NASA recently announced that the James Webb Telescope was hit by a larger than normal micrometeorite. This caused damage to one of the telescope’s eighteen mirrors. Space dust can cause major problems for spacecraft, which is why the organization already takes this into account in the design.
We often think that space is empty, but it is not. The space between the various planets and stars is filled with, among other things, huge amounts of scattered gas and dust.
Dust particles can come from different sources, for example from asteroids. These micrometeorites orbit the sun and can reach speeds of tens of thousands of kilometers per hour. They are often smaller than a grain of sand and weigh less than a gram.
The James Webb Telescope has been hit by at least four different micrometeorites since its launch in December. NASA pointed out that contact with micrometeorites is unavoidable for a telescope of this size.
Shield of different layers
The space agency already takes this into account when designing spacecraft. Usually ships are equipped with some form of protection to stop micrometeorites. This is called the Whipple Shield.
The shield consists of a multi-layered barrier. If hit by a micrometeorite, the particle will pass through the first layer before further fragmenting. The second layer is then hit by even smaller particles. The shield is typically used around sensitive parts of spacecraft for added protection.
However, applying such a layer to the mirrors of the James Webb telescope is impossible, because then they will no longer be able to capture light. However, the mirrors are constructed in such a way that they can withstand impacts up to a certain height. However, the micrometeorite was larger than NASA had expected, causing damage to one of the mirrors.
Making a correct calculation is difficult
In any case, the space agency regularly calculates how often a craft will be hit by fragments and how quickly this will happen. However, it’s not a foolproof system, says space expert The edge†
The speed at which dust particles move depends on the part of the room they are in and the path they take. The possibility of them coming into contact with a spacecraft depends on where it is at the time and its speed.
Ultimately, it is inevitable that a spacecraft will be hit by a dust particle. All NASA can do is develop a craft that can withstand this to some extent.
The James Webb has managed to do just that so far: the impact has had no direct effect on the telescope’s operation. However, the mirror must be readjusted because of the distortion. It is not known if this has ever happened.