Aluminium Hypervelocity Impact Target Bumper Shield/Whipple Shield

Aluminium Hypervelocity Impact Target Bumper Shield/Whipple Shield

This pair of aluminium sheets have been used to demonstrate a technique used to protect spacecraft from micrometeoroids - small pieces of rock or metal travelling incredibly fast, which are common in space. Micrometeoroids and other man made space debris pose a great risk to spacecraft and satellites, especially those that are designed to operate in space for many years. Bigger pieces of space debris can have catastrophic consequences for astronauts, spacecraft or satellites, as, at such speeds they can puncture materials creating holes.

To help combat this risk, scientists study terminal ballistics to experiment with extremely high-speed impacts - to simulate micrometeoroids that can travel up to 18 kilometres a second. These two pieces of aluminium demonstrate a Whipple Shield, invented by the American astronomer Fred Whipple. The idea is that by placing a protective bumper in front of the spacecraft, a small distance away from it, the force from the object striking it is dissipated. The space debris disintegrates as it passes through the bumper shield, spreading out the impulse over a larger area of the second piece of aluminium - therefore making sure the second piece of aluminium survives intact. This allows spacecraft to be made from thinner, lighter, materials, as the outer bumper shield offers the main spacecraft’s walls extra protection. The International Space Station has used exactly this technology to protect some of its most critical component parts.

In the case of these aluminium sheets, a high-velocity projectile has been fired through the first aluminium sheet making a significant entry hole. However, the bumper shield has done its job, proving the Whipple Shield concept, as the impulse of the projectile has been spread out - which can be seen in the multiple smaller dents in the second sheet of aluminium.