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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626">Hello Everyone,<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626">The attached spreadsheet has the glossary terms vetted against the existing SANA glossary terms. The terms from the Green books are in Columns B & C. If SANA has an existing
definition that is different from those definition in the Green Book(s), it can be found in Column G. Based on these two sources as well as comments received, Column H hosts suggested updates to SANA, either for new terms to be added or to existing terms.
<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626">ACTION to ALL: Please provide your comments or concurrence on these terms on Column H.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626">I request your thoughts on two terms: Nutation, Precession.
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626">Based on several references (Kaplan (pp 53-54), Wertz (493-498), Markley, Julie’s inputs to SANA for Attitude/Spacecraft Conventions, etc), nutation is the angular momentum
vector offset from spin/principle axis introduced by geometric offsets (not external torques); precession is the change in the angular momentum vector due to external torques.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626">In the ADM, the distinction between nutation and precession is not clear:</span>
<o:p></o:p></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:10.0pt;font-family:Helvetica;color:#548235;mso-style-textfill-fill-color:#548235;mso-style-textfill-fill-alpha:100.0%">From ADM Corrigendum:<o:p></o:p></span></p>
<p class="MsoNormal" style="margin-left:.5in"><span style="font-size:10.0pt;font-family:Helvetica;color:#548235;mso-style-textfill-fill-color:#548235;mso-style-textfill-fill-alpha:100.0%">As in some attitude dynamics references, in this document the term ‘nutation’
is used to mean the motion of the spin axis of a body about an inertial axis. In many other references this motion is called ‘precession’.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626">The definitions in the Green Book Glossary(ies) are inconsistent with the cited references or unclear.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626">ACTION: I’d like your inputs – particularly from Alain! – on a resolution to add these terms correctly to SANA, and whether the ADM corrigendum text needs to be updated
to be consistent with the definitions.<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626">Thank you all!<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626"><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626">Kind Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:Helvetica;color:#262626">Cheryl<o:p></o:p></span></p>
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<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Lucida Grande",sans-serif;color:black">---<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Lucida Grande",sans-serif;color:black">Cheryl Gramling<br>
GSFC/Sr. Navigation Systems Engineer<br>
<a href="cheryl.j.gramling@nasa.gov"><span style="color:#0563C1">cheryl.j.gramling@nasa.gov</span></a><br>
[O] 301-286-8002</span><span style="color:black"><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Lucida Grande",sans-serif;color:black">[C] 240-328-5517</span><span style="font-size:9.0pt;font-family:"Lucida Grande",sans-serif;color:black"><o:p></o:p></span></p>
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