Satgen 441 Cheaper by the Dozen by GM4IHJ (BID SGEN441) 6 Sept 97 Orbiting of the first 22 satellites of the Iridium mobile phone network ( 3 Delta II launches of 5 sats plus 1 Proton launch of 7 sats), to be followed by another Proton launch this month, is setting an interesting pattern. Presently each new launch fills part of a new orbit plane separated 32.5 degrees from the previous plane. This allows testing between sats in the same orbit plane and, testing between sats in different orbit planes. But it does leave some slightly awkward numbers to fill in each planes 11 sat complement , if it is to be done economically with the least number of launches. The problem is that it is easy to adjust sats from the same launch ,in the same orbit plane, but placing sats from the same launch in different orbit planes is much more difficult to achieve cheaply. Sats with different mean anomalies is easy . Sats with different right ascensions, is difficult and expensive. So how will this affect some of the much bigger constellations of satellites being launched for say the Teledesic fleet? Teledesic are presently running a very colourful Internet graphic show of their orbit proposals at http://www.teledesic.com/visualizations/visual.html The graphics are great ( and useful educationally), but they do not say how they will get the sats there. There seem to be two problems. 1. is the obvious crowding at certain latitudes ( no surprise with 21 orbit planes each plane containing 40 sats plus 4 spares = 924 sats). Problem 2 is how and by whom will this lot be launched. These numbers may be reduced in practice , but it will be a big task, however many satellites make up the final fleet. In the past the biggest multiple launches have been the Russian Cosmos military store and forward comsats. These have been launched 7 or 8 at a time , ie a payload total of around 1600 Kg going to 1400 kms altitude in a high inclination orbit. Teledesic will also be launching to high inclination with each satellite weighing perhaps 800 Kg. So a very big launch vehicle will be required if large numbers are to be launched on the same rocket to about 700 kms altitude. Available launches might be Ariane 5 or Titan 4, or perhaps the proposed Russian Angara vehicle. This Russian rocket might be able to launch up to 20 satellites at a time into the same orbit plane. With Ariane and Titan managing somewhat smaller numbers. It is going to be interesting to see if Teledesic can get enough launches in the next few years to launch this enormous fleet. To add to the fun Globalstar ( 48 sats), is another contender in this rush to LEO orbit, and they are already reported to be booking launchers. Meanwhile, Lewis the recently launched American NASA remote sensing satellite was in trouble as August ended, Power supply problems were indicated. Originally this was thought to be due to satellite spinning and thereby getting poor insolation of the solar panels. If the sat gets back to a good sun angle this month it may be possible to save it. But if recovery is delayed further the satellite will probably reenter the atmosphere and burn up . Lets hope Lockheed have more luck with the 25 Oct launch of LMLV-2 + Lunar Prospector.