Satgen 644 GetBack and Relaunch by GM4IHJ (BID SGEN644 ) 2001-07-28 Several correspondents ask whether Amsats present problems are typical of the whole satellite scene, or , unique to amateur operations. A brief summary ( from a very large list ) of professional and university classics, may provide an answer. 1. The satellite needed foreign travelling wave tubes. These could be purchased with space proven power supplies from the TWT manufacturers. The builders fitted locally manufactured power supplies, which failed after a month in space. 2. The first two launches from one academic source failed to respond to orders soon after launch. They were recovered when radio amateurs used powerful radio telescope antennas to find the satellites , in one case by receiving the satellites onboard receiver local oscillator signal. 3. A satellite 5 years in gestation, went into orbit with a loose antenna plug. 5 years wasted. 4. A new rocket used a stabilization platform from a previously successful less powerful rocket. The extra thrust caused the platform to hit the stops. Mission terminated at 1000ft. 5. A satellite designed to monitor Jupiters natural radio signal at HF 15 to 45 MHz. Had a receiver which only tuned up to about 25 MHz. It rarely saw Jupiter directly from its low earth orbit. But it could see Jupiter for about 70% of the time through the earths atmosphere. Unfortunately it could not receive the signal above 25 MHz which penetrated the earth atmosphere and got through to the satellite. All lower frequency Jupiter signals were blocked by the ionosphere. 6. The classic failure of original design was the ECHO balloon satellite. Easy to launch. Then pumped up in space. It provided a superb, large, passive reflecting surface. Unfortunately the enormous drag of the thin atmosphere on the very large surface area and light weight craft, brought it down in orbit so quickly, it needed new keplerian elements every two days of its very short life, before its fiery end. 7. Some superb designs work extremely well, in space. But are simply out of date before they are launched . Both the British and the French launched very high quality hipowered TV satellites. They were restricted to 3 channels and needed a new TV format receiver . Unfortunately, advances in receiver LNB front end technology meant much lower power could have been used, and no one wanted to pay for their expensive new mode TV receivers. Because simple 16 to 24 channel satellites with ordinary PAL reception proved to be all that the public wanted. 8. Last but not least. Pity unfortunate NASA. They have a very high rate of success because they stick to well established designs. But the mirror of the Hubble Space Telescope was made for NASA by a well known telescope maker. NASA put it into a perfect orbit, only to find that the telescope would not focus.