Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to [email protected].
How is the International Space Station able to orbit without burning up? – Mateo, age 8, New York, New York
Flying through Earth’s orbit are thousands of satellites and two operational space stations, including the International Space Station, which weighs as much as 77 elephants. The International Space Station, or ISS, hosts scientists and researchers from around the world as they contribute to discoveries in medicine, microbiology, Earth and space science, and more.
One of my first jobs in aerospace engineering was working on the ISS, and the ISS remains one of my favorite aerospace systems. I now work at Georgia Tech, where I teach aerospace engineering.
The ISS travels very quickly around the Earth at 5 miles per second (8 kilometers per second), which means it could fly from Atlanta to London in 14 minutes. But at the same time, small chunks of rock called meteoroids shoot through space and burn up when they hit Earth’s atmosphere. How is it that some objects – such as the International Space Station – orbit the Earth unscathed, while others, such as asteroids, burn up?
The ISS moves quickly while it orbits the Earth.
To answer why the ISS can stay in orbit for decades unscathed, you first need to understand why some things, such as meteoroids, do burn up when they enter our planet’s atmosphere.
Why do meteoroids burn up in the atmosphere?
Meteoroids are small chunks of rock and metal that orbit the Sun. These space rocks can travel between 7 and 25 miles per second (12 to 40 km per second). That’s fast enough to cross the entire United States in about 5 minutes.
Sometimes, the orbit of a meteoroid overlaps with Earth, and the meteoroid enters Earth’s atmosphere – where it burns up and disintegrates.
Even though you can’t see them, the atmosphere is full of a combination of particles, primarily nitrogen and oxygen, which make up the air you breathe. The farther you are from the surface of the Earth, the lower the density of particles in the atmosphere.
The atmosphere has several layers. When something from space enters the Earth’s atmosphere, it must pass through each of these layers before it reaches the ground.
Meteoroids burn up in a part of Earth’s atmosphere called the mesosphere, which is 30 to 50 miles (48 to 80 kilometers) above the ground. Even though the air is thin up there, meteoroids still bump into air particles as they fly through.
When meteoroids zoom through the atmosphere at these very high speeds, they are destroyed by a process that causes them to heat up and break apart. The meteoroid pushes the air particles together, kind of like how a bulldozer pushes dirt. This process creates a lot of pressure and…
