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Iridium Repurposed For Science
Elvis Maximus writes " An article in today's New York Times describes how Iridium satellites' orientation sensors are being used to track currents in the Earth's magnetic field." The NYC Times, of course, wants registration info, so you'll have to make another account - but it's good to see at *someone* is using Iridium, cuz the customers certainly didn't.
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You are both wrong. The answer is neither to avoid them completely or to roll over simply because they want to place controls on how you can view and use the information on their page.
Ever since they started spreading stories out across multiple pages, I have been planning a program to get around their broken ideas of presentation. What I want to do is write a script using perl and lynx to download the complete nytimes everyday, in a one-page-per-article format, with a single big index page that links to all the articles, and archive it on my disk.
This could be set to run at 3am every night, making for much speedier consumption of the times when I get up in the morning, making my day a tiny bit more efficient. The fact that you would build up a searchable archive of the paper over time would also be highly useful. Who wants to pay two bucks for an article just because its a week old ?
You'd have to maintain the script against their periodic redesigns. If I ever get the energy, I'll do it one weekend and then post it on freshmeat.
The reason why I this would solve the account/privacy/tracking issue, is that I'd make it have a rotating set of accounts and it would use a different one for each article. There would be a simple text file with "account_name password" format, so that people could trade and merge these files, totally screwing tracking because random stories would be loaded from each account from different machines.
I guess my moral is that if you care, no one can put content on the internet and also control and meter access and use. All you have to do is sit down, and write the program that makes it easy for all the idiots out there to do what they want.
One last thing -- if they'd put all their articles on a news server I'd never visit the web page, I think the news group format is best for fast efficient consumption of the morning paper (well, best electronically -- I still cannot read the same amount of information as I can if I have the actual printed version in hand.)
I was talking to a previous sales person for Iridium .. she says that phone calls rarely lasted more than one handoff .. she says the sattelites would hand off the call with no ACK, so if the signal didn't bounce properly, the call was lost, which happened frequently.
I have NO proof to back this up, just the word of a salesperson, so attack me not.
We emerge from our mother's womb an unformatted diskette; our culture formats us.
We emerge from our mother's womb an unformatted diskette; our culture formats us. - Douglas Coupland
Speaking of science, how do astronomers feel about having to put up with continued flares now that Iridium has been "rescued"?
Free Hans!
How many science projects can get 70 satellites for $72 million? Almost 1 million per satellite. You couldn't get a better a bargain than that even if it were on ebay.
Motorola spent billions to create the Iridium satellite telephone system, allowing anyone almost anywhere to make a phone call. Unfortunately, not many people found much reason to lug a cumbersome phone to a remote place and pay several dollars a minute for the service.
Scientists, however, found a very good use for it.
With the help of Iridium's constellation of more than 70 satellites circling 470 miles above the ground, the scientists have collected a bounty of information about electric currents in the upper atmosphere, data they could not have obtained otherwise.
"We need measurements to make the invisible visible," said Dr. Brian J. Anderson of Johns Hopkins University's Applied Physics Laboratory in Baltimore, who led the effort.
The sun spews out charged particles traveling at a million miles per hour known as the solar wind. The bombardment of the solar wind would be deadly to life on Earth, but Earth's magnetic field deflects the streams of charged particles -- electric currents, in essence -- and either deflects them around the planet or channels them toward the North and South Poles. The currents themselves cannot be seen, but they power the colorful, flickering nighttime display of the aurora borealis -- what in the Northern Hemisphere is known as the Northern Lights -- and the aurora australis in the south.
When the sun sends out a strong puff of charged particles, these auroral currents can disrupt radio signals, damage power grids and puff out the Earth's atmosphere to drag down satellites. The new knowledge should help scientists better understand such "space weather."
The orbits of the Iridium satellites pass directly over the North and South Poles, providing an ideal downward observing perch of the polar regions. Several years ago, Dr. Anderson realized that the magnetic sensors that the Iridium satellites use to orient themselves are sensitive enough to detect the 1 percent fluctuations in the Earth's magnetic field caused by the auroral currents.
Since February 1999, the operators of the Iridium system have been shipping the magnetic field data to Dr. Anderson and his collaborators, who then calculate the position and strength of the currents. The large number of satellites means they can detect fairly quick shifts in the currents. A second, ground-based system provides a complementary snapshot of the auroral currents.
Eight radar dishes in the Arctic known as the Super Dual Auroral Radar Network, or SuperDARN, measure the electric fields emitted by the charged particles. Multiplying the electric fields measured by SuperDARN with the magnetic fields from Iridium tells how much power is flowing into Earth from the solar wind. The data showed that the power flow was often concentrated in "hot spots" and could change quickly. On one day in March, the power jumped from 17 billion watts to nearly 50 billion watts in two hours.
"They are much more complex than we thought previously," Dr. Anderson said.
For now, the flow of data coming down from Iridium continues, but it may not last long. A partnership set up by Motorola to run the satellite system went bankrupt in August 1999 and had announced in March that it was going to shut down the satellites and crash them into the ocean. But a new $72 million contract from the Pentagon will keep the satellites up for at least two years.
Even if Iridium is eventually ditched, the collected data could enable scientists to estimate the currents based on the brightness of the Northern Lights.
Richy C.
Look here
They are in six orbital planes, 11 operational satellites per plane, with a few spares here and there. In LEO (low Earth orbit) their orbital period is about 90 minutes, which means that for any given user, a satellite will be overhead for maybe ten minutes max before having to switch off to another satellite. Since the Iridium phone is omindirectional, the new satellite just has to take over the CDMA signal and you get to keep on talking. Since the satellites are usually beaming the signal among themselves to a satellite over a downlink station, it isn't too hard to take one out of the loop and put another in. Hope that clears things up. Can post more if this isn't already over the heads of most readers here.
We should have a 'Iridium' topic instead of bundling it all into Science - just so we can 'deactive' the stories showing...
Richy C.
As one of those "lucky" few who actually tried out the phones, I wanted to pass on a few thoughts.
The Iridium system ultimately failed commercially because it just didn't perform. Sure you could do some neat stuff with it (as we actually tested such as call in flight between planes by pointing the antenna out the window) but get the darn thing anywhere near a built up area such as a city and it had trouble picking up a satellite. The plan for the system to use local wireless phone systems where available (such as GSM in Europe) just didn't work as advertised. $7 per minute doesn't cut it. There just aren't enough people who operate outside wireless system footprints who can affort the price to make the system commercially viable.
With so many satellites threatening to just burn up in the atmosphere, I'm in favor of whatever good usage can be made of this system. There have been a few posts complaining about the military's use/buy out of the system and I think they're dead wrong. If the military had not stepped in with funding to keep it aloft, there might not have been any scientific use of the system at all.
The military will use Iridium, ironically enough, exactly how it was intended: for quick phone service outside areas where other commercial wireless phones don't work. Up until, the military relied heavily on INMARSAT which was bulky and for which military use was not really permitted under the usage agreement and bylaws.
Getting to the stories through channel.nytimes.com allows you to see the stories without registering. Here's that Iridium story.
Do domain names matter?