Pretty low. We’ve been putting stuff up there for over 50 years now, and there’s only been a handful of collisions. Its starting to get to the point where we have to worry about sending stuff up because some of the orbits are getting crowded. Folks are becoming concerned about the level of debris, but no one’s come up with a cost effective way (yet) to clear out the orbits.
Beeb article on the concerns about collisions. It looks like there’s a chance that other Iridium sats could be threatened by the debris.
Yes but there are successful satellite communication companies, so perhaps it was more due to mismanagement. Our company uses Inmarsat for live video, data transfer, and plain old telephony. The need is definitely there but it is expensive to use. It doesn’t do you much good at the poles BTW. The Inmarsat coverage gets poor at high latitudes due to the geostationary nature of the satellites which requires them to be over the equator.[/hijack]
In Georgia, satellites hit on YOU!
Inmarsat can have a higher data transfer rate than Iridiums or Globalstar (which is a similar system to Iridium). Last I heard, you could get 64Kbs with Inmarsat, while Iridiums peaked at 14K or so. You’re right about the high latitudes (and, for example, if you’re on the north slope a mountain in Canada, you’re SOL, as you can’t point the antenna in the direction of the bird, even though if you were on the ground, you could get a signal).
We get 128Kbs with Inmarsat, though it might just use two links in parallel.
I blame the Whig party’s inability to achieve platform consensus on the Kansas-Nebraska act. Bush is merely the “butterfly effect” result of those earlier events.
Iridium, of course, is not affected by this since the satellites are polar-orbiting. The system provides global coverage.
Inmarsat uses a network of 12 satellites in geostationary orbits; to get global coverage, Iridium uses 66 satellites in polar orbits (plus several spares). This very large number of satellites made the Iridium system very expensive to build and launch. Other satellite phone providers didn’t have as large of a start-up cost.
Globalstar has roughly the same number of sats as Iridium. They’ve had some financial problems, but not nearly to the extent that Iridium did.
As an aside, do a google search for heavens above and satellite.
The heavens above website does predictions for seeing the Iridium Satellite “flares” as well as the hubble, shuttle, ISS and many other satellites.
If you can see a bright Iridium “flare”, magnitude -5 to -8, they are pretty impressive.
though I guess there is now one less iridium to do the flaring 
Check out the site.
I think I recall an Economist article on such phones, they ended up seeking charitable concerns or UN operations to take up their service, lacking enough private customers.
Inmasat also started as a gov’t funded program to provide emergency maritime communications, so I don’t think they had to fund the original launch of the satellites.
Sorry for the hijack, but I’ve been wanting to see and photograph one of those flares for some time. I checked the website (I’ve been there before) and see that next Sunday there’ll be a magnitude -7 that I should be able to see. Here’s a link to the prediction. However I’m a bit confused about the location. It says that the azimuth of the flare is 342 degrees (NNW) but the map on the page shows it happening on the West, I’d say a 90 degree shift counter clockwise… so, what should I believe, the map or the data?
The map is just showing the path on the ground where the flare is the brightest in relation to your place on the ground. Does that make sense?
Just ignore the ground map unless you are using it to drive somewhere else to see it brighter.