Satgen301 Satellite - Hindsight No 1 by GM4IHJ 31 Dec 94 BID of this msg is SGEN301 Please use this BID if you retransmit this msg How many times does one wish that something had been done differently. Amateur and Commercial satellite builders have made many mistakes in the past , and, it is important, that were possible, these errors should not be repeated. So in a purely constructive sense . Satgens over the next several weeks will report some of these disasters. No criticism is implied of anyone. We can all be wise after the event. Battery Failures - We spend a lot of money putting up satellites, but in the end most of them finish up , still in orbit , in many cases for hundreds of years, but totally silent because of short circuited batteries. Now and again a rare satellite breaks this cycle, because it developes an open circuit battery , which does not short the main power bus, allowing the satellite to continue to function for many more years so long as its solar cells are working. Oscars 6 and 8, and radiosports 2 to 7 inclusive all succumbed to short circuit batteries. Whereas RS1 and Oscar 7 continued to function for years after battery failure. Is it possible that we have missed a trick here. Can we not devise a circuit which breaks the battery connection when the battery short circuits, there by extending the useful life of many of our satellites. Quality Control - In the Nuclear submarine world, no one is allowed to do a job of work , without it being thoroughly checked by an independent test authority. This has not always been the case with satellites Eg Hubble Telescope lenses. Nor is it the case that Amateur satellite builders can escape criticism in this regard. As far as is known , no third party quality control team checked the wiring of the Oscar 10 kick motor. When operated in space the motor was commanded to make a brief burst to alter the satellites perigee height. The motor started firing but continued firing long after it had been told to stop. Indeed it may well have continued firing until fuel was exhausted. As a result of this , the satellite went into a highly dangerous orbit which spent far too long in the Van Allen Radiation belts. There was no fuel left to correct this situation. So quite quickly the heavy radiation bombardment destroyed the usefulness of the satellites onboard computer. There are several possible theories as to why this happened , but all of them suggest that lack of Quality inspection at building may well have contributed to the problem . Certainly there are no grounds what so ever to support one theory offered at the time that the satellite had been damaged in collision with the third stage of the launcher. A collision did occur but there is no reason to connect the collision to the failure to stop the motor firing. More recently , in the case of the Arsene satellite. It appears that its early failure may be attributable to a plug not being fully connected to the appropriate socket. English historians report the fate of the king whose horse lost a shoe nail, and hence lost the shoe, causing the king to lose the battle and his life. Quality Control checking by third party inspectors should surely be mandatory in any enterprise where so much time , effort and money is riding on a package which once sent on its way , can never be returned to the builder for correction of errors and omissions. A big welcome to mode A RS15. Its high orbit it should give lots of DX Thanks to all for seasons greetings. All the best from Scotland for 1995. 73 de John GM4IHJ @ GB7SAN