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The Loaded Uzi

        foreach $dataitem (@$array)
        {
            ......
            elsif($index == 15)
            {
              my $mean_motion = $xmldocument->createElement("mean-motion");
              $orbital_element->appendChild($mean_motion);
              $mean_motion->appendChild($xmldocument->createTextNode($dataitem));
            }
            elsif($index == 16)
            {
               # revolution-at-epoch
               # first-derivative-of-mean-motion
            }
            $index++;
         }