Japan Tests Robotic Earth-Moving Equipment in a Simulated Lunar Jobsite

Japan has embarked on an exciting new lunar program that will test automated remote construction machinery for the Moon. In 2021, representatives from the Kajima Corporation, the National Research and Development Agency, the Japan Aerospace Exploration Agency (JAXA), and the Shibaura Institute of Technology announced they would be working with the Ministry of Land, Infrastructure, Transport, and Tourism (MLIT) to develop a next-generation construction system (A4CSEL®) that will enable the creation of lunar infrastructure.

This new collaborative venture, known as the Space Unmanned Construction Innovative Technology Development Promotion Project, will create an A4CSEL system capable of operating in the harsh lunar environment. In a recent statement, Kajima announced that it would connect the approximately 20-square kilometer (7.72 mi2) Kashima Seisho Experimental Field with JAXA’s Sagamihara Campus. Here, they are conducting experiments to validate automated remote construction machinery in a simulated lunar environment, which could lead to the creation of a lunar base!

Since 2009, Kajima has been developing A4CSEL (“quad-accel”), a next-generation construction production system designed to transform “the construction site into a factory.” The technology is based on the concept of operating multiple automated construction machines with as few workers as possible, ensuring safety while reducing costs and eliminating waste. The technology has already been applied to several construction projects, mainly in the construction of dams and tunnels.

Since 2016, Kajima, JAXA, and multiple universities have been developing the A⁴CSEL technology to work on the Moon, emphasizing autonomous driving and remote control that can deal with lunar conditions. This includes extreme variations in temperature, lunar regolith, and lower gravity (roughly 1/6th of Earth’s gravity). In keeping with the philosophy of in-situ resource utilization (ISRU), their work has focused on creating A⁴CSEL applications to harvest lunar water ice deposits to generate hydrogen and oxygen propellants.

This is consistent with JAXA’s “International Space Exploration Scenario,” which emphasizes the need for in-situ resource utilization (ISRU) and building lunar bases within permanently shadowed regions (PSRs) on the Moon – such as lunar craters. For their experiment, Kajima and JAXA simulated the excavation of water-bearing lunar regolith using three construction machines (two backhoes and one crawler dump truck) modified for automated and remote control. The JAXA Sagamihara campus was used as the command center while the vehicles operated in the Kashima Seisho Experimental Field. As the representatives indicated in a recent JAXA press release:

“We demonstrated hybrid construction using automatic control and remote control based on an excavation and transportation work scenario assuming water excavation… Based on the results of this experiment on the ground using a real machine, we will build technology that can accurately reproduce work in virtual space, and if it becomes possible to reproduce work on the Moon under various conditions, it will be possible to. We believe that the results of this demonstration can be reflected in work on the lunar surface.”

While the conditions were not analogous to the lunar environment for this experiment, the joint JAXA-Kashima team demonstrated the effectiveness of their automatic operation and remote control system using multiple vehicles. Similarly, the team combined laser range finder (LIDAR) data with simultaneous localization and mapping (SLAM) algorithm to create a map of the surrounding environment, which allowed the team to keep track of the positions of their vehicles. This demonstrated that their autonomous/remote control technology can function in environments where there is no Global Navigation Satellite System (GNSS).

For their next step, the participants in this collaborative venture will continue to develop a simulator that incorporates experimental results with lunar surface data. This will allow them to gradually test the technology in environments increasingly analogous to the lunar surface. At the same time, Kashima anticipates their experiments and the SLAM algorithm will have spinoff applications here on Earth. As Kashima’s representatives indicated in the press release:

“SLAM, which was used as a positioning technology in this experiment, can be used as a simultaneous and dynamic positioning technology for multiple machines, which is essential for automating tunnels and underground construction where GNSS cannot be used, even on Earth. In addition to the accuracy improvement measures verified in this activity, we plan to utilize SLAM at sites around the world.”

Caveat: This information is translated from a Japanese-language press release.

Further Reading: JAXA