Saturday, November 11, 2006

Iridium


were you thinking i was going to talk about the element or the satellite service. well, i found some cool stuff on hack-a-day about a recent burning man festival where they tracked solar flares reflected off the iridum communications satellites. you can see when you can see a flair in your neck of the woods, weather you be in the central or western neck at heavens-above.com. more on flares here

wired has a great article (from 1998, the start of the iridium service) that is well written, and tells the story of how a 3 man rogue group from motorola turned out a product that should have gone to governments but found a way to deliver it to the public sector. I particurally like the part how in 1991 they announced the plans to the public, but they forgot to get clearance from the FCC (and the worldwide counterpart) for frequency allocation. that could have been a show stopper. dating back to the 1945 erra, the satellite communcaitons idea was actually what gave birth to the application of geosynchronous orbits. its a little strange because the article says LEO (low earth orbit) was chosen because of the 1W limit they wanted in the handhelds, but ham uses 5 (and up to 7 in a pinch). maybe its because its 1.6ghz as opposed to 430mhz range. who knows. one other reason for non geo orbits was given, in that they'd need 30 foot dishes up there, but LEO is like 450miles away, so the arrays could be built much smaller.

one final thing, and jen, you can verify: supposedly iridium is 77 electrons? but as luck would have it, the final mesh ended up being 66 satelites due to the optimization. the name stuck, and

this is why all your chem students think iridium has 66 electrons

1 comment:

palegreenhorse said...

ya iridium has 77 electrons. i am just lucky if a student thinks that iridium has electrons let alone the right number...sigh.