Though scary, a smash-up of satellites is not unheard of. And it doesn’t always lead to devastation like that shown in the 2013 movie Gravity.
In 2009, the active communications satellite Iridium-33 hit the non-operational Russian craft Kosmos-2251. The collision created roughly 2,000 pieces of trackable debris circling the Earth at breakneck speeds.
If IRAS and GGSE collide tonight, experts say there might not be that many pieces of trackable debris. But even hundreds of pieces of new space junk pose the very real danger of causing a chain reaction in the increasingly crowded space above Earth’s atmosphere.
Kessler syndrome
The increasing the number of satellites cluttering Earth orbit has sparked fears of a cascading series of collisions — a result of what’s called Kessler syndrome or the Kessler effect. Each smash-up creates hazardous, uncontrollable, and hard-to-predict debris.
Fortunately, even if the two satellites do collide tonight, they will do so at altitude of about 560 miles (900 km). And since the International Space Station — which recently got a sensor to detect small pieces of space junk — orbits Earth at an altitude of about 250 miles (400 km), the lives of astronauts will not immediately be in danger. However, if the satellites do collide tonight, some of the debris will likely be sent upward into a higher orbit, while other pieces would spread downward into lower orbits, continuing to decay over time.