Japan's triumphant Moon touchdown stands as the epitome of precision, setting a new standard for achievement in space exploration.
Artist's impression of the SLIM spacecraft coming in for landing on the Moon.
Touching down just 100 meters from its intended
destination, the spacecraft blazes a trail with its revolutionary image-based
automatic navigation. However, the mission now teeters on the brink of an
abrupt conclusion.
In a groundbreaking achievement, Japan has secured its
position as the fifth nation globally to softly land a spacecraft on the lunar
surface. Employing sophisticated technology, the mission showcased
unprecedented precision, allowing the spacecraft to touch down with remarkable
proximity to its targeted landing site—a feat unparalleled in previous lunar
missions. However, the triumph might be short-lived, as the spacecraft faced
potential jeopardy due to a power failure, potentially limiting its survival on
the moon's surface to a mere few hours.
Telemetry data revealed that the Smart Lander for
Investigating Moon, acronymically known as SLIM, successfully made its descent
within the designated area near the Shioli crater, positioned south of the lunar
equator. This achievement unfolded early on a Saturday morning, precisely four
months after the spacecraft initiated its journey from the Tanegashima Space
Centre, located off the southern coast of Japan.
Hitoshi Kuninaka, the Vice President of the Kanegawa-based
Japan Aerospace Exploration Agency (JAXA), conveyed the success at a press
conference following the completion of the landing. "SLIM has gracefully
reached the Moon's surface, maintaining seamless communication with our ground
station and obediently responding to commands from Earth," stated
Kuninaka. However, he expressed concern over the current inability of the solar
cells to generate electricity, leaving the spacecraft reliant solely on its
battery. "The battery's lifespan is now a matter of several more
hours—those precious hours constitute the remaining existence of SLIM," he
elaborated, emphasizing the agency's continued vigilance in the hope that the
panels might eventually resume functionality.
This achievement comes on the heels of a recent setback
where a commercial US spacecraft, launched for the Moon, encountered propellant
issues, jeopardizing its planned landing. Additionally, almost a year ago, a
Japanese commercial lander faced failure in its lunar endeavor, highlighting
the inherent challenges of lunar landings, particularly for commercial
enterprises.
Namrata Goswami, a space policy researcher at Arizona State
University, deemed this successful landing a "significant triumph for
Asia." Within the last decade, only China, India, and Japan have managed
to land spacecraft on the Moon, with India achieving success in August 2023.
Highlighting the innovative technology at play, Kuninaka
suggested that SLIM likely achieved its primary objective—landing on the Moon
with unparalleled accuracy, a substantial leap from the imprecise ranges of
previous missions. Equipped with vision-based navigation technology, SLIM aimed
to capture images of the lunar surface during its flight, swiftly locating
itself by matching these images with onboard maps.
The intricacies of SLIM's touch-down remain uncertain, as
the spacecraft was designed to execute a unique two-step landing process with
its five legs. Unlike previous landers that utilized four legs to reach a
relatively flat surface simultaneously, SLIM targeted a 15-degree slope outside the Shioli crater initially with one rear leg, then tipping forward to stabilize on
the four front legs. Observers speculate that SLIM might have experienced a
roll during touch-down, preventing its solar cells from facing the Sun.
Although data on the probe's posture and orientation are insufficient, a
glimmer of hope exists if sunlight manages to reach the solar cells.
Adding to the mission's complexity, two small robots were
intended to deploy from SLIM before landing to capture images of the lunar
surface. However, it remains unclear if these robots successfully executed
their deployment.
Should SLIM revive, scientists plan to utilize a
specialized camera—the sole scientific instrument onboard—to search for a
mineral called olivine in the Moon's mantle. Shinichiro Sakai, the mission's
project manager at JAXA, explained that detecting olivine's components and
comparing them with Earth's counterpart could provide new evidence supporting
the theory that the Moon was once part of Earth.
Furthermore, the camera could assist in confirming the
origin of the Apollo 16 Moon samples. Positioned about 250 kilometers east of
Apollo 16's 1972 landing site and to the west of the ancient lunar sea Mare
Nectaris, SLIM's findings could shed light on impact dynamics and the chemistry
of the ancient sea. Clive Neal, a planetary geologist at the University of
Notre Dame, sees the potential for smaller missions to yield significant
scientific contributions, showcasing their productivity and importance.
Project manager Sakai and his team envisioned SLIM's
pinpoint landing technology propelling Japan ahead in the US-led Artemis
Program, aiming to return humans to the Moon within three years. He expressed
optimism that this technology could serve as a valuable Japanese contribution
to international cooperation.
While Japan's successful lunar landing marks a significant
accomplishment for Asia, it also intensifies the competition among spacefaring
nations in the region. With both India and Japan mastering the technology for
soft lunar landings, their planned joint mission, the Lunar Polar Exploration
Mission (LUPEX), could pose a formidable challenge to China's Chang'e-7
mission, set to land in the lunar south pole region in 2026 in search of frozen
water.
The Moon is experiencing a surge in visitors in recent
months, with SLIM being the second lunar landing attempt this year, following
the unfortunate fate of the US Peregrine spacecraft. In the upcoming month, US
company Intuitive Machines aims to continue the challenge, aspiring to become
the first commercial company to land a spacecraft on the Moon. Additionally,
later this year, China plans to launch its Chang'e-6 mission to retrieve
samples from the far side of the Moon, adding to the increasing lunar exploration
endeavors.