The US military is brainstorming ways to build large structures in space, from telescope antennas to elevator tethers. By growing these objects in microgravity using biological organisms, they hope to avoid the costly and painstaking process of launching components from Earth.
鈥淲e have yet to unlock the potential of biology for space production and manufacturing,鈥� says , program manager for the US Defense Advanced Research Projects Agency (DARPA). The combination of biology and mechanical engineering could unlock new ways to 鈥渕anufacture at unprecedented sizes in space鈥�, he says, but acknowledges that 鈥渢he devil will be in the details鈥�.
DARPA envisions growing 鈥渂iomechanical structures鈥� at least half a kilometre long, such as new modules for a commercial space station or long tethers for space elevators linking Earth鈥檚 surface and orbit. Other possibilities include huge nets for collecting orbital debris or even 鈥渒ilometer-scale鈥� antennas for radio astronomy telescopes, according to a posted 25 February on a US government website for federal contracts.
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To be useful, these biological structures must be able to grow in the desired directions and integrate with electronics and other structural materials. 鈥淢aking fully 鈥榞rown鈥� large-scale structures is beyond the capabilities of today鈥檚 technology,鈥� says at the Francis Crick Institute, a biomedical research centre in the UK. 鈥淭hat is the aspect where this program has the potential to move the needle and develop new technology.鈥�
Directional growth on a large scale has so far only been demonstrated in multicellular organisms such as trees or underground networks of fungi, says at the University of Florida. Some researchers have tried creating engineered living materials from unicellular organisms such as microbes, but they have yet to achieve precise control over their final formed shapes.
鈥淐ontrolling this artificially 鈥� especially without gravity, which many life forms rely on to determine a direction 鈥� is still difficult,鈥� says Averesch. 鈥淓ven if directionality of growth could be controlled also in microgravity, the space environment is incompatible with biological activity.鈥�
They would also probably need to launch 鈥渟ignificant amounts鈥� of material into space to feed the growing biological structures, which could outweigh the benefits of the approach, says Averesch.
