www.bbc.co.uk/news/science-environment-38613275
The Iridium Company starting to replace the old satellites in their network and hope to complete the job by mid 2018, but....
One thing the new satellites will not be capable of doing, however, is producing Iridium "flares". These are the flashes in the sky that result when sunlight glints off the antennas of the old spacecraft.
The new satellites do not have the same configuration, so once the original constellation is de-orbited the flashes will cease.
"I'm afraid those who've been tracking that phenomenon over the past 20 years have another year or two to see it," Mr Desch told BBC News.
"As someone who's seen a couple myself, you can imagine what a thrill it is to be the CEO of a company like this and watch your satellite go overhead. But we weren't going to spend money just to make angular shiny things on our satellites, so that phenomenon will go away - but it's been fun."
  