Oak Ridge National Laboratory/Department of Energy
Researchers at the Department of Energy’s Oak Ridge National Laboratory (ORNL), in collaboration with NASA, have used 3D printing to develop the same kind of wheel as the design used by the space administration for its robotic lunar rover. Oak Ridge says the project demonstrated the potential of additive manufacturing for creating highly specialised parts needed for space exploration.
The 3D printed wheel was modelled on the existing, light-weight wheels of the Volatiles Investigating Polar Exploration Rover, or VIPER, a mobile robot NASA plans to send to space in 2024 to map ice and other potential resources at the south pole of the moon.
The NASA mission is intended to help determine the origin and distribution of the moon’s water and whether enough could be harvested from the moon’s surface to support people living there.
While the prototype wheel that was 3D printed at DOE’s Manufacturing Demonstration Facility (MDF) at ORNL will not be used on the NASA Moon mission, it was created to demonstrate the same design specifications as the wheels made for NASA’s VIPER.
Oak Ridge says that additional testing is planned to validate the design and fabrication method before using this technology for future lunar or Mars or considering it for other space applications, such as large structural components.
Oak Ridge National Laboratory/Department of Energy
NASA mechanical design engineer Richard Hagen, left, and ORNL researcher Michael Borish inspect a lunar rover wheel prototype that was 3D printed at the Manufacturing Demonstration Facility.
MDF researchers 3D printed the rover wheel prototype at ORNL in late 2022. A specialised 3D printer used two coordinated lasers and a rotating build plate to selectively melt metal powder into the designed shape.
Oak Ridge says that the 3D printer used for the rover wheel prototype is large enough for a person to enter, and is unique in its ability to print large objects while the steps occur simultaneously and continuously.
“This dramatically increases the production rate with the same amount of laser power,” said Peter Wang, who leads MDF development of new laser powder bed fusion systems at Oak Ridge. “We’re only scratching the surface of what the system can do. I really think this is going to be the future of laser powder bed printing, especially at large scale and in mass production.”
Oak Ridge says that although the machine is unique, a key to the success of the project was researchers’ expertise in process automation and machine control. They used software developed in house to slice the wheel into vertical layers, then balance the workload between the two lasers to print evenly.
Read more:
nano3Dprint announces partnership with Finite Space for 3D printed lunar rover
Incus reports success following ESA-supported project exploring 3D printing in lunar environment
ICON awarded $57.2 million NASA contract to develop lunar 3D printing construction system
Brian Gibson, the researcher who led the rover wheel project for ORNL said: “The project with NASA really propelled the technology forward. It was great to connect a capability with a developing need, and the team was excited to be making a prototype component with space exploration applications.”
Made of a nickel-based alloy, the prototype wheel is approximately eight inches wide and 20 inches in diameter, which ORNL says is much larger than typical parts 3D printed with metal powder bed systems, and that additive enabled greater complexity in the rim design without added cost or manufacturing difficulty.
The four VIPER wheels that will churn through moon dust when the rover launches in 2024 require multiple manufacturing processes and assembly steps. VIPER’s 50-piece wheel rim is held together with 360 riveted joints.
Oak Ridge says that if NASA testing proves the 3D printed prototype to be as robust as conventionally built wheels, future rovers could instead use a single 3D printed wheel rim, which took ORNL 40 hours to manufacture.
Oak Ridge National Laboratory/Department of Energy
A close up of the 3D printed wheel
“A lot of these wheel features were put in just to highlight what you can do with additive manufacturing,” said Richard Hagen, a mechanical design engineer for NASA and additive manufacturing lab manager at NASA’s Johnson Space Center in Houston. “It lets you easily implement design features that are hard to implement with traditional tooling or even a traditionally machined part.”
NASA plans to test the 3D printed wheel’s performance on a rover, either in the rock yard at NASA’s Johnson Space Center or in a giant ‘sandbox’ of simulated lunar rocks and soil at a contracted test facility. Evaluators will assess the wheel’s manoeuvrability, pivoting resistance, sideways slippage, slope climbing and other performance metrics.
Hagen said: “Being able to build parts in space for repairs will be important, because you can’t just take enough spares. Powder, pellets or filament for printing are a lot easier to pack and would allow for more flexibility.”
Gibson added: “Additive manufacturing offers the flexibility that if you have the feedstock, you could make any replacement part you need, whether in space or on Earth. This is a reason additive manufacturing has generated significant interest for a range of replacement needs, from rapidly manufactured tooling to hard-to-source castings and forgings. For space exploration and habitation, 3D printers couldeventually use local material from the moon or Mars as a feedstock.”
In issue 31.5 of TCT Magazine Europe, TCT spoke to various experts in the field of 3D printing with materials found locally in space, which can be read here.
