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Determining the Altitude of Iridium Flares

If you have a clear night and you're somewhat removed from city lights, many satellites are fairly easy objects to see. They look like faint stars (occasionally bright stars) gliding across the night sky. Sometimes satellites look like airplanes, but airplanes have blinking lights that are usually colored. What's interesting about Iridium satellites, from a star gazing point of view, is that they can suddenly brighten and may easily outshine every star or planet in the sky. Such dramatic "flaring" is a result of the special composition and configuration of the antenna on these satellites. I suspect that a number of future UFO sightings will be attributed to these things. You may be curious about how high Iridium satellites are as they wander across the sky. With just a little information, we can calculate the altitude of the Iridium satellites and the altitudes of other satellites as well.

Author(s):

James Foster, James FosterOwe Manfred, Owe Manfred

Date Accepted: 1999-10-28 Grade Group: High School (9-12) Benchmarks: M5.4.12 M8.4.2 Keywords: iridium flare tangent specular reflection satellite altitude orbit trigonometry of right triangles Microsoft Word: 07_13_99_1.docx PDF Document: 07_13_99_1.pdf