Pressed into action

Astronauts on future NASA missions to Mars could remotely control a roving vehicle from their space suits using a touch-sensitive composite material discovered by a UK researcher.

The space agency hopes to create suits with four large textile buttons built into the glove cuffs. By pressing these, instructions would be relayed through the fabric to a radio frequency transmitter embedded in the suit. This would send a message to the rover’s control system using an RF link.

The suits will be fitted with a thin layer of Quantum Tunnelling Composites (QTCs), a range of polymers containing particles that are non-conductive in their normal state but allow electricity to flow through them when they are touched, twisted or stretched.

QTCs were discovered by David Lussey, and a team from NASA is currently in the UK working with his Darlington-based company Peratech to create the suits.

NASA and Peratech are also working on a project that uses the material to create a robot with tactile responses similar to those of the human hand. The resulting machine will be able to handle even the most fragile objects by applying a very light touch as well as providing feedback that will allow scientists to remotely build a picture of the object the robot is holding.

At present, conductive composite materials used to make switches and sensors contain metal or carbon atoms that are spaced so that they touch each other, allowing current to pass through the substance.

In QTCs, the conductive particles do not touch each other, but are around one nanometre apart. Conduction occurs due to ‘quantum tunnelling’, a function of quantum mechanics.

When force is applied to the material, through touch, twisting or stretching, the electrons pass between the conductive atoms by tunnelling through other particles. When integrated into textiles, the material is washable and remains undamaged attemperatures up to 250 degrees C.

It can be moulded into parts or applied as a surface coating but also has the potential to create self-resetting fuses, meaning that a single fuse could last for the lifetime of an electrical item. ‘If the current increases, the material heats up and will stop conducting when it reaches a certain temperature,’ said Lussey. ‘It will not then work until the current drains away. By altering the mechanical pressure applied to the material, QTCs can be used to replace different fuses.’

Other applications include the creation of efficient gas sensors. ‘By changing the polymer so that it is sensitive to volatile organic compounds, the material can form a sensor to detect vapours and gases,’ he said.

‘If the polymer is affected by a gas this has an impact on conduction, allowing substances in very low concentrations to be detected.’

QTCs are also suitable for sensors used in climate control systems and for thermal shutdown protection. When used as a surface coating, their unique properties mean that they reflect and absorb radio waves to provide radio frequency shielding for cables and antennae.

They could even be used to produce toys that respond to the pressure of a child’s touch, as well as more realistic and responsive computer game consoles.

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