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The rescue of OSCAR-10 (P3-B)<\/h1>\n
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Unfortunately, when OSCAR-10<\/a> was initially launched successfully in 1988, the last stage of the rocket unexpectedly collided with the satellite. This example is to show how IPS helped save the mission.<\/p>\n When OSCAR-10’s 400 bit\/s PSK beacon first automatically reported after launch, the telemetry data was startling:<\/p>\n Something had gone terribly wrong and the condition of the satellite was more than worrying. At this point it was not clear what caused it. It took many more weeks before the real reason was even known. Until then, one was literally groping in the dark.<\/p>\n In order not to lose the battery and the on-board computer, Karl DJ4ZC with his command station in Marburg immediately switched off all unnecessary consumers in the satellite. But that wasn’t enough, the beacon was also switched off to save power and get some charge into the battery.<\/p>\n After a few hours it became apparent that this emergency measure was already having some effect and that the satellite was not lost. But time was still of the essence, the mission was still on the brink of total loss.<\/p>\n In the meantime, Karl analyzed the telemetry and tried to solve the puzzle. It helped that he could execute simple commands in the satellite directly in the interpreter. Individual functions could be changed without recompiling any programs and then uploading them. Because of the flight situation the radio communication was partly also unfavorable.<\/p>\n So Karl was able to find out very quickly that the satellite was turning the wrong way and the flight attitude was completely off. The solar panels were practically no longer illuminated by the sun, instead the sun shone perpendicularly on the head of the satellite.<\/p>\n The P3 satellites have a sophisticated magnetic system for attitude control, consisting of electromagnets in the side arms, which are pulsed by the on-board computer on the basis of the sun and earth sensors in order to exert a force on the axis of rotation together with the earth’s magnetic field and thus tilt the satellite.<\/p>\n In order for the attitude control and sensors to work again, the software or the arithmetic and the coordinate system for the attitude sensors and flight attitude control had to be rewritten.<\/p>\n The night was short and there was not much time for elaborate tests. But IPS is a very secure operating system.<\/p>\n In fact, it seemed to work!! The sensors delivered again meaningful data and already with the next passage through the perigee the solar cells began again to produce noticeably more current.<\/p>\n OSCAR.10 was saved and was available to radio amateurs for many years to come!<\/p>\n It is safe to say that without the flexibility of IPS, such a rescue operation would hardly have been possible, and in doing so, IPS also proved its greatest strength.<\/p>\n <\/p>\n We created a central IPS repository at GitHub<\/a> for all documentation, the original flight software for the 1802 IHU, source code, various ports to Linux and Windows. Until now the files were distributed on different servers. In addition, with every server change, something was always lost, but also the generation and disk changes from ATARI800, to ATARI-ST, ACORN RISC PC, MSDOS, Windows 1-10. A large part we have already recovered from old and private hard disks, but some is still to be processed and sorted. This will be done gradually, unfortunately also very time consuming. Special thanks to Paul Willmott VP9MU, Stacey Mills W4SM, James Miller G3RUH, Peter G\u00fclzow DB2OS and Karl Meinzer DJ4ZC.<\/p>\n Of course this, almost forensic, work is also connected with the hope that the community might find an interest in IPS after all and that the development will be driven further by a larger group.<\/p>\n <\/p>\n Already in 1978 Karl Meinzer, DJ4ZC published the first version of IPS – High Level Programming of Small Systems. In 1997 then appeared the 2nd edition distributed by James Miller G3RUH, and a 3rd edition in 2016, which is also electronically available as a PDF<\/a>.<\/p>\n A 4th edition has now been published in 2019 by Prof. Dr. Karl Meinzer (Author) and Juergen Pintaske (Editor). In response, Mr. Pintaske wrote: “As we prepared, it became apparent how much work has gone into this project IPS – and is little known.”<\/p>\n <\/p>\n\n
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<\/p>\nIPS at GitHub<\/h1>\n
IPS – the book!<\/h1>\n
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