Why getting hit by space dust is an unavoidable aspect of space travel

Image: NASA

On June 8th, NASA revealed that its new powerful space observatory, the James Webb Space Telescope, is now sporting a small dimple in one of its primary mirrors after being hit by a larger-than- expected micrometeoroid out in deep space. The news came as a bit of a shock since the impact happened just five months into the telescope's space tenure, but such strikes are simply an inevitable aspect of space travel.

The space isn't empty despite what it is called. The regions between our planets are covered in tiny bits of space dust that can travel up to tens of thousands of miles per hour. Micrometeoroids are small pieces of asteroids or comets that are now in the vicinity of the Sun. They're all around. If they were all combined into a single rock, it would be about the size of a small island.

It's certain that your hardware will get hit by a piece of space rock if you send a spaceship into deep space. These protections will be built into the vehicles to shield them from strikes. Whipple shielding is a multi-layer barrier. The second layer is hit by smaller particles if the shield is hit by a Micrometeoroid. Extra protection is usually provided by using such shielding.

It is difficult with the James Webb Space Telescope. The telescope needs to be exposed to the space environment in order to gather light. The mirrors were built to resist some impacts, but they are more or less sitting ducks for larger strikes like the one that hit JWST. NASA underestimated the size of the micrometeoroid and it caused damage to one of the mirrors.

Spacecraft operators model the micrometeoroid population out in space to get a better idea of how often a spacecraft might get hit in any given part of the Solar System. It isn't a perfect system. David Malaspina, an astronomer at the University of Colorado, says that it's all probable. You can only say that you have a chance of being hit. That is up to chance.

Image: NASA

There are many origin stories for micrometeoroids. They can be debris from high-speed crashes in space. Small pieces of asteroids and comets break off when they are bombarded by space particles and light from the sun. A large planet like Jupiter can be torn apart by the strong pull of the asteroid's gravity. An object that gets too close to the Sun can cause the rock to break apart. Interplanetary micrometeoroids are just passing through our solar system.

The path the particles take around our star affects how fast they move. Depending on where your vehicle lives in space and how fast it is moving, they may or may not run into your spaceship. The closest human-made object to the Sun at the moment is NASA'sParker Solar probe, which is moving at a top speed of more than 400,000 miles per hour. Malaspina says, "It gets down to the 4-yard line, compared to Earth being all the way at one end zone" The densest part of the zodiacal cloud is a dense disk of space particles. The telescope would hit the particles at a slower rate, but the solar probe is hitting them at a much higher rate.

We have a pretty good idea of the population on Earth, even though we don't know much about the Sun. Fine smoke particles that can be measured can be created by a micrometeoroid hitting the upper atmosphere. The amount of smoke can tell us a lot. Materials have been placed on the outside of the International Space Station to see how often they are bombarded.

Image: NASA

It is close to 1 million miles away from Earth. The scientists have an idea of what's out there based on other missions. Most of the objects that hit the telescope are small. Spacecraft are hit by little ones a lot. The fractions are much, much, much smaller than a human hair. For most of the time, the satellites don't notice them. It was hit by small micrometeoroids four times before getting hit by a larger one.

In light of the recent impact, NASA has formed a new team to improve their models and better predict what will happen to the telescope. If an asteroid or comet breaks apart, current modeling will attempt to predict how debris will spread. It's harder to predict that kind of debris.

Predicting when a spaceship might get hit by a large amount of dust will give you more information. It's inevitable that one-off impacts will happen. It was an eventuality that NASA was always prepared for. Malaspina says, "You just have to live with the probability that you will be hit eventually by some sized dust particle."