Mining the moon and Mars for 3D printing materials may sound like science fiction, but it will be crucial if we are to effectively explore deep space. After all, we can't bring everything we might need on such a long journey. But we can learn how to make these things in space, says Western engineer Jun Yang.
That's exactly what he and York University mechanical and space engineer Zheng Hong (George) Zhu, are doing. Their current project - a mix of space flight and medical applications research - is about perfecting artificial intelligence-enhanced methods for 3D printing in outer space.
The idea is to print the heavy, bulky equipment necessary for repairs and experiments using locally available materials. Scientists already know a fair bit about soil composition on the moon and Mars - two likely destinations.
Jun Yang
"The goal is to build infrastructure on Mars. However, if we want to launch something into space, it's very expensive," said Yang, a material, mechanical and biomedical professor. "We could use Moon soil or Mars soil in 3D printers to build everything we need there."
Such a strategy could also help the environment back on Earth.
That's because 98 per cent of a rocket's mass is fuel - fuel it needs to overcome Earth's gravity and launch into space. The remaining two per cent comes from the rocket and payload.
Yet drop even a small amount of the payload's weight by ditching some equipment, and you can substantially cut back on fuel. This not only reduces costs, it reduces the environmental footprint of rocket fuel.
The challenges and potential benefits of 3D printing in space revolve around microgravity and vacuum environments. The molten metals and plastics used to print equipment behave differently than they do in Earth's gravity.
"On Earth, when 3D printing lays down layers, gravity helps bonding between layers. In space, bonding is weaker because there is no gravity," said Zhu.
Another issue the pair will have to overcome: On Earth air flow helps dissipate excess heat from the printer and its products, while in space cooling is much harder because it's a vacuum.
With funding from the Canada Foundation for Innovation, Yang and Zhu plan to perfect their technique using a two-metre square vacuum chamber that fits both a 3D printer and the AI-enhanced robot that will operate it. This will allow them to experiment with approaches for overcoming issues with bonding and heat build up.
The pair is also experimenting with 3D printing biological substitutes such as skin grafts and organs for medical treatments in space and back home on Earth. The advantage of printing these soft tissues in space is that there is no gravity threatening to collapse their delicate 3D scaffolding.
"We can use space as a factory," said Zhu. "You fabricate it there and send it back here."
The researchers hope that within five years they will have functional prototypes of AI-enhanced 3D printing systems and scaffold-free 3D bioprinting technology ready for spaceflight.
"The big picture is if we want to explore big space, we need to understand this," said Yang. "We want Canada to be a major player in space exploration."
