Space, especially interplanetary space, is not as empty as one might think. There’s a lot of tiny particles of dust flying around and they could be a serious threat to spacecraft and other artificial probes.
In a paper, published in the Physics of Plasmas, researchers have modeled for the first time the interactions between dust particles and satellites we sent into space. These "hypervelocity impacts", as they are called, can create damaging electromagnetic impulses and now scientists think they know why.
“For the last few decades researchers have studied these hypervelocity impacts, and we’ve noticed that there’s radiation from the impacts when the particles are going sufficiently fast,” lead author Alex Fletcher from Boston University said in a statement. “No one has really been able to explain why it’s there, where it comes from or the physical mechanism behind it.”
It turns out, as particles hit the craft, they vaporize the target sending dust, gas, and plasma back into space. Electrons and ions in the plasma move at different speeds (having a significant mass difference) and this separation creates a radio emission. Understanding this could help engineers design safer space vehicles.
“More than half of electrical failures are unexplained because it’s very hard to do diagnostics on a satellite that fails in orbit,” continued Fletcher. “We believe we can attribute some of these failures to this mechanism.”
To discover this, Fletcher constructed a computer simulation of these impacts based on senior author Sigrid Close's existing theory about these damaging interactions. Back in 2010, Close suggested hypervelocity impact plasmas are responsible for satellite failures.
The simulation simplified the problem by not taking the released dust into account and just focusing on the plasma. The plasma expands in a perfect vacuum with ions and electrons spreading apart. The simulation provides data on the amount of radiation released by the plasma and by how fast the impacting dust has to be to create it.
The team next step will be to assess the radiation threat to satellites and create new simulations to better describe how the plasma behaves, so they can work out how to protect spacecraft from orbital debris.