SB ALL @ AMSAT $ANS-226.01 Report Smooth AO-13 Operations HR AMSAT NEWS SERVICE BULLETIN 226.01 FROM WA2LQQ WARWICK, NY August 13, 1988 TO ALL RADIO AMATEURS BT Operations on AMSAT OSCAR 13 continued at a brisk pace this week as the spacecraft enters its second month in orbit. An operating schedule which will be in use until late September has been announced and AMSAT-DL workers continue their efforts to get the RUDAK packet system running. AO-13 operations could be characterized as "smooth" with patterns of use now emerging even while new users clamber aboard. Mode B continues to be the most popular with Mode J close behind. Mode L use is growing with every orbit as more users try out their new Mode L equipment. Mode J use will be restricted according to AMSAT-DL. As the average Mode L experience level increases, higher satisfaction levels are evolving. As marginal operating conditions are being avoided and optimum ones are being exploited, perceptions of required uplink power levels are falling. Several stations are regularly active running ten watts and relatively short yagi antennas. Consistent performance does, however, require more uplink power. Various activities are being planned for AO-13. Among these are various nets, Techno-Sports and communications services. According to K.O. Learner, K9PVW, AMSAT's Space Education Net (SEN) will debut in September possibly over the Labor Day weekend. September 3 is being considered. SEN may on occasion employ SSTV as part of its programming. The intent is to provide a meeting ground for those interested in advancing space education using AO-13 as a primary vehicle. Studies which will lead to re-commencement of the ZRO-Test in about a month are under way as well. Watch for an announcement regarding times and frequencies for the first runs on AO-13. An information packet on the ZRO-Test is being updated and will be available soon. AMSAT membership is growing nicely based on the success of AO-13. AMSAT HQ says hundreds of new and renewing members have signed up in recent weeks. Many more are expected to join as an expression of satisfaction with AO-13 operations and the special events planned. Many special events will offer special placement for AMSAT members all satellite users are reminded. So, 3 weeks after commencement of AO-13 communications operations, 2 months after the Phase 3C launch, 3 years after the Phase 3C project began in earnest, 5 years after AO-10 was launched, 8 years after Phase 3A was lost and 12 years after the Phase 3 program began, operations on our first near-Molniya orbit OSCAR are settling in to an atmosphere of familiarity and satisfaction. Users are becoming familiar with its capabilities and are, quite apparently, deeply satisfied and grateful to the organizations and individuals who made it all possible. /EX SB ALL @ AMSAT $ANS-226.02 AMSAT-DL Seeks AO-13 RUDAK Fix HR AMSAT NEWS SERVICE BULLETIN 226.02 FROM WA2LQQ WARWICK, NY August 13, 1988 TO ALL RADIO AMATEURS BT AMSAT-DL workers report some progress in diagnosing the problem which has affected RUDAK operations. In tests performed this past week they have gathered further evidence the problem is temperature-related. RUDAK is a packet digipeater developed and built by AMSAT-DL workers in Munich. It is one of four transponders aboard AO-13. Engineers are currently unable to upload software to the RUDAK because a PROM device is apparently running too cold. Current efforts at a "fix" include heating the RUDAK by activating adjacent modules such as the Liquid Ignition Unit (LIU). RUDAK prognosis is unclear at present although this week's developments have offered the first glimmer of optimism. Officially, AMSAT-DL spokesman will say only the RUDAK group is hard at work attempting to get the software loaded. "RUDAK worked perfectly before launch in Kourou" and an "identical system has been running for nearly 2 years on top of a water tower in Munich, so it's unclear what has happened after launch," according to the spokesman. Testing of RUDAK will continue for an indeterminate period according to AMSAT-DL. /EX SB ALL @ AMSAT $ANS-226.03 AMSAT Looking At Mode S Plans HR AMSAT NEWS SERVICE BULLETIN 226.03 FROM WA2LQQ WARWICK, NY August 13, 1988 TO ALL RADIO AMATEURS BT AMSAT officials are considering when AO-13 Mode S will be activated. Mode S, a single channel, hard-limited, FM transponder has an uplink at 70 cm and a downlink at 13 cm (2.4 GHz). Because it has a 70 cm uplink, Mode S must be scheduled concurrent with Mode B which also has a 70 cm uplink. Because of the very narrow beam of the 13 cm Mode S downlink, Mode S must be scheduled for near-apogee when squint angles will be small enough to allow good Mode L reception. A 1.4 meter (4.6 foot) dish will provide the minimum recommended 28 dBi antenna gain for receiving Mode S. A system noise figure of not worse than 3 dB is believed adequate for Mode S. The Mode S transponder was built by AMSAT-NA by a Colorado team under the leadership of AMSAT veteran Bill McCaa, K0RZ. /EX SB ALL @ AMSAT $ANS-226.04 AO-13 Element Sets and Sked HR AMSAT NEWS SERVICE BULLETIN 226.04 FROM WA2LQQ WARWICK, NY August 13, 1988 TO ALL RADIO AMATEURS BT NASA-supplied element sets for AO-13 through at least bulletin 15 (August 9) are in error and should be discarded. You can detect faulty data for AO-13 if the inclination is given as about 9.9 degrees. The actual inclination is about 57 degrees. The current NASA AO-13 prediction bulletin is based on pre-kick motor firing observations and is thus invalid. The best element set now available, MH7-12, continues to provide excellent tracking results and should be used with confidence until further notice. NASA officials at the Goddard Space Flight Center say they are aware of the problem. The computer that generates the NASA element sets, they say, is simply using early observations and projecting them forward. The problem will be cleared in a week they say. Here is the current AO-13 operating schedule. It will remain valid until September 21 and may be deviated from for engineering tests. Revised Operating Schedule: V3.0 6Aug88 +---------------------------------------------------------------+ | Mode | From | Thru | Remarks | Duration | | |(Inclus)| (Inclus)| | MA Minutes| |========|========|=========|==================================== | Off | MA 241 | MA 002 | Solar eclipse window | 18 48.3 | | Mode B | MA 003 | MA 099 | | 97 260.2 | | Mode L | MA 100 | MA 180 | Mode JL optional | 81 217.3 | | Mode B | MA 181 | MA 220 | | 40 107.3 | | Mode B | MA 221 | MA 240 | With omni antennas | 20 53.6 | |--------+--------+---------+----------------------+------------+ | Mode S | | | Commence September(?)| | | RUDAK | | | Testing; ops pending | | +--------------------------------------------------+------------| The current attitude is approximately BLON=180, BLAT=0. /EX SB ALL @ AMSAT $ANS-226.05 "Do Svidanyia" RS-5 and 7? HR AMSAT NEWS SERVICE BULLETIN 226.05 FROM WA2LQQ WARWICK, NY August 13, 1988 TO ALL RADIO AMATEURS BT According to the operators at the Soviet Union's Radio Sputnik control center near Moscow, RS3A, the old RS satellites, RS-5 and RS-7, are definitely out of operation now. RS3A has gradually lost control over these last two active RS satellites of the RS-3 to RS-8 series. They are convinced that the batteries in RS-5 and RS-7 are dead so no new activities can be expected from these satellites. RS-3 through RS-8 were launched "en masse" December 17, 1981. There have been conflicting reports, however, as to whether either or both these satellites has been heard since late July. /EX SB ALL @ AMSAT $ANS-226.06 Shuttle Engine Tests "Perfect" HR AMSAT NEWS SERVICE BULLETIN 226.06 FROM WA2LQQ WARWICK, NY August 13, 1988 TO ALL RADIO AMATEURS BT (Story by KC2ZF and NW2T) The U.S. Space Shuttle Discovery's three main engines awakened this week for a roaring 22 seconds announcing the closing phases of a long return trek to shuttle operations. Discovery's flight, now slated for late September or early October, will be the first post-Challenger flight. The performance of last Wednesday's test was best summed up by Astronaut Bob Crippen, mission management team chairman, who said simply: "We really had a super test." Consuming more than 1,000 pounds of fuel per second, the engines roared to life at 7:30 am Eastern time Wednesday, August 10, quickly throttled up to 100 %, sending clouds of dust and orange flame into the Florida skies. Engine shut down started at 19 seconds after the first ignition. NASA teams had placed 732 instruments throughout the orbiter to make detailed measurements of all systems during the test. Before the exercise, launch director Bob Sieck said, "We'll test the hardware and the software and the people. We want to demonstrate the readiness of the total system for flight." Also checked during the test were modifications to high pressure turbo-pumps, valve actuators, electronic controllers and other engine systems. Although Crippen dismissed it as not a "significant problem", there was data indicating unexpected behavior in a system used to flush an area of the shuttle with nitrogen gas. NASA engineers do not expect it to delay the flight. The firing had been delayed five times in the past two weeks, mostly by failures in ground support equipment and not problems in the shuttle itself. The most recent problem, a faulty sensor/valve unit, was replaced at a cost of over $75,000. Two of the three engines on the Discovery are new, with the third having three space flights under its restraining bolts. Together, the liquid oxygen/hydrogen engines produce a power output equal to twenty three Hoover dams. Technicians now plan to cut a hole in an area of the shuttle adjacent to a leaky fitting on the Orbital Maneuvering System (OMS) pod. Although this procedure has never before been attempted, it is thought to have a good chance of success. The unorthodox procedure is being undertaken to fix a small leak on the OMS which, had it been accomplished in the prescribed manner, would have required Discovery to be rolled back from the launch pad to the vertical assembly building for rework. That operation could have delayed launch by up to two months NASA said. Another major test of the shuttle system will come later this week when the Solid Rocket Booster must pass it's fifth and final propulsion test before flight certification is made. The final test is scheduled for August 18th. Based on last Wednesday's successful main engine firing, NASA Administrator James Fletcher said in an interview, "We have a shot at the end of September". However, many observers believe October is more realistic for planning Discovery's next flight. /EX SB ALL @ AMSAT $ANS-226.07 Soviet Cosmonaut Dies HR AMSAT NEWS SERVICE BULLETIN 226.07 FROM WA2LQQ WARWICK, NY August 13, 1988 TO ALL RADIO AMATEURS BT (Story by KC2ZF) Veteran Soviet Cosmonaut Anatoly Levchenko died of a brain tumor this past week, the Soviet news agency TASS reported. Levchenko, 47, had been operated on by Soviet doctors but to no avail. Levchenko, an experienced flight crew member with several missions to his credit, flew most recently to the Soviet Mir Space Station on December 21, 1987 for an 8 day stay. It is believed that he, along with Cosmonaut Igor Volk, was one of the primary pilots in training for the first manned flight of the new Soviet Shuttle. There is speculation that his death may further delay the apparently trouble-plagued program. Soviet space officials have conceded in private they are having trouble developing the space shuttle but have provided few details. Mr. Levchenko was born in the Ukraine about 435 miles south of Moscow, was an air force test pilot and joined a team of cosmonauts testing space vehicles in 1981, according to TASS /EX SB ALL @ AMSAT $ANS-226.08 SEUs Affect TDRSS and OSCARs HR AMSAT NEWS SERVICE BULLETIN 226.08 FROM WA2LQQ WARWICK, NY August 13, 1988 TO ALL RADIO AMATEURS BT According to a report in the authoritative journal "Aviation Week and Space Technology," the Tracking and Data Relay Satellite System (TRDSS) is being upset about twice per day by a phenomenon called "Single Event Upset" or SEU. The result is introduction of memory errors which affect spacecraft operations and data integrity. If an SEU occurs at a critical time, space officials say, it could spell disaster for vital space missions. The cause of the SEUs is radiation from various sources. The solar wind and cosmic rays are prime sources of the damaging ionizing radiation. The radiation corrupts data stored as minute electric charges in the satellite's computer's Random Access Memory or RAM. The affected memory can be reloaded and, although data will be lost, there appears to be no permanent damage to the RAM which has shown SEU susceptibility. Officials at Pasadena's Jet Propulsion Laboratory (JPL) are concerned, however, that if an SEU disables TDRSS during a critical phase of an important space mission, failure of that mission could result. One of TDRSS's missions is the relay of telemetry and command/control data to and from satellites in low earth orbits as well as deep-space missions. Some of the spacecraft using TDRSS, such as interplanetary probes, are highly or mostly autonomous. Failure of TDRSS could cause these missions grave damage. Additionally, the U.S. Shuttle relies on TDRSS for much of its orbit to stay in contact with NASA facilities. A terrestrial network is used as a "gap-filler" and backup. During past Shuttle missions TDRSS has carried the bulk of scientific data originating in probes and instruments on the Shuttle at rates in the range of hundreds of megabits per second. A TDRSS SEU during Shuttle operations could result in lost data. AMSAT OSCAR 10's Integrated Housekeeping Unit (IHU) showed many SEUs during its early years of operation. The special error-correcting code used, however, prevented any serious operational problems from arising. Eventually, however, the NMOS RAM of AO-10's IHU succumbed to total accumulated dose of radiation and suffered a "hard" failure rather than the "soft" failure of the SEU type. A "hard" failure condition is much more serious than the SEUs now affecting TDRSS. A "soft" failure can be corrected by merely re-writing data to the affected cell. An SEU can be caused by the passage of a charged particle through a RAM cell. If the charge is large enough or the cell dimensions are small enough, the passage of the charge can obliterate the data stored in that cell making a "1" a "0" or vice versa. AMSAT OSCAR 13's memory, on the other hand, is highly resistant to both SEU and total dose so there is no concern regarding its IHU. The University of Surrey, in an on-going program, is using UoSAT OSCAR 11 as an SEU probe. Surrey says every Wednesday morning, UO-11's DSR memory bank is downloaded via the UHF downlink (435.025 MHz) at 4800 baud. It contains a test pattern, loaded the 18th of July. Due to cosmic radiation, errors will be introduced in the memory chips. Regular downloading of Bank A will give a good idea of the impact of radiation on the chips. Tests will continue over the next few months. Information on how to participate in the tests may be obtained directly from the University of Surrey. /EX SB ALL @ AMSAT $ANS-226.09 Short Bursts HR AMSAT NEWS SERVICE BULLETIN 226.09 FROM WA2LQQ WARWICK, NY August 13, 1988 TO ALL RADIO AMATEURS BT Did you know that, on average, AO-13 equator crossing longitudes repeat (to within +/- 5 degrees) every 18 days or so? This, and other facts about AO-13's orbit appear in ASR #181. Amateur Satellite Report is AMSAT's bi-weekly newsletter and is sent to all members regularly. In addition to the above "factoid" it also contains important information and photographs available nowhere else. AMSAT membership has its advantages. AMSAT-NA's all-OSCAR frequency charts are in production and will be mailed to all qualified donors by month's end. AMSAT OSCAR 10 is out of service until further notice. It's the hibernation season for this veteran bird. JARL says it will soon begin work on another flight model of JAS-1 with an eye towards launching a second OSCAR after a long hiatus since the launch of JAS-1 (FO-12). Efforts with JAS-1B will focus on improving the satellite's tight power budget and antenna directivity in order to obtain a flatter pattern for better performance. Here is the FO-12 operating schedule. Mode From (UTC) ---------------- JA Aug 13 0630 D 14 0536 JD 18 0603 DI 19 0712 JD 20 0415 DI 21 0523 JD 25 0348 DI 26 0457 JD 27 0606 D 28 0511 JA 30 0120 D Aug 31 0228 JD = Digital mode JA = Analog mode D = All systems off DI = Systems off except CPU and memory The transponders will be off at other times. The actual operating schedule may change due to unexpected situations such as variations in available power. Mode JA Beacon: 435.795 MHz. Mode JD Beacon: 435.910 MHz. /EX