What altitude must satellites reach to stay permanently in orbit?
Getting a satellite into orbit is hard enough, and staying in orbit means avoiding atmospheric drag.
Asked by: Ludo Webb, Manorhamilton
Getting satellites into orbit is hard enough - they need to be hurled into space with enough energy to reach around 26,000km/h. But staying in orbit means avoiding losing energy to the Earth's atmospheric drag. While the official threshold of space is 100km above the Earth, the effects of the atmosphere can be detected much higher.
Even Hubble, which orbits at almost 600km, could be brought down by the creeping effect of drag. Only satellites in orbits several tens of thousands of kilometres above the Earth can be regarded as effectively permanent, though even they are not totally immune to atmospheric drag.
Read more:
Authors
Robert is a science writer and visiting professor of science at Aston University.
Sponsored Deals
Spring Savings!
- Try your first 6 issues for just £9.99 when you subscribe to BBC Science Focus Magazine.
- Risk - free offer! Cancel at any time when you subscribe via Direct Debit.
- FREE UK delivery.
- Stay up to date with the latest developments in the worlds of science and technology.
