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<p class="MsoNormal"><span style="font-size:11.0pt">As promised, here is the CNES/NASA/CSSI/Iridium paper regarding the concept of relaxing the Pc threshold in certain cases where, in the unhappy circumstance that a collision were to occur, it would be unlikely
to produce a large quantity of debris fragments. This was the original paper (attachment #1). A subsequent version is provided (attachment #2), as well as a paper seeking to validate the mass and area deteriminations.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Within attachment #2, I have highlighted the relevant text in yellow. Ultimately, this is a very simple approach to implement (that they advocate):<o:p></o:p></span></p>
<ol style="margin-top:0in" start="1" type="1">
<li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1"><span style="font-size:11.0pt">Compute collision probability;<o:p></o:p></span></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1"><span style="font-size:11.0pt">Determine the orbital regime;<o:p></o:p></span></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1"><span style="font-size:11.0pt">If LEO, then determine (using the simple NASA Std Breakup Model) if we’d anticipate that this collision would generate more than 200 fragments;<o:p></o:p></span></li><li class="MsoListParagraph" style="margin-left:0in;mso-list:l0 level1 lfo1"><span style="font-size:11.0pt">If it does *<b>not</b>* exceed 200 fragments, then downgrade the Pc value by one order of magnitude (otherwise, use the Pc value “as is”.<o:p></o:p></span></li></ol>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">The only potential area of complexity with this method involves the estimation of space object cross-sectional area and object mass, but I don’t believe that the CDM needs to contain normative content for
that aspect; while the papers propose some methods on how one might be able to reverse engineer area and mass values, I believe that existing, available databases such as ESA’s DISCOS DB (which contains space object dimensions and mass) could be a recommended
input for the CDM assessment process.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Dan<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
<div>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Segoe UI",sans-serif;color:#1F497D">__________________________<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Dan Oltrogge</span><span style="font-size:11.0pt"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Director, Center for Space Standards and Innovation (CSSI) and Integrated Operations<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">COMSPOC Corporation<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt">Voice: 719-482-4552 </span>
<span style="font-size:13.5pt">҉</span><span style="font-size:11.0pt"> E-mail: </span>
<a href="mailto:oltrogge@comspoc.com"><span style="font-size:11.0pt;color:blue">oltrogge@comspoc.com</span></a><span style="font-size:11.0pt"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt">-----Original Appointment-----<br>
<b>From:</b> Berry, David S (US 3920) <david.s.berry@jpl.nasa.gov> <br>
<b>Sent:</b> Wednesday, October 14, 2020 6:28 PM<br>
<b>To:</b> Berry, David S (US 3920); moims-nav-exec@mailman.ccsds.org<br>
<b>Subject:</b> CCSDS Nav WG Fall Meeting #4<br>
<b>When:</b> Monday, November 9, 2020 6:00 AM-8:00 AM (UTC-08:00) Pacific Time (US & Canada).<br>
<b>Where:</b> JPL Webex<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><span style="font-family:Courier"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier">UTC 1400-1600<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier"><o:p> </o:p></span></p>
<p class="MsoNormal"><a href="https://jpl.webex.com/meet/dberry"><span style="font-family:Courier">https://jpl.webex.com/meet/dberry</span></a><span style="font-family:Courier">
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier">See </span><a href="https://cwe.ccsds.org/moims/docs/MOIMS-NAV/Meeting%20Materials/2020/Fall/navwg-agenda-fall-202010.pdf"><span style="font-family:Courier">https://cwe.ccsds.org/moims/docs/MOIMS-NAV/Meeting%20Materials/2020/Fall/navwg-agenda-fall-202010.pdf</span></a><span style="font-family:Courier">
for detailed agenda (it could be provided in this email, but is potentially subject to change)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier;color:black">Local Times</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier;color:black">===========</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier">6<span style="color:black">:00 AM 0</span>6<span style="color:black">00: Los Angeles</span></span><span style="color:black"><o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-family:Courier;color:black">11:00 PM 2300: Daejon</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-family:Courier"><o:p> </o:p></span></p>
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