the past year.
Only four nations – the former Soviet Union, the US, China and India – and no private company have achieved a soft landing on the moon’s surface.
SLIM’s successful touchdown and demonstration of the precision landing “will help Japan to keep its technology advanced at a very high level in the world”, Ritsumeikan University professor Kazuto Saiki said.
Saiki developed SLIM’s near-infrared camera that will analyse moon rocks after the touchdown.
“Mistakes happen, but Japan is a very experienced space power – it’s conducted very complicated space operations for many years,” said Bleddyn Bowen, a University of Leicester associate professor specialising in space policy.
“Not as big as the US or the Soviet Union of old or China today in terms of scale, but in terms of capability and niche advanced technologies, Japan has always been there.”
SLIM’s precision landing “won’t be a game changer”, but the demonstration of it and the lightweight probe manufacturing Japan has pursued might open up moonshots to space organisations worldwide by reducing the cost of each mission, Bowen added.
On landing, SLIM will also deploy two mini probes – a hopping vehicle as big as a microwave oven and a baseball-sized wheeled rover – that will take pictures of the spacecraft.
Tech giant Sony Group, toymaker Tomy and several Japanese universities jointly developed the robots.