New Materials for Scrunchy Sats

This defense technology journalism game isn't entirely expenses-paid trips and being served canapés while checking out the latest freebies handed out by the military-industrial complex's lavish PR arm. (Mainly it is , but not entirely.) Sometimes you have to do some actual research.

For example, a proposal for Pultruded Longerons for Furlable Truss Booms demanded some investigating. It's an exciting new technology – but what the heck is it?

Longerons, it turns out, are strips of material to which the skin of an aircraft or other structure are attached. Pultrusion is a technique from materials science:

Pultrusion is a continuous moulding process utilizing glass or other fibrous reinforcement in a polyester or other resin matrix.
Pre-selected reinforcement materials like fibreglass roving, matt or cloth, are drawn through a resin bath where all the material is thoroughly impregnated with a liquid thermosetting resin. The wet fibrous laminate is formed to the desired geometric shape and pulled into a heated steel die. Once in the die, setting of the resin is initiated by controlling precise elevated temperatures. The laminate solidifies in the exact shape of the cavity of the die as it is being continuously pulled by the pultrusion machine.

Composite Technology Development Inc who are aiming to develop these Pultruded Longerons expound the advantages of their material made by this method:

TEMBO® Elastic Memory Composites (EMC) combine the structural properties of fiber reinforced composites with shape memory characteristics of shape memory polymers. Components and structures fabricated with TEMBO® EMC materials can provide lightweight structures that are strong and stiff. Additionally, they can be folded, rolled, or otherwise packaged to a different shape for storage and later returned to the original as-manufactured shape, without loss of performance.

The idea is that a large structure – such as the antenna or solar cell array of a satellite, for example – can be made of the composite material, then scrunched up into a small volume so that it can fit into a launch vehicle. Once in orbit it can magically unfurl itself into its original shape without the need for any complex machinery or controls.

This is typical of the sort of small technological development that goes on behind the scenes. It lacks the glamour of the latest ray gun or UAV, but it may have bigger implications in future. This type of furlable material might one day lead to better umbrellas, self-
assembling tents, sun-roofs or even surgical stents. Military research into new materials leads in unpredictable directions. I suspect the man who was just trying to make a sword better than the bronze ones used by his neighbors wasn't planning on starting the Iron Age…