Japan's lander mission to reach lunar orbit in three months

If everything proceeds according to the plan, SLIM, also known as Moon Sniper, will attempt to achieve Japan's first soft lunar landing in a few months.

SLIM, which stands for Smart Lander for Investigating Moon, represents a technology demonstrator mission to accomplish a precise landing on the lunar surface.

Japan’s spacecraft embarks on a long journey to reach lunar orbit 

SLIM is a compact and lightweight probe designed to achieve a precise landing at the designated location adjacent to the Shioli Crater near the "Sea of Nectar" on the moon's near side.

“Because the landing site is located near a crater, the surrounding area is sloped to approximately 15 degrees,” noted JAXA's press kit for SLIM. 

Despite this, the lander will attempt to land within 330 feet (100 meters) of this chosen spot. 

This landing, however, will take place after the next 3-4 years, most likely in January or early February 2024. This is due to the long and fuel-efficient route opted by JAXA to reach lunar orbit. 

How will it achieve pinpoint landing?

A soft landing on the moon, especially at a specific spot, is a complex and challenging task involving intricate engineering and careful planning. 

As a result, SLIM has been integrated with a number of advanced precision-based technologies, one of which is "vision-based navigation." 

This technology will guide the spacecraft to a precise landing while adjusting its trajectory in real time to avoid risks.

SLIM's onboard computer contains maps of the craters in the vicinity of the mission's landing site, which were previously documented by the JAXA's Kaguya and NASA's Lunar Reconnaissance Orbiter.

While in orbit, this vision-based navigation system quickly processes the captured images to identify the exact crater and its position.  

“We have developed image processing algorithms specifically designed for space-grade FPGAs [Field Programmable Gate Array] enabling vision-based navigation to be accomplished within a few seconds,” explained JAXA. 

Following a successful precision touchdown demonstration, the lander will conduct scientific investigations, gather data, and capture images. 

Its multi-band spectral camera will study the composition of rocks believed to have originated from the lunar mantle to uncover the moon's origin. 

Findings from the lunar orbiter Kaguya indicate that debris ejected from the Shioli impact might include olivine sourced from the Moon's mantle. A more detailed examination of these minerals has the potential to provide insights into the moon's internal structure and its formation process.

The mission’s success will usher in a new era of exploration

SLIM's purpose is to demonstrate "landing where it is desired to land" despite the lunar surface's rugged terrain packed with craters and rocks. 

JAXA mentions that there have been no previous instances of precision landings on celestial bodies. 

"By creating the SLIM lander, humans will make a qualitative shift towards being able to land where we want and not just where it is easy to land, as had been the case before. By achieving this, it will become possible to land on planets even more resource-scarce than the moon,” mentioned JAXA mission description.

As a result, this pinpoint-landing technology might allow space agencies to land a robotic probe on any part of the moon or even on the alien terrains of our solar system's other celestial worlds.

One significant advantage of this technology is that it will enable in-situ examination of particular rocks or particular spots of great scientific significance. For instance, some ice-water-rich locations are located in the narrow areas of the moon’s pole.

It would be difficult for a robotic rover to navigate steep hills and rugged terrain along the path to reach specific locations. However, this small and cost-effective probe could easily do it. 

For these reasons, precise landing is critical for effective future exploration and unraveling our solar system's hidden secrets.