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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:black'>Hi BARS members,<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'>The SpaceX Falcon Heavy rocket launch is scheduled for 6:35 PM tonight! </span><span style='color:#2A2A2A'>The launch will be broadcast live online via </span><a href="https://www.youtube.com/user/spacexchannel/"><span style='color:#5C00D8;text-decoration:none'>SpaceX’s YouTube channel</span></a><span style='color:#2A2A2A'>.</span><span style='color:black'><o:p></o:p></span></p><p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:.5in;line-height:15.4pt;background:#FCFCFF'><span style='font-family:"Georgia",serif;color:#141414'>In August 2017, a SpaceX Falcon 9 high altitude rocket, launched from Vandenberg, generated a gigantic circular <i>Shock Acoustic Wave</i> (SAW) in the ionosphere covering an area four times greater than California. The rocket was vertically boosting a lightweight satellite payload to a mission altitude of about 450 miles (720 km) above the earth. That altitude is more than most Low Earth Orbit (LEO) satellites, and a <a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017SW001738" target="_blank"><span style='color:#176093'>team of scientists</span></a> tracked the rocket's effects as it poked a hole in the ionosphere about 5 minutes after launch. <br><br>High altitude rocket launches can temporarily affect ionospheric propagation. They are called a<i>nthropogenic space weather events</i>. Such changes in the ionosphere could affect HF propagation reflection or perturb GPS positioning accuracy. <br><br><a href="https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017SW001738" target="_blank"><span style='color:#176093'>Scientists studying the event</span></a> recorded SAWs emanating outward for 20 minutes, at about 1500 Miles Per Hour (2400 kph) . It was the largest rocket</span><span style='font-family:"Times New Roman",serif;color:#141414'>‐</span><span style='font-family:"Georgia",serif;color:#141414'>induced circular SAW on record, about 900 miles (1500 km) in diameter. The rocket's exhaust plume also created a large scale ionospheric plasma hole, which eventually closed back up. <a href="https://eos.org/research-spotlights/understanding-the-effects-of-anthropogenic-space-weather" target="_blank"><span style='color:#176093'>Read more about it on Earth & Space Science News.</span></a><o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='color:black'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='color:black'>From:<o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><span style='color:black'><a href="https://forums.qrz.com/index.php?threads/rocket-launch-affected-ionosphere-propagation.609587/">https://forums.qrz.com/index.php?threads/rocket-launch-affected-ionosphere-propagation.609587/</a><o:p></o:p></span></p><p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:black'>I missed the last launch and always wondered if I could detect any changes in propagation due to the launch. Tonight we’ll have a chance to see. This will be only the second flight for the world’s most powerful rocket now in operation, so if any rocket can impact propagation, this one can.<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:black'>Might be an interesting topic for the Net tonight?<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'>73,<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'>Jon Turner<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'>AC1EV<o:p></o:p></span></p></div></body></html>