The International Space Station is vulnerable from microparticles that zip across space at supersonic speeds, a new study has found.
Scientists from MIT developed cameras that could see in perfect detail the processes that take place when debris strikes the metal surface of the orbiting outpost. Then, they used the data to predict when a particle would "bounce off, stick, or knock material off of the surface to weaken it."
Details of the study appear in the journal Nature Communications.
Microparticles: The Good And The Bad
Microparticles traveling at supersonic speeds are not all bad; high-speed microparticle impacts can be useful in many circumstances such as cleaning surfaces or cutting materials. Sandblasting, for example, sends microparticles at insanely high speeds to smoothen rough, solid objects. In many cases, microparticles moving really fast could strengthen metallic surfaces.
The general understanding is higher velocities provide better results in industrial applications. However, microparticles can be extremely dangerous, too.
The researchers wanted to know the conditions in which the impact of a microparticle stops being effective as a coating or strengthening agent and starts destroying the surface of an object.
"We want to understand the mechanisms and exact conditions when these erosion processes can happen," stated Mostafa Hassani-Gangaraj, lead author of the study.
Microparticles Vs. The ISS
For the experiment, the team used tin as a model of the surface of the ISS and smaller tin particles, which are about a tenth of the thickness of the hair, to strike. The scientists also used one laser beam to accelerate the particles and a second laser to illuminate them as they strike.
The challenge, however, was recording the experiment. The MIT researchers created a microparticle impact testbed that can record impact rates of up to 100 million frames per second.
The study used the data accumulated from the study to predict how the surface of the ISS would respond to particles traveling at certain speeds. They deduced that a microparticle traveling at the speed of nearly 100 meters per second can cause degradation of the material. A microparticle traveling at the speed of nearly 1 kilometer per second can cause serious damage to a spacecraft and satellites.
The researchers hope that their findings can be used to improve erosion protection, whether on Earth or in outer space.