SB ALL @ AMSAT $ANS-198.01 Full AO-13 Operations Imminent HR AMSAT NEWS SERVICE BULLETIN 198.01 FROM WA2LQQ WARWICK, NY July 16, 1988 TO ALL RADIO AMATEURS BT With AO-13 now approaching its operational attitude, the beginning of the AO-13 satellite communications era is at hand. After years of delays caused by various launcher problems, the newest OSCAR is now safely ensconced in its final orbit. It reached its final orbital milestone shortly after the second and final kick motor firing on July 6. Since the final kick motor firing, several additional steps have been taken towards checking out the various systems and configuring the spacecraft for general operations. Immediately after firing the kick motor, an assessment of the spacecraft attitude and condition was made. The spacecraft apparently suffered no ill effects of the 5.5 minute burn and post-burn analysis of the orbit suggests the spacecraft attitude was nearly perfect at the instant of motor firing on July 6. On July 11, the RUDAK CPU was switched on for the first in-orbit check. A complete verification of the 52 kbyte RUDAK memory was successfully performed according to AMSAT-DL. However, the RUDAK beacon activation (435 MHz downlink) must await proper orientation of the spacecraft. A description of RUDAK appears in two installments in the July and August QST satellite communications column. By Saturday, July 16, the satellite had been successfully spun down to 29 rpm which is close to the desired angular velocity. As has been discussed in previous bulletins, orbital determination has proceeded extremely well with AO-13. The process has become a source of considerable pride with those who participated. According to G3RUH, tracking data based on various sources and processes have converged nicely. First, the estimated element set based on assumed motor performance and burn time; second, the element sets derived by active AMSAT ranging methods and third, the radar skin track-derived element sets have all converged to a remarkable degree says G3RUH. The satellite has been assigned catalog number 19216 and is being tracked by NORAD radar facilities. Here is the NORAD radar skin track element set for AO-13. Satellite: oscar-13 Catalog number: 19216 Epoch time: 88193.90000000 Mon Jul 11 21:36:00.0 1988 UTC Element set: mh7-12 Inclination: 57.6540 deg RA of node: 247.5380 deg Eccentricity: 0.6538919 Arg of perigee: 187.2210 deg Mean anomaly: 357.2170 deg Mean motion: 2.09697960 rev/day Decay rate: 0 rev/day^2 Epoch Rev: 57 Semi major axis: 25783.070 km Anom period: 686.701959 min Apogee: 36264.507 km Perigee: 2545.826 km Ref perigee: 3844.90368652 Mon Jul 11 21:41:18.515 1988 UTC /EX SB ALL @ AMSAT $ANS-198.02 Initial AO-13 Operating Sked HR AMSAT NEWS SERVICE BULLETIN 198.02 FROM WA2LQQ WARWICK, NY July 16, 1988 TO ALL RADIO AMATEURS BT AO-13 is expected to be available for general communications use before the end of July. If procedures continue to go well, AO-13 could be on-line in the next week. However, an exact turnover date has not been forecast due to the experimental nature of the processes involved. Best advice is to watch these bulletins and advice on AO-13's beacon channels. The beacon frequencies are: Mode B: GB: 145.812 MHz EB 145.985 MHz Mode L GB: 435.651 MHz EB 435.677 MHz All that remains to be done before turning on AO-13's transponders is to re-orient the satellite to a suitable operational attitude. With work on bringing AO-13 to full operational readiness going so well, initial plans for opening the satellite to operation have been announced. Here is the preliminary AO-13 operating schedule. The exact numbers are subject to last-minute adjustment. Watch your bulletins for updates: Mode From Thru Duration MA Minutes ================================================================ Off MA 225 MA 29 61 163.7 Mode B MA 30 MA 97 68 182.5 Mode L MA 98 MA 157 (daily) 60 161.0 Mode JL MA 98 MA 157 (weekends only) 60 161.0 Mode B MA 158 MA 224 67 179.8 Mode S (Mode-S operations will commence when sun angles permit; likely in September RUDAK Concurrent with Mode L Each MA (Mean Anomaly) unit equals 2.6824 minutes. This is calculated by taking the period of the orbit (686.70 minutes) and dividing it into 256 equal parts. The MA clock resets to zero at perigee. Half way through the orbit, the MA clock equals 128 at apogee. /EX SB ALL @ AMSAT $ANS-198.03 AO-13 Sends CW, RTTY & PSK Tlm HR AMSAT NEWS SERVICE BULLETIN 198.03 FROM WA2LQQ WARWICK, NY July 16, 1988 TO ALL RADIO AMATEURS BT Like a physician's stethoscope, AO-13's telemetry stream is a monitor of its heartbeat. To the careful listener, the telemetry stream on any of the beacons is an opportunity to see and understand deeply the condition of the spacecraft. In future, moreover, bulletins of interest and importance to the satellite user will be broadcast over the beacons. To those equipped to monitor the telemetry, AO-13 will be an open book. AO-13 telemetry is transmitted in three forms: PSK (phase shift keyed); RTTY; CW. The RTTY uses FSK (frequency shift keyed) tones spaced 170 Hz at a signaling rate of 50 baud. RTTY telemetry is sent at 15 and 45 minutes past the hour. CW telemetry is sent at 10 wpm at 0 and 30 minutes past the hour. PSK telemetry is sent at other times at 400 baud. The Mode B General Beacon is at 145.812 MHz. Telemetry reception in many areas has been hampered by FM users many of whom are unaware 145.800 to 146.000 MHz is, by general agreement, a sanctuary for weak signal, satellite operations. Sixty four channels of telemetry are sent in PSK. The first 60 of these are sent in RTTY as well. Occasionally the RTTY telemetry will appear to be sending a series of 3-letter groups usually beginning with a Q. This is simply a 3-character numeric telemetry value for which the "figs shift" RTTY command has been missed by your receiver. Inserting a "figs shift" will correct this anomaly. A more thorough look at AO-13 telemetry is presented in ASR #179 now in the mails. ASR is an AMSAT membership service. To inquire about membership, call 301-589-6062 or write AMSAT, P.O. Box 27, Washington, DC, 20044. /EX SB ALL @ AMSAT $ANS-198.04 Short Bursts HR AMSAT NEWS SERVICE BULLETIN 198.04 FROM WA2LQQ WARWICK, NY July 16, 1988 TO ALL RADIO AMATEURS BT With AO-13 going operational any day, AMSAT has launched a major fund-raising campaign to re-vitalize its depleted treasury for important future projects. Generous donations to AMSAT are urgently needed now if AMSAT is to continue to serve your needs. Please respond positively to this appeal. You help is needed now. AMSAT has issued a Call For Papers for its Annual Space Symposium. Papers on topics relevant to the Amateur Space Program are solicited. Deadline for submission is September 10, 1988. The Symposium will be held in Atlanta this year on November 11-13. (This is a correction to last week's bulletin.) This is a preliminary announcement only. Details to follow ASAP. Mail abstracts and/or papers to AMSAT, P.O. Box 27, Washington DC, 20044 A new and possibly significant delay has hit the U.S. Space Shuttle program. A leak has been discovered in the Orbital Maneuvering System (OMS). The repairs could require removing the Discovery from the pad thus incurring a major delay. At the time the problem was discovered last week, NASA had been saying the launch was scheduled for early September. Here is the current AO-10 operating schedule: Through July 31: Mode B MA 25 to MA 235 August 1 - August 15: Mode B MA 30 to MA 240 The satellite will be unavailable for use beginning August 16 because of predicted insufficient solar illumination and reduced battery charge. If "FMing" of signals occur sooner that August 15, DO NOT USE AO-10 please. As always, please use minimum power required for communications. Listen to your nets for later updates, or to AMSAT OSCAR 13 beacons beginning in late July for any changes to this schedule. Here is the FO-12 operating schedule. Mode From (UTC) ---------------- JA Jul 16 1328 D 17 1235 JD 20 1356 DI 21 1301 JD 23 1141 DI 24 1020 JD 26 1033 DI 27 1141 JD 30 1100 DI Jul 31 1006 JA Aug 02 1020 D 03 1128 JA 06 0845 D 07 0751 JA 11 0617 D 12 0724 JA 13 0630 D 14 0536 JD Aug 18 0603 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. /EX