Earth's orbit is so crowded that space traffic controllers issue more than 1,000 collision warnings per day

Paul Hennessy/NurPhoto via Getty Images

• Space junk has filled up so much of Earth's orbit that it's endangering satellites and astronauts.
• The company Kayhan Space issues roughly 1,000 space-collision warnings per day.
• Earth-orbit experts fear debris will cause an "unstoppable chain reaction" that cuts off launches.

So much junk is filling...