If the Roman Empire could launch a satellite in a relatively high Earth Orbit – say about 1,200 km (750 miles) high – that satellite would only be close now. has fallen back to Earth. And if the dinosaurs had launched a satellite into the farthest geostationary orbit – 36,000 km (23,000 miles) or higher – it might still be up today.
Although we have only launched * satellites since 1957, these examples show how long objects can stay in orbit. With the growing problem of space debris collecting in Earth’s orbit, many experts have stressed for years that satellite operators need to figure out how to get rid of abandoned satellites at end of life.
The European Space Agency (ESA) and the United Nations Office for External Space Affairs (UNOOSA) have teamed up for a new infographic to show how long it would take satellites at different altitudes to fall naturally. back to Earth.
While the natural de-orbit process could be relatively fast for satellites flying at low altitudes – taking less than 25 years – for satellites launched into orbits tens of thousands of miles. kilometers away, it can be thousands of years before they return.
Gravity has little effect on the return of satellite to Earth. The biggest factor in reducing satellites in orbit is the amount of drag they receive from the Earth’s atmosphere. A satellite can stay in the same orbit for a long time because the Earth’s gravitational pull balances the experience of a centrifugal force satellite in orbit. For satellites in orbit outside the atmosphere, there is no air tension, so, according to the law of inertia, the speed of the satellite is constant and as a result orbit will be stable around the Earth for several years.
“If we look at our statistics, we have about 300 objects a year returning to Earth, burning up in the atmosphere,” Francesca Letizia, ESA’s space debris engineer, said in a podcast on space debris. “Under 500 km, the impact of the atmosphere, the spacecraft can appear within 25 years. At 800 km above the Earth, it will take about 100-150 years to fall back to Earth. “
Letizia said the biggest threat to old satellites that are not currently working is the risk of them exploding and creating more fragments, or of colliding with other satellites and the latter. some cause damage or destruction and also create additional substances in the Earth’s orbit.
Depth: This is what happens to a spaceship when it comes to the Earth’s Atmosphere
This means that when we launch satellites into space we need to consider how they will be removed at the end of their life, or else the area around the Earth will be filled with an old spaceship. which is in danger of being struck, exploded, and almost certainly. creating a lot of space waste.
Further reading: ESA