Testing Lunar Rovers on the Tottori Sand Dunes

The Lunar Surface Demonstration Field at the Tottori Sand Dunes serves as an experimental site for lunar surface development. This location was chosen for its resemblance to the lunar surface, including fine sand and undulating terrain. The project has captured the attention of several companies and research institutions. Notably, Bridgestone has already tested tires for lunar rovers at the site.

Tottori Prefecture aspires to become a hub for the space industry. To achieve this goal, it joined forces with Tottori University, renowned for its research on arid land. Together, they established the facility on land adjacent to the national park.

Flat Sandy Terrain and Long Slopes

The site was given the nickname "Luna Terrace." This is a combination of the Latin word "luna," meaning "moon," and "terrace," which sounds like "illuminate" (terasu) in Japanese. The name was selected from 896 entries in a contest organized by the prefecture.

"We need extensive, flat sandy terrain and long slopes for tire testing. And the Tottori Sand Dunes are a valuable location for this," explains Seiji Kon of Bridgestone's Elastic Grounding Body Development Unit.

On July 7, at the inauguration of Luna Terrace, Bridgestone tested tires for manned lunar rovers, made entirely out of metal. Rubber tires are ill-equipped to endure extended usage in an environment fraught with radiation. The moon also experiences huge temperature fluctuations, which can oscillate between -170°C (-274°F) to 140°C (284°F).

For earlier tests, the company used coastlines and off-road bike paths. However, the unevenness of the terrain hindered the progress of the trials. Luna Terrace also features a slope with a maximum gradient of 20 degrees.

"We wanted to develop tires that would sustain operations covering 100 kilometers [62 miles] or even exceeding 1,000 kilometers, but we struggled to find a stable, sandy terrain [for testing]," says Kon.

Advertisement

First Priority: Private Companies

Luna Terrace covers an area of 0.5 hectares. It was created on the grounds of the Tottori University Arid Land Research Center, located on the west side of the national park. To meet the diverse needs of users, the site is divided into three zones: flat, sloped, and free-design. The latter zone can be used for excavation and landscaping among other activities.

Construction began in 2022 and was completed at the same time as the neighboring 0.5-hectare demonstration field. This site is used for testing new technologies from the construction industry.

The private sector was the first to take advantage of the similarities between the Tottori Sand Dunes and the lunar surface. From 2016 to 2018, the lunar exploration team HAKUTO, operated by the space venture ispace, tested an unmanned exploration vehicle at the site. The team also used the site to evaluate the performance of its communication system and cameras for photo and video transmission. The company's subsequent project, HAKUTO-R, attracted attention in April when it attempted Japan's first moon landing. Unfortunately, it failed to achieve this goal. 

Topographic Similarities

Data shows that there are several similarities between the lunar surface and the Tottori Sand Dunes. This data was presented by the space technology group amulapo about half a month before the opening of Luna Terrace. The company was commissioned by Tottori Prefecture to conduct this research.

In this study, 3D maps and other data on the characteristics of the sand dunes were compared with NASA's lunar surface data. The company concluded that "the study confirmed similarities in terms of sand properties and other topographic attributes, albeit limited to certain areas of the moon."

These similarities include undulating terrains and slopes. Also, the properties of the sand in both areas are similar to that of typical sand when dry. Both the moon and the Tottori Sand Dunes consist of abundant fine and medium sand particles with comparable chemical compositions.

A Field of Dreams

Furthermore, the inauguration of Luna Terrace saw a test run of a lunar rover developed by Tohoku University students. According to Tottori Prefecture, it has been approached by about 10 other organizations, including businesses and universities, about using the facility. 

The Artemis Project, led by the United States, aims to return humans to the lunar surface in 2025 or later. Looking further ahead, it envisions the potential for a sustained human presence on the moon. This would serve as a stepping stone for an eventual manned mission to Mars.

The space industry is considered to be a burgeoning sector. In fact, it has an annual growth rate of 8%. Meanwhile, Tottori Prefecture aims to become Japan's leading hub for lunar-surface exploration, starting with the opening of Luna Terrace.

At the inauguration of Luna Terrace, Governor Shinji Hirai of Tottori Prefecture quipped, "There is no sutaba [Japanese shorthand for Starbucks] but plenty of sunaba [sandbox]."

Advertisement

On a more serious note, he continued, "The 'sandbox' has become a wonderful field — a field of dreams where people can shape the future."

RELATED: 

• Could Autonomous Robots Build a Base on the Moon?
• ispace Fails Moon Challenge but Gains Insight for Future Missions
• Hayabusa2 Asteroid Samples Offer Clues to the Origins of Life
• NASA to PM Fumio Kishida: 'Come Into Space With Us - Mars Awaits!'

(Read the article in Japanese.)

Author: Noriaki Matsuda