Slim spacecraft lands on moon, power struggles

Jaxa notes lander’s solar panels misalignment, despite flawless descent.

Japan’s aspirations to be the fifth nation to softly land a functional spacecraft on the moon faced setbacks on Friday as mission controllers revealed the probe’s inability to generate electricity after landing.

The Smart Lander for Investigating Moon (Slim) was testing novel technologies for precise landings. Despite an apparently flawless approach and descent, the mission encountered a glitch when the probe landed around 3 pm UK time.

While signals from Slim and a small rover released just before touchdown were received by the space agency, an issue with the lander’s solar panels meant it relied solely on existing battery power. Officials suggested that the solar panels might not have been correctly angled toward the sun.

Slim is currently relying solely on its battery, and our priority is transferring its data to Earth,” stated Hitoshi Kuninaka, head of the Japanese Aerospace Exploration Agency (Jaxa) Space Lab, during a press conference held two hours after the lander’s touchdown.

The lander’s battery is anticipated to deplete within a few hours, but there is a possibility of onboard electricity generation if the sun’s movement in the coming weeks illuminates the solar cells.

Although the space agency believes Slim executed a soft landing, confirming whether the lander touched down within 100 meters of its target site near the Shioli crater, just south of the lunar equator – a key mission objective – is expected to take a month or so.

Achieving the anticipated precision would signify a transition from an era of “landing where we can” to “landing where we want,” according to Jaxa. High-precision landings are deemed crucial for future moon exploration.

The severity of the solar panel issue remains unclear, but it represents a setback for Jaxa. In 2022, the agency abandoned its initial moon landing attempt when it lost contact with the Omotenashi lander. Furthermore, a private lunar mission from Tokyo-based company iSpace experienced a crash landing on the surface last year.

On Christmas Day, Slim entered lunar orbit, following a fuel-efficient, months-long route to the moon. Around 3 pm UK time on Friday, it initiated its “powered descent sequence,” utilizing AI-based image recognition to identify patterns of craters on the surface and pinpoint its landing site.

Initially, everything seemed to be progressing smoothly, with spacecraft data indicating a controlled descent and successful touchdown. However, officials were initially unable to confirm the lander’s status upon reaching the lunar surface.

Moon missions are experiencing a resurgence in interest from major space agencies, driven by plans to return humans to the moon and exploit its resources. Despite successful soft landings by the Soviet Union and the US in the 1960s, there was a hiatus until 2013 when China’s Chang’e 3 achieved a soft landing. In 2023, India joined the elite club as the fourth nation with its Chandrayaan-3 lander.

Moon landings pose significant challenges. Recently, the private US Peregrine moon lander experienced a fuel leak and burned up over the south Pacific Ocean after launch. Last year, Russia’s Luna 25 spacecraft crash-landed on the moon, almost six decades after the Soviet Union’s Luna 9 achieved the first soft touchdown on lunar soil.

Shortly before landing, Slim deployed two palm-sized lunar excursion vehicles (Levs). The first, Lev-1, was designed to hop around, measure data with onboard instruments, and transmit signals to Earth. The second, a ball-shaped mini-rover developed in collaboration with Takara Tomy, used shape-changing technology to open up, revealing two cameras, with the hemispheres transforming into wheels.

While any scientific data from the mission is considered a bonus, one hope is for an onboard camera to study exposed mantle material at the landing site, potentially supporting the theory of the moon’s formation in a giant impact with Earth.

Katherine Joy, a professor in earth sciences at the University of Manchester, noted that Slim’s ability to send and receive signals suggests Japan is now the fifth country to achieve a soft landing on the moon. Despite this positive news, concerns arise as the solar panels are not charging up as planned, leaving the impact on mission longevity and scientific goals uncertain in the coming hours to days.