Another close call...
Yesterday the International Space Station (ISS) was ordered to maneuver to avoid collision today with a 4 inch piece of space junk which is said to be a remnant from a Chinese satellite rocket engine traveling at a speed of about 20,000 mph. The shuttle Discovery fired it's thrusters to reorient the ISS out of harm's way. Thankfully, the collision warning was given early enough to allow for evasive maneuvers. During the previous close encounter, with the 5 inch Russian debris, such advance warning was not given. Instead, the astronauts were told to wait in the Soyuz capsule for possible orders to depart from the ISS. Evidently, the path of the Russian debris is much more difficult to predict because it has been bouncing off Earth's atmosphere. Each bounce, of course, slows the debris somewhat and thus alters it's orbital path. As additional pieces, such as the Chinese debris, fall into atmosphere bouncing orbits, this greatly complicates tracking and path predictions. The ISS is in a particularly vulnerable position because it is placed right at the outer bounds of Earth's atmosphere. A piece of debris that falls into the atmosphere, several miles before the ISS position, can bounce back up to strike the ISS a glancing shot from below. Thus, any near collision bounce becomes a double threat. So far luck has prevailed, but the debris field is now cause for great concern as an unavoidable collision becomes more and more likely.
Rick
Yesterday the International Space Station (ISS) was ordered to maneuver to avoid collision today with a 4 inch piece of space junk which is said to be a remnant from a Chinese satellite rocket engine traveling at a speed of about 20,000 mph. The shuttle Discovery fired it's thrusters to reorient the ISS out of harm's way. Thankfully, the collision warning was given early enough to allow for evasive maneuvers. During the previous close encounter, with the 5 inch Russian debris, such advance warning was not given. Instead, the astronauts were told to wait in the Soyuz capsule for possible orders to depart from the ISS. Evidently, the path of the Russian debris is much more difficult to predict because it has been bouncing off Earth's atmosphere. Each bounce, of course, slows the debris somewhat and thus alters it's orbital path. As additional pieces, such as the Chinese debris, fall into atmosphere bouncing orbits, this greatly complicates tracking and path predictions. The ISS is in a particularly vulnerable position because it is placed right at the outer bounds of Earth's atmosphere. A piece of debris that falls into the atmosphere, several miles before the ISS position, can bounce back up to strike the ISS a glancing shot from below. Thus, any near collision bounce becomes a double threat. So far luck has prevailed, but the debris field is now cause for great concern as an unavoidable collision becomes more and more likely.
Rick
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