Is the stratosphere up for a gold rush?

A new generation of companies is targeting the higher reaches of the Earth's atmosphere as the space closer to it has become increasingly crowded with satellites [File: Getty Images]

When a Chinese balloon was shot down over the United States on February 4, it became a worldwide diplomatic scandal.

The US accused China of using the stratosphere – the area above 7 to 20 km in altitude, depending on the latitude – as a way to spy on the US. China responded with threats of its own and claimed the balloon was civilian and had meteorological purposes.