I once met with Iridium [1] engineers not long after the collision of one of their satellites with a Russian weather satellite [2] in 2009. The meeting was for

I once met with Iridium [1] engineers not long after the collision of one of their satellites with a Russian weather satellite [2] in 2009. The meeting was for another purpose entirely, but since the collision was fresh news, it naturally came up in conversation. The Iridium folk told me that they would receive warnings from NORAD of imminent collisions, defined as two satellites coming with 500m. They were receiving warnings to the tune of 10 or 12 a day, so many that they basically started ignoring them. [1] https://www.iridium.com/ https://www.iridium.com/ [2] https://en.wikipedia.org/wiki/2009_satellite_collision https://en.wikipedia.org/wiki/2009_satellite_collision