London Press Service
Informs
SPACECRAFT – HEAL THYSELF!
A material that could enable spacecraft to “heal” punctures and leaks automatically is being tested in simulated space conditions on Earth.
The self-healing spacecraft skin is being developed by Dr. Ian Bond and Dr. Richard Trask – from the Department of Aerospace Engineering at Bristol University in the United Kingdom – as part of a European Space Agency project.
The researchers have taken inspiration from human skin that heals a cut by exposing blood to air, causing it to form a protective scab. In humans, the air chemically reacts with the blood, hardening it.
In the airless environment of space, mechanical “veins” have to be filled with liquid resin and a special hardener that leak out and mix when the fibres are broken. Both must be runny enough to fill the cracks quickly and harden before it evaporates.
The researchers made a composite laminate material containing hundreds of hollow glass filaments 60 microns (thousandths of a millimetre) wide, each with an inner chamber of 30 microns in diameter. Half of the filaments are filled with an epoxy polymer or resin and the other half filled with a chemical agent that reacts with the polymer to form a very strong and hard substance.
The glass filaments are designed to crack easily when the overall composite material is damaged, causing both chemicals to leak out and rapidly plug the resulting crack or hole. “We have demonstrated we can restore strength by doing this,” said Dr. Bond, “and that it can stand the space environment.”
He imagined such cuts as analogous to the wear-and-tear suffered by spacecraft. Extremes of temperature can cause small cracks to open in the superstructure, and so can impacts by micrometeoroids – small dust grains travelling at remarkable speeds of several kilometres a second. Over the lifetime of a mission the cracks build up, weakening the spacecraft until a catastrophic failure becomes inevitable.
Dr. Bond and Dr. Trask have successfully tested the self-repairing material in a vacuum chamber to see whether it would work in a space-like atmosphere, and also investigated the effect of gravity on the skin’s protective properties when covering the top or the underside of a craft.
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New frontier: self-healing spacecraft skin that automatically “heals” punctures and leaks is being developed by Dr. Ian Bond (pictured) and Dr. Richard Trask at Bristol University’s Department of Aerospace Engineering. Here, Dr. Bond is testing materials on a tow placement machine funded by the South West Regional Development Agency. |
They now plan to develop stronger materials containing the healing filaments and to test them in even more extreme conditions, such as very high temperatures.
The promise of self-healing spacecraft opens the possibility of longer duration missions. The benefits are two-fold. First, doubling the lifetime of a spacecraft in orbit around Earth would roughly halve the cost of the mission. Second, doubling spacecraft lifetimes means that mission planners could contemplate journeys to distant destinations in the solar system that are too risky to attempt at present.
In short, self-healing spacecraft promise a new era of more reliable space vehicles, meaning more data for scientists and more reliable telecommunications possibilities for us all.
The UK currently captures more than 13 per cent of turnover in the world aerospace market and is second only to the United States in terms of market share, according to UK Trade & Investment, the government organisation that supports overseas enterprises seeking to set up or expand in the UK as well as UK companies doing business internationally.
The UK aerospace sector exports about 60 per cent of its 18bn pounds annual turnover, making it one of the country’s biggest exporting industries. It employs more than 150,000 people directly and more than 350,000 indirectly.
In 2006 it saw new orders increase by nearly six per cent to 26.2bn pounds. UK aerospace manufacturing is globally competitive. UK companies also have a significant presence overseas, employing 48,780 people and generating sales of 7.9bn pounds.
UK aerospace manufacturing provides high-value and highly skilled jobs. The latest data shows that 34 per cent of all employees in the sector hold a university degree or equivalent and is forecast to increase to 40 per cent by 2010.
By Brian Bel
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