At 07:42 10/09/1999 , Aldo Loup wrote: Could it had been generated by a >Titan 4 rocket (or its payload) launched on that day?. Or by an Ariane >42 (or payload INSAT 2E) launched a few days earlier?. Were phenomena >like this one observed before?. Aldo, The Titan4/IUS launch left the payload in a geostationary transfer orbit because the IUS second stage fired while still attached to the IUS first stage, according to information posted to Seesat-L by Philip Chien. So it seems unlikely that the reported observations are that launch. But if they are I hope that the reports have got thru to the satellite controllers. As it was a spy satellite launch, no information is publicly available except that 4 components are catalogued. As Ron Lee has already implied, solid rocket ( like IUS ) are different from liquid fuel firings. In a lot of solis rocket fuel mixtures, 10 to 30 percent of the fuel is aluminium, which results in aluminium oxide as a combustion product. This is more visible than the the result of liuid fuel combustion Bill Bradfield, a retired Rocket Engineer and Comet Hunter, ( 17), observed such a cloud of al2O3 quite a few years ago, incedental to a session of comet hunting. It was the injection into geostationary orbit of a DSP satellite, deployed from the space shuttle some 6 hours before. Tony Beresford Cospar 8597 34.96S, 138.6333E)