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Link to original content: https://web.archive.org/web/20061006102100/http://www.newscientistspace.com/article.ns?id=dn8623
A material that could enable spacecraft to automatically "heal" punctures and leaks is being tested in simulated space conditions on Earth.
The self-healing spacecraft skin is being developed by Ian Bond and Richard Trask from the University of Bristol, UK, as part of a European Space Agency (ESA) project.
The researchers have taken inspiration from human skin, which heals a cut by exposing blood to air, which congeals to forms a protective scab. "The analogy is the vascular system of the human body," Bond told New Scientist. "The system needs to be completely autonomous."
The researchers came up with a similar idea for protecting spacecraft. They fabricated 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, which causes both chemicals to leak out and rapidly plug the resulting crack or hole. "We've demonstrated we can restore strength by doing this," Bond says, "and that it can stand the space environment."
The pair then successfully tested the self-repairing material in a vacuum chamber to see whether it would work in a space-like vacuum, and also investigated the effect of gravity on the skin's protective properties when covering the top or the underside of a craft. 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.
Christopher Semprimoschnig, at ESA's European Space Technology Research Centre (ESTEC) in the Netherlands, is heading up research into self-healing technology at the space agency.
He hopes that it could protect spacecraft from micrometeroids. These are fragments of space debris just a few millimetres in size that may travel at several thousands of metres per second in orbit – fast enough to damage a satellite or crewed spacecraft, and cause serious damage.
The technology could also protect craft from leaks caused by the extreme temperatures of space travel. It could also safeguard against damage incurred during take off – an issue that has become a prominent concern for NASA following the shuttle Columbia disaster. A chunk of foam fell from the Columbia's external tank during take-off, and punctured the shuttle's left wing, leading to its destruction upon re-entry.
Other researchers are currently working on improved methods to detect potentially hazardous breaches in a spacecraft's hull. A team at Iowa State University, US, have developed a vibration sensor capable of pinpointing potentially dangerous air leaks from inside a craft.
But the first self-healing space vehicles may not be ready for launch for some time yet. "We have taken the first step but there is at least a decade to go before this technology finds its way onto a spacecraft," says Semprimoschnig.
10:00 06 October 2006
17:23 05 October 2006
