On Sat, 11 Dec 1999, Daniel Deak wrote: > According to AviationWeek & Space Technology, the Russian ocean > surveillance satellite, Cosmos 2347, was commanded to self-destruct > in orbit on Nov. 22. The explosion left more than 130 pieces of debris > in a 230 x 410 km orbit inclined 65 degrees. This part of the Av Week story is monumental garbage. The Russians have not revealed why these EORSATs disintegrate in orbit, but the problem is most likely propulsion-related. When the satellites started to fly they would usually disintegrate in orbit and the best theory is that it related to residual propellant in the spacecraft's tanks. After some time in orbit the residual propellant develops enough pressure to cause a partial disintegration of the satellite. There is nothing intentional about the disintegrations. In the mid-1980s the Russians started to reduce the perigee of the satellites at the end of operations, thus ensuring that the satellites would re-enter the atmosphere before the propellant pressure caused a debris event. In the last few years two satellites have remained operational for so long that they suffered disintegration after having their orbits lowered but before re-entry took place. The re-entry of Cosmos 2347 marks the demise of the EORSAT programme: the two-stage Tsyklon-M launch facilities at Baikonur were closed down around a year ago and the launch team was disbanded. One wonders how many three-stage Tsyklons are still available for launch from Plesetsk: I did hear that there were only around six available a couple of years ago. Phillip Clark --------------------------------------------------------------------------- Phillip S Clark 22 Winterbourne Close Molniya Space Consultancy Hastings Compiler/Publisher, Worldwide Satellite Launches E Sussex TN34 1XG U.K. Specialist in "space archeology" - the older and more obscure the more interesting it is ! --------------------------------------------------------------------------- ----------------------------------------------------------------- Unsubscribe from SeeSat-L by sending a message with 'unsubscribe' in the SUBJECT to SeeSat-L-request@lists.satellite.eu.org http://www2.satellite.eu.org/seesat/seesatindex.html