INCREASING SOLAR ACTIVITY CLEANS UP SAT-DEBRIS: Earth’s atmosphere has been puffing up in response to increasing levels of UV radiation from sunspots. This is good news for satellite operators, because a puffed up atmosphere helps clean up low-Earth orbit. “The number of cataloged debris in Earth orbit actually decreased during 2011,” reports Nick Johnson in NASA’s Orbital Debris Quarterlynewsletter. “[The figure below] illustrates how the rate of debris reentries from the Fengyun-1C anti-satellite test of January 2007 increased during the past year.”

“Even though only 6% of the total 3218 cataloged debris from the ill-advised engagement had reentered by the end of 2011, half of these debris fell out of orbit in the past 12 months,” he points out. “Likewise, many debris from the 2009 accidental collision of Cosmos 2251 and Iridium 33 are accelerating their departure from Earth orbit. In the absence of a new major satellite breakup, the overall orbital debris population should continue to decrease during 2012 and 2013.”

fr/spaceweather.com