Liquid resin fabrication in microgravity

Janine Liberty

The future of human life outside of Earth will heavily depend on the ability to fabricate and manufacture things. Yet fabrication in space poses numerous difficulties. Some of these challenges include storage space in vehicles, availability of raw materials, lack of machines, and shortage of manpower. 

 Other challenges in fabricating objects in space are simply a result of  the  different  physical environment;  the lack of gravity introduces unexpected material  behaviour, as other forces aside from gravity become dominate. Surface tension, for example, becomes very dominant in determining the shape of liquid materials and adhesion between liquids and other materials also plays a more dominant role. 

Because of the reasons stated above, 3D printing in space was conceptually limited to fused deposition modeling (FDM) technologies, which are less susceptible to problems resulting from the harsh conditions. Liquid- or powder-based printing technologies are assumed to be very problematic for space fabrication because of liquid behavior in microgravity conditions. On the other hand, FDM technologies have a lot of limitations such as the inability to create transparent  structures or layerless shapes with defined smooth curvatures.

In this experiment, we would like to harness surface tension's dominance in liquid behavior under zero gravity conditions  to create various controllable and accurate, layerless and transparent geometries using UV-curable resin. The resin will be hardened using a high-power UV light source.

We will focus on rapid fabrication (in under 17 seconds) of the following shapes:

  1. Shapes that are hard to make on Earth without special machinery, e.g., perfect lenses.
  2. Shapes and materials that could be necessary in the space environment and are hard to make with existing methods available in space, such as ball bearings.