Japanese “Moon Sniper” lands 55 meters from the lunar target

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Japan's space agency said Thursday that its robotic Moon Sniper rover landed 55 meters (165 feet) from its target on the lunar surface last week, calling it a “major achievement” despite problems during landing that put the mission in jeopardy.

Lunar Exploration Intelligent Lander, or SLIM, It reached the moon's surface just after 10:20 a.m. ET (12:20 a.m. Saturday JST) on January 19, according to data shared by the Japan Aerospace Exploration Agency.

During its landing, the spacecraft encountered “some kind of anomaly” at a distance of about 50 meters (165 feet) above the surface, officials at the Japan Aerospace Exploration Agency said in a press conference. As a result, thrust was lost from one of the main engines, forcing the spacecraft to land on its nose with its “main engine facing upward and in a nearly vertical position.”

Now, the spacecraft's solar panels face west instead of upward as intended, forcing them to operate on limited battery power.

Japan Aerospace Exploration Agency officials said the lander's battery has since been turned off to preserve the spacecraft's functionality. If Moon Sniper can survive the frigid temperatures of lunar night, the space agency hopes that light will reach the solar cells as the sun's angle on the moon changes, potentially restoring power generation and allowing operations to resume.

Despite these challenges, the agency hailed the moment as “an important milestone for future lunar and planetary exploration.” The SLIM explorer used new precision technology to demonstrate a “pointed” landing and successfully achieved its goals of landing within 100 meters of its target.

The agency said Thursday that it was able to communicate with SLIM after landing and released the first images transmitted by SLIM from the surface of the moon.

The lander used its multi-range camera to take 257 low-resolution images of the lunar surface, which were combined to show the SLIM's surrounding landscape. The mission team analyzed the mosaics and gave the rocks interesting nicknames that correspond with estimates of their size. If the lander is operated again, the team hopes to conduct further observations to identify SLIM's landing site, which is located on the slope of a crater in a lunar region called the Nectar Sea.

Aizu University assistant professor Chikatoshi Honda was involved in developing the camera after establishing the tools team in 2016.

“Given that exploration programs do not necessarily lead to data acquisition, we are pleased to see that SLIM has paid off and captured something tangible with the camera,” Honda said in a statement.

This landing made Japan the third country this century – and the fifth ever – to land on the moon.

The Japan Aerospace Exploration Agency said it was investigating the causes of the anomaly during landing and the loss of main engine function. Space agency officials added that they hope the technology developed at SLIM can be applied to future space missions.

Before landing, the SLIM mission achieved another milestone: the successful launch of two lunar rovers, LEV-1 and LEV-2. The LEV-1 rover moves using a hopping mechanism and is equipped with wide-angle visible light cameras, scientific equipment and antennas that allow it to communicate with Earth. LEV-2, also equipped with cameras, can change its shape to move across the lunar surface.

LEV-1 jumped across the lunar surface and communicated directly with ground stations on Earth using its antennas, including a test transmission of data from LEV-2, also known as SORA-Q. But no images were received from the rovers.

The LEV-1 rover has completed its initial objectives after landing, has exhausted its power and is currently in standby mode on the lunar surface, just like the SLIM lander. The mission team is still listening for signals from LEV-1, which will not be able to wake up until solar power is generated. The status of LEV-2 is currently unclear.

Together, LEV-1 and LEV-2 become Japan's first lunar exploration robots, according to Lunar Exploration Agency officials. LEV-1's ability to communicate directly with Earth is “the world's smallest and lightest case for transmitting live data from a distance of approximately 380,000 kilometers (236,121 miles),” according to the agency. The vehicle weighs only 4.6 lbs (2.1 kg).

“Furthermore, the achievement of LEV-1 jump movements on the lunar surface, inter-robot communication between LEV-1 and LEV-2, and fully autonomous operations represent a groundbreaking achievement,” said one of the researchers. Launching of JAXA. “It will be seen as a valuable technology demonstration for future lunar explorations, and the knowledge and experience gained will be applied in upcoming missions.”