4D Printing for Outer Space
Most of you surely know 3D printing. But are you also familiar with 4D printing? On our blog we already wrote about several uses of that method. Besides moving flowers 4D might actually take the space industry further.
One of the big problems with sending material into the orbit is the huge space these take, the weight and, of course, the costs. When sending equipment to space stations they range from about $ 9,000 to more than $ 40,000 per pound. Thus, NASA and the space industry desperately search for new solutions to tackle this problem. 4D printing might help to create payloads that are more compact and make the shipping easier and more efficient.
A 4D-Printed Solution
A team at the Georgia Institute of Technology created a pair of compact, unfurling structures that could pave the way for innovations in biomedical devices and offers great potential for space missions. The researchers are using „tensegrity“ when they crafted the object. Tensegrity is a structural system of floating rods in compression and cables in continuous tension, which are extremely lightweight while also being very strong. These so called 4D-printed structures can change their shape under certain conditions.
How does it work?
The struts of the model are made by 3D printers. The team designed the struts to be hollow, in order to make them capable of temporarily being folded flat. They have a narrow opening spanning the length of the tubes. These, then, are connected to a network of elastic cables, by attachment points at the end of each strut. So, in their post-printed stage the objects are flat.
The 4D printing part
Now you’re wondering how they become four dimensional? Well, temperature plays an important role here. When the objects are put into 149-degree water, they start to unfold. The researchers baked the speed at which that occurs directly into the print, using trial and error. This is an important step, because a large structure that deploys too fast implicates a big old mess of wires and rods and nobody wants that! So, when they printed, they came up with a technique that allowed them to print this “memory”, that is responsible for the speed of the unfolding, embedded in the struts. This also lets the structures return to their former state repeatedly.
With these properties, the system is perfect for space usage, because it unites strength with very little weight and space consumption.