The best thing since sliced bread: Graphene – the chemical sensor and strain detector.

Tiny sensors are being developed to detect trace elements within the Earth’s upper atmosphere, and structural flaws within spacecraft.

Mahmooda Sultana, an expert from NASA, and her team are working on two new research and development efforts utilising the material graphene, the ‘superfood’ of materials, which was discovered in 2004. Graphene is composed of an atomic scale ‘chicken wire’ structure, where carbon atoms are arranged in a hexagonal array just one atom thick. Graphene is manufactured in a simular manner to computer chips, where gases are reacted with a starting material under vacuum, to decompose it to produce the desired thin film.

The unique selling point of graphene is that it is the strongest material ever measured but it is also the most sensitive and stable, at extreme temperatures. It is the combination of these extreme properties which make the material so versatile and useful to engineers and material scientists.

A new application for this material is to detect atomic oxygen within the Earth’s upper atmosphere. Atomic oxygen particles are produced when oxygen molecules within the Earth’s atmosphere are broken apart by ultraviolet radiation from the sun, they are highly corrosive and ruin the material used to make spacecraft.

Graphene sensors oxidise as they absorb atomic oxygen, which produces a change in the electrical resistance that can be correlated with the density of oxygen within the atmosphere. This kind of sensor can also be used to detect other gases, and to investigate the role of atomic oxygen in creating atmospheric drag as well as its effect on spacecraft.

NASA are also collaborating with the Massachusetts Institute of Technology to use graphene to detect stresses within spacecraft components by embedding microsensors within the composite material. The ultimate aim will be for these sensors to work autonomously.