SSME would be pretty easy to ID at long range due to the high UV levels.<br /><br />If you look at a plume and don't see that, you have narrowed down the search to some variety of solid rocket propellant, LOX and a hydrocarbon, or hydrazine and nitrogen tetroxide.<br /><br />Somebody help me here if I missed one.<br /><br />Seems like looking for carbon and aluminum in the exhaust would be pretty definitive without getting to far into the classified world. (no carbon in hydrazine and N2O2 and no aluminum in anything but solid fuel.<br /><br />SS1 has a weird fuel mix, but hopefully your travel agent would help you sort out those launches.<br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>