Robot excavators to build rocket blast shield walls using lunar boulders

Researchers have proposed that robots could be used to build a dry stone wall which will protect the lunar bases on the moon from the rocket exhausts on the launch pad.

A team of Swiss researchers have come up with the idea to use robotic hydraulic excavators which will function autonomously to build the proposed stone walls.

Moreover, they also suggest that the robots will use materials found abundantly on the moon as building blocks for the stone walls. The idea is being considered much cheaper than the alternative – which is transporting building material to the moon from the Earth.

According to estimates, the ring-shaped stone walls would ideally have a radius of 164 to 328 feet (50 to 100 meters).

The need for building stone walls around launch sites

Back in the day in 1969, the Apollo 12 mission crew had brought back parts from the Surveyor III lander. The lander had been dropped on the lunar surface in 1967.

Upon examination, the Surveyor III lander parts revealed that they had been damaged by the rocket exhaust and the dust which kicks up with every activity surrounding a launch.

Now with the Artemis mission , NASA aims to set up a colony on the moon. The colony will take help from SpaceX’s Starship Human Landing System (HLS) to take the people from one place to another and also for trips between the orbiting getaway and the moon’s surface.

This will lead to a lot of dust kicking up on the lunar surface, which can potentially damage not only the crafts but also the colonies which are proposed to be built.

Studies have shown that the lunar dust is capable of affecting regions far beyond the launch site.

Therefore, a protective ring or blast shield around the launch pads is considered an ideal solution for the problem.

Researchers on robots building walls on the moon

The paper assesses the viability of deploying robots toward the construction of key infrastructure on the Moon, using found boulders.

Due to the large size requirements, the researchers propose the construction of the stone wall only in the direction where shielding is really needed. They propose a quarter ring type of structure to protect the installations.

They used images taken by the Lunar Reconnaissance Orbiter (LRO) Narrow Angle Camera (NAC) to look for boulders which can be used for construction at two sites on the moon.

“The considered task thereby is to collect 250 m ³ of boulders, which is about enough for a quarter ring segment of a blast shield,” the paper says.

The proposed construction method is facing a series of challenges, some of which require further consideration.

A dry stone wall constructed using irregular, unprocessed boulders will contain small gaps. It needs to be examined, whether those gaps are an issue when the wall is used as a blast shield. This will require simulations and experiments under lunar conditions.

A further challenge is the travel distance and time required to collect the material and construct a blast shield.

A remaining challenge will be the recharging process. The robotic excavator thereby might either harvest energy by itself, rely on a few recharging stations, or could be powered by RTGs (radioisotope thermoelectric generators).

The study was first published in the journal Frontiers in Space Technologies .