SB SAT @ AMSAT $ANS-035.01 ANS APOLOGY HR AMSAT NEWS SERVICE BULLETIN 035.01 FROM AMSAT HQ SILVER SPRING, MD FEBUARY 4, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-035.01 APOLOGY ANS Bulletin 035.04 released January 28 mentioned, in a negative manner, a specific design feature of the "R. J. Myers" S Band dish. This, or any other reference to the adequacy or inadequacy of any commercial product should not have appeared in ANS, and AMSAT-NA Management takes full responsibility for this slip-up. ANS bulletins are the official voice of the Radio Amateur Satellite Corporation (AMSAT) and thus should confine themselves to factual material, not personal opinions. ANS should be contrasted with AMSAT-BB which is a vehicle for free exchange of ideas and information between individuals and, unless otherwise specifically stated, nothing that appears on BB represents the official position of AMSAT-NA. As the to Bob Myers Communications S Band dish, AMSAT-NA takes no position on it, one way or the other, however, Bill Tynan (W3XO) AMSAT-NA President was quoted as saying, "I can say personally, that in the many notes I have seen posted on AMSAT-BB, I have never seen another comment that the Bob Myers Communications dish does not perform well. This opinion has also been reflected in a number of personal conversations I have had with various satellite operators who use this dish." ANS apologizes to Bob Myers Communications for any harm this bulletin might have done to the organization. /EX SB SAT @ AMSAT $ANS-035.02 UO-22 EXPERIENCES A SEU HR AMSAT NEWS SERVICE BULLETIN 035.02 FROM AMSAT HQ SILVER SPRING, MD FEBUARY 4, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-035.02 UO-22 Suffers A Single Event Upset (SEU) Between 22:00 and 24:00 UTC on 29-JAN-95 during an orbit where UoSAT-OSCAR-22 passed through the South Atlantic Anomaly (SAA), the spacecraft suffered a crash of its OBC-186. What was first thought to be a straightforward software crash proved to be much more serious. Examination of Very Large Scale Integrated (VLSI) telemetry during morning passes on 30-JAN-95 revealed that the current drain of the OBC-186 was running about 3 times the normal value. Following a number of short real-time tests and observations, ground controllers took the decision to power down the OBC-186, RAMDISK and associated hardware for several hours before attempting further diagnostic activities. The OBC-186 was left in the powered down state for a period of roughly 18 hours before ground controllers resumed recovery attempts. In the meantime, VLSI telemetry was left on the downlink and a number of experiments were switched off under telecommand as a power saving measure. During the first morning pass over Europe on 31-JAN-95 ground controllers began a systematic power up procedure of the OBC 186 and all associated hardware. Observations were very promising as current drain for the OBC-186 had returned to normal and the bootloader was observed on the downlink indicating nominal operation of the flight computer hardware. On the following pass over Europe, UoSAT engineers and ground controllers uploaded a series of diagnostic software into the spacecraft to test both the Error Detecting And Correction (EDAC) memory and the RAMDISK. All tests returned positive results with no errors reported in either system. The diagnostic software for the RAMDISK was left running for the next orbit which would pass through the SAA after going LOS at the UoSAT command and control center. On the final morning pass the test software was observed to still be operating as expected reporting no errors and the decision was taken to begin the software reload process. This process was completed during the evening passes on 31-JAN-5 over Europe. While the recovery of UO-22 is good news indeed, it is an unfortunate necessity that the RAMDISK had to be powered down as part of the recovery process. Unlike a straightforward software crash this anomaly resulted in the loss of all files contained aboard the UO-22 file server. Controllers have decided to limit uploading of files to the spacecraft for the next 24 hour period as the final stages of the recovery process unfold. After the spacecraft is deemed to be stable the store-and-forward system will once again be opened for use by users world-wide. We appreciate everyone's cooperation while we work the remaining operational issues. [The AMSAT News Service (ANS) would like to thank Doug Loughmiller (G0SYX), UoSAT Spacecraft Operations Manager, for this bulletin item.] /EX SB SAT @ AMSAT $ANS-035.03 AMSAT OPS NET SCHEDULE HR AMSAT NEWS SERVICE BULLETIN 035.03 FROM AMSAT HQ SILVER SPRING, MD FEBUARY 4, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-035.03 AMSAT Operations Net Schedule To take full advantage of the upcoming "good" phase on AO-13, the following AMSAT Operations Net Schedule will be in place. The primary downlink frequency for all Ops. Nets will be 145.950 MHz. In case a QSO is in progress on that frequency at net time, 145.955 MHz will be used as an alternate. Net control for all of these nets will be Keith (W5IU); however, anyone is welcome to serve as an alternate. Reports on all phases of OSCAR operations are welcome. Guest speakers on special topics will be scheduled as availability permits. Day Date Time Coverage ________________________________________________________ Sat 11-FEB-95 18:00 NA, SA, WEu, Af Sat 18-FEB-95 22:00 NA, SA Note: All times are in UTC; therefore, Sun. dates are actually Sat. evening in USA. Times do not conflict with ZRO Tests. Thanks - Keith, W5IU, AMSAT VP of Operations /EX SB SAT @ AMSAT $ANS-035.04 WEEKLY OSCAR STATUS REPORTS HR AMSAT NEWS SERVICE BULLETIN 035.04 FROM AMSAT HQ SILVER SPRING, MD FEBUARY 4, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-035.04 Weekly OSCAR Status Reports: 04-FEB-95 AO-13: Current Transponder Operating Schedule: The Mode Schedule from 19-DEC-94 until 20-FEB-95 will be: Mode-B : MA 0 to MA 100 |Omnis : MA 230 to MA 25 Mode-BS : MA 100 to MA 130 | Mode-S : MA 130 to MA 132 |<- S beacon only Mode-S : MA 132 to MA 155 |<- S transponder; B trsp. is OFF Mode-S : MA 155 to MA 160 |<- S beacon only Mode-BS : MA 160 to MA 180 | Blon/Blat 180/0 Mode-B : MA 180 to MA 256 | Move to attitude 230/0, Feb 20 [G3RUH/DB2OS/VK5AGR] AO-27: W9ODI reported that AO-27 was on last weekend, Jan 28-29. [W8GUS & W9ODI] IO-26: Ground controllers IV2VOO and IK2OYD have loaded and succesfully ran the the latest version of IHTX code. This code allows for a scheduled OFF of the main trasmitter to preserve battery power and increase TX power during the mostly used parts of the orbit. WOD dumps are underway to analiyze the new power trends and the BBS code upload will begin next week if all is OK. [I2KBD] The AMSAT NEWS Service (ANS) NEEDS YOUR HELP! The ANS looking for volun- teers to contribute weekly OSCAR status reports. If you have a favorite OSCAR which you work on a regular basis and would like to contribute to this weekly bulletin, please send your observations to WD0HHU at his CompuServe address of 70524,2272, on INTERNET at wd0hhu@amsat.org, or to his local packet BBS in the Denver, CO area, WD0HHU @ N0QCU. Also, if you find that the current set of orbital elements are not generating the correct AOS/LOS times at your QTH, PLEASE INCLUDE THAT INFORMATION AS WELL. The information you provide will be of value to all OSCAR enthusiasts. /EX