On June 8, NASA revealed that its powerful new space observatory, the James Webb Space Telescope, already has a small dome in one of its main mirrors after being dropped by larger-than-expected microscopic meteors into deep space. The news came as a bit of a shock, as the strike came just five months after the space telescope’s tenure – but strikes like these are simply an inevitable aspect of space travel, and more attacks are sure to come.
However, as its name suggests, the space is not completely empty. Within our solar system, small pieces of cosmic dust travel through the regions between our planets at gigantic speeds that can reach tens of thousands of miles per hour. These small meteorites, no larger than a grain of sand, are often small pieces of asteroids or comets that have disintegrated and now orbit the sun. They are everywhere. Estimate of small meteorites in the inner solar system. Their total mass is estimated at 55 trillion tons (If they were all combined into one scale, it would be the size of a small island).
Small particles of cosmic dust are spreading in the regions between our planets at enormous speeds
This means that if you send a spaceship into deep space, your tools will surely crash into one of these small pieces of space rock at some point. Knowing this, spacecraft engineers will build their vehicles with certain defenses to protect themselves from micrometeorite impacts. They often include something called Whipple shielding, which is a special, multi-layered barrier. If the shield is hit by a small meteor, the particle will pass through the first layer and fragment further, so that the second layer will collide with smaller particles. This shielding is typically used around sensitive spacecraft components to provide additional protection.
But with NASA’s or JWST’s James Webb Space Telescope, it’s more complicated. Gold-plated telescopic mirrors must be exposed to the cosmic environment in order to properly collect light from the distant universe. And while these mirrors are designed to withstand a bump, they’re kind of like a sitting duck for bigger micrometeroid bumps, like the one that hit the JWST in May. Although the micrometeorite was still smaller than a grain of sand, it was larger than NASA expected – enough to damage one of the mirrors.
Spacecraft operators are modeling groups of microscopic meteorites in space to better understand how often a spacecraft can be struck in a part of the solar system – and how large the particles can hit its instrument. But until then, this is not a reliable system. “It’s all a possibility,” said David Malaspina, an astrophysicist at the University of Colorado who focuses on the effects of space dust on spacecraft. the edge. “You can just say, ‘I have a chance to hit that particle size.’ “But whether you do it or not, it’s a coincidence.”
Examples of different types of Whipple shielding Photo: NASA
Micrometeorites have a wide range of origin stories. They can be the remnants of high-velocity collisions in space that shatter space rocks into small pieces. Asteroids and comets have also been bombarded over time by cosmic particles and photons from the Sun, causing small pieces. The asteroid may also approach a planet as large as Jupiter, where strong gravitational pull pulls pieces of rock. Or an object can get too close to the sun and get very hot, causing the rocks to expand and break to pieces. There are even microscopic interstellar meteorites that simply pass through our solar system from distant space quarters.
Micrometeorites have a wide range of origin stories
The speed at which these particles move depends on the region of space in which they are located and the path they travel around our star, an average of about 45,000 miles per hour or 20 kilometers per second. Whether or not it will hit your spacecraft also depends on where your spacecraft lives in space and how fast it moves. For example, NASA’s Parker solar probe is the closest man-made object to the sun at the moment, traveling at a top speed of more than 400,000 miles per hour. “This is up to the 4-yard line, compared to Earth, which is down at one end,” said Malaspina, who focused on studying the effects of micrometeorites on the Parker solar probe. It also moves through the densest part of a region called the zodiacal cloud, which is a thick disk of cosmic particles that penetrates our solar system. So the Parker solar probe is sandblasted more often than JWST – and collides with these particles at incredibly high speeds than a telescope could.
The Parker solar probe gives us a better understanding of the micrometeoroids around the Sun, but we also have a better understanding of the population around the Earth. When a small meteor hits the upper atmosphere around our planet, it burns and creates meteor smoke – small, measurable smoke particles. The amount of this smoke can tell us how much dust hits the Earth over time. There were also experiments at the International Space Station, where the material was installed on the outer surface of the orbital laboratory to see how often it was bombed.
NASA Parker Solar Probe Art Exhibition Photo: NASA
While JWST lives about a million miles from Earth, it is still relatively close. Scientists also have an idea of what is based on other missions sent into orbit similar to that of JWST. Most things that hit the telescope are not so important. “A spaceship hits small children all the time,” says Malaspina. “I mean a few parts of a micron – much smaller than a human hair. And for the most part, spaceships don’t even notice it. ” In fact, JWST had already been hit by four small meteors before hitting the larger micrometeorite in May.
“You just have to live with the opportunity to be hit in the end.”
NASA is modeling the micrometeorite environment before the JWST launch, but in light of recent impact, the agency has assembled a new team to improve its models and better predict what could happen to the telescope after future impacts. Modeling current micrometeorites will try to predict things like how debris will spread through orbit if an asteroid or comet crashes. This type of wreck is more dynamic, says Malaspina, making it harder to predict.
However, at the end of the day the forecast will just give you more knowledge of when a spaceship can hit a big speck. One-off effects like this are simply inevitable. The JWST eruption will continue over time, but it was an opportunity that NASA has always been preparing for. “You just have to live with the opportunity to end up with dust-sized particles and do your best with engineering,” says Malaspina.
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