A whipple shield is a protective system composed of a series of thin layers of material spaced slightly apart. When a high velocity object impacts the shield’s first layer, it is destroyed and turned into a gas. This gas spreads out, and impacts the second layer over a much wider area, therefore with less effect. Eventually, the gas becomes too spread out and cannot penetrate the next layer. This method of protection is used extensively in the Internal Space Station and other orbital craft. It was invented by Fred Whipple.
Wikipedia: Whipple shield