HR AMSAT NEWS SERVICE BULLETIN 063.01 FROM AMSAT HQ SILVER SPRING, MD MARCH 4, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-063.01 UNAMSAT-1 PREPARED FOR LAUNCH Last week's ANS carried a message from Shlomo, 4X1AS regarding the Israeli TECHSAT satellite built at the TECHNION to be launched March 28 on a Russian launcher from Plesetsk. This note is to provide further information concerning the other amateur satellite to be carried on this launch, UNAMSAT-1. This satellite was built in at the Universidad Nacional Autonoma de Mexico (UNAM) in Mexico City. UNAMSAT-1 is similar to the six previous AMSAT Microsats (AO-16, WEBERSAT, DOVE, LUSAT, ITAMSAT and EYESAT) and is a cube 25 cm on a side weighing about 10 kg. As was the case with all previous AMSAT Microsats (except DOVE), the satellite downlink is 1200 baud PSK in the 70 cm band. Each of the Microsats has consisted of 5 stacked modules, with four of them being nearly identical (2M uplink receiver, Battery Charge Regulator, computer and 70 cm downlink transmitter, all interconnected with a 20cm long 4800 baud local area network). In all 7 Microsats, the 5th module has been reserved for a special experiment of the group that built the satellite -- this 5th module has sometimes been called the TSFR ("This Space For Rent"). The UNAMSAT-1 TSFR is a very unique experiment. It consists of a ~100 watt radar transmitter and receiver operating at ~41 MHz. This radar employs pulses a few msec long to obtain echoes from the ionization trail left behind meteors as they burn up in the earth's atmosphere. The echoes will be digitized at a fast rate. If the onboard software detects an echo, the raw A/D samples will be downlinked for detailed spectrum analysis on the ground to determine meteor velocities and trajectories. The goal is to search for meteors that have velocities greater than the ~70 km/sec solar system escape velocity, indicating that they originated outside our solar system. The ~41MHz radar is licensed by the Mexican authorities according according to the ITU frequency allocations tables. The UNAM organization responsible for UNAMSAT is called Programa Universitario de Investigacion y Desarrollo Espacial (PUIDE). Longtime AMSAT member David Liberman, XE1TU is responsible for the development of PUIDE and UNAMSAT. The effort involved many graduate students, faculty and staff at UNAM. UNAMSAT-1 was built totally in Mexico. AMSAT-NA volunteers offered assistance when it was needed, including WD0E, NK6K, W3GEY, WD4FAB, N4TPY and W3IWI. In addition to the meteor radar experiment, UNAMSAT-1 has all the "PACSAT" store-and-forward capabilities of the other Microsats (except DOVE). The exact divvy of time between the radar experiment and amateur packet radio communications will be determined as the mission progresses. XE1TU and his students are very busy at this time. They depart for Moscow (en route to Plesetsk) next week. After the launch, they will return to Moscow where initial spacecraft checkout will be done from an amateur station located at the Moscow Aviation Institute (MAI); MAI was responsible for the ISHKRA amateur satellites. They will then return home to Mexico in early April. All are certain to look forward to hearing their stories about launching from the arctic Plesetsk site in temperatures of -20 degrees. Tom Clark W3IWI comments that he looks on UNAMSAT-1 with the pride of a "godfather"! ANS thanks Tom Clark W3IWI for the information used in the preparation of this bulletin. /EX HR AMSAT NEWS SERVICE BULLETIN 063.02 FROM AMSAT HQ SILVER SPRING, MD MARCH 4, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-063.02 Long Duration SAREX Mission In Orbit The Space Shuttle Endeavour (STS-67) made a spectacular liftoff from the Kennedy Space Center at 06:38 UTC March 2 initiating what promises to be the longest space shuttle mission to date. The launch was delayed approximately 1 minute from its planned liftoff time due to some questions regarding temperatures of the flash evaporator system. The 7 astronauts on-board Endeavour expect to conduct hundreds of ultraviolet astronomy observations during the planned 16 day mission using the ASTRO-2 observatory, a cluster of three ultraviolet telescopes mounted on the ESA designed Instrument Pointing System. Also on-board the Space Shuttle Endeavour is the Shuttle Amateur Radio Experiment (SAREX). Six of the seven Endeavour astronauts have their ham radio license. These include avid AMSAT supporter Ron Parise, WA4SIR, Commander Steve Oswald, KB5YSR, Pilot Bill Gregory, KC5MGA, Mission Specialist Tammy Jernigan, KC5MGF, Mission Specialist Wendy Lawrence, KC5KII and Payload Specialist Sam Durrance, N3TQA. SAREX is being flown in configuration C on this mission: voice and packet. A record 26 schools from around the globe will participate in SAREX with a scheduled contact with the astronauts. Several more will be listening in to the school student's question and answer session with the astronauts. SAREX operations were initiated approximately 24 hours into the flight of Endeavour. Shuttle commander Steve Oswald KB5YSR reported at 22 hours 58 minutes, mission elapsed time that he had a good checkout with the W5RRR ground station at the club station at The Johnson Space Center in Houston. At first the shuttle crew is trying to solve a problem with the modem and fax machine used to receive updates from the ground, and capcom Marc Garneau quipped that "maybe they should send up the Execute Packages (daily mail) via SAREX." ANS thanks Frank Bauer, KA3HDO and the SAREX Working Group and Philip Chien KC4YER for this information. /EX HR AMSAT NEWS SERVICE BULLETIN 063.03 FROM AMSAT HQ SILVER SPRING, MD MARCH 4, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-063.03 CALL FOR PAPERS For its 1995 AMSAT Annual Meeting and Space Symposium, will return to Orlando, Florida this year. Again for 1995, the Orlando Airport Holiday Inn will be the site for the gathering. Although the meeting is scheduled for October 6, 7 and 8, it is not too soon to start thinking about presenting a paper at this year's Symposium. The Chairman for Papers this year is Bob Walker N4CU. Please conteact him if you can honor us with your knowledge on a subject approproate to amateur satellites. Bob can be reached at n4cu@amsat.org. ANS thanks Bob Walker N4CU for this buiiliten information. /EX HR AMSAT NEWS SERVICE BULLETIN 063.04 FROM AMSAT HQ SILVER SPRING, MD MARCH 4, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-063.04 G4ULS Provides An In-depth Look At Effects Of Eclipses On RS-15: Part I This note follows G3IOR's recent reports about the proportion of time per orbit which RS-15 spends in eclipse, the variation of that proportion over a period, and the consequent effect on operating voltages in the satellite. One of the main findings was that intermittent function of transponder and beacon came after eclipse lasting 15 minutes, full operation returning immediately after re-entry into sunlight. Individual operators will be concerned, not so much with the overall proportion of the orbit spent in eclipse, but with where and when it occurs during the orbit and, if within range, whether it is deep enough to affect operations. The effect will vary considerably according to location. This study is based on a latitude of 52 degree North and a longitude of 2 degrees East encompasing a sequence of 7 or 8 passes in a 24-hour period of which 4 or 5 can have a duration of 30 or 31 minutes. The orbit is not sun-synchronous -- the Right Ascension of the Acending Node (RAAN) shifts slowly at about -1.6 degrees per day and the pass sequence changes slowly in time accordingly. The orbit is also eccentric with a perigee of 1882 kms and an apogee of 2164 KM. The Argument of Perigee precesses by -0.18 degrees per day. Eclipse of a satellite can be explained by considering 2 angles, ES and SSE. ES is half the angle subtended by the earth as seen from the satellite. SSE is the angle formed by lines from Sun to satellite and from satellite to the center of the earth. Eclipse occurs when SSE is lees than ES. ES, being dependent on satellite's height is nearly constant for low earth orbiters. For RS-15 it is 49 degrees at apogee and 48 degrees at perigee. SSE will vary seasonally with the shift of the sun between the solstices. This shift, with the pass sequence changes, gives rise to the eclipse situation. The sun's shift is paramount as a comparison between operations in the two hemispheres on a given day shows. The period from 23-FEB-95 to 22-FEB-96 has been examined and findings constructed around passes including 10 minutes or more of eclipse. This equates to one-third of the duration of major passes and allows for the chance of intermittent operation being observed on those passes, a minority, which start in eclipse. In the summary below, "clear" means passes completely clear of any eclipse, the majority, or with 9 minutes or less of eclipse. The main findings, given the overall and obvious conclusion that night sequences are those most at risk. The periods are: (a) The period 23 Feb - 13 March is clear of eclipses. (b) 14 March - 7 April reaches a maximum of 3 passes a day with eclipse with a maximum of 17 minutes in an eclipse. (c) 8 April - 11 August is clear of eclipses. (d) 12 Aug -20 Aug shows a single pass per sequence only, with 10 minutes of eclipse (e) 21 Aug -20 Oct is clear of eclipses. (f) From 21 October eclipsed passes rise from 2 per sequence with a maximum of 16 minutes eclipse to 4 and even 5 per sequence with maxima of up to 28 minutes eclipse. Decline starts about 25 December. By 12 Jan 1996 there are 2 passes in the sequence with a maximum of 16 minutes of eclipse in a pass. (g) 20 Jan - 22 Feb 1996 is clear of eclipses. It would have been preferable to have produced a detailed calendar of the above which stems from use of N4HY excellent QUIKTRAK program. Regardless of volume considerations, the output available fron the program required considerable notation, etc. A lot of time will be needed for tabulation! Output for Tokyo and Melbourne was also taken to examine differences between locations. One might have expected to discern a cyclical pattern but, apart from the obvious predominance of eclipse in the darker months, this has not been the case in looking at a single year. The reason is that a change in RAAN of -1.618 deg. per day would bring a repeat pass sequence of ground track approximately every 222.5 days approximately because of other small changes in orbital parameters over time. In fact, the pass sequence of 23-FEB-95 is virtually repeated, at a different period within the day on 27 September (216 days later). But at that date the sun's position is quite different. Combination of an annual cycle with one of about 216 days suggests a three-yearly repeated coincidence. Empirically, the pass sequence for 23-FEB-95 is seen as repeated, to within 10 minutes and a degree or two of AZ/EL, by that of 7-MAR-98. Thus, a moving three-year projection proides a reasonable forecasting guide. A further bulletin will follow with a table illustrating the point more fully. The broad presentation above is intended merely as advanced warning. The consequences of charge/discharge cycles on batteries which are not holding charge could be serious. Attempts to use the satellite in adverse conditions or the use of too much power in uplink at any time could aggravate the situation. The regular and constant heavy battery charge/discharge cycle in successive orbits during eclipse periods will undoubtedly shorten battery life and produce shorter time of operation during dark hours in the long term. [The AMSAT News Service (ANS) would like to thank Vin Thompson, (G4ULS) for this bulletin item. For further questions or comments, Vin can be reached at his packet radio address of G4ULS@GB7BBS.#28.GBR.EU] /EX /EX SB SAT @ AMSAT $ANS-063.05 WEEKLY OSCAR STATUS REPORTS HR AMSAT NEWS SERVICE BULLETIN 063.05 FROM AMSAT HQ SILVER SPRING, MD MARCH 4, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-063.05 Weekly OSCAR Status Reports: 04-MAR-95 AO-13: Current Transponder Operating Schedule: The Mode Schedule from 20-FEB-95 until 22-MAY-95 will be: Mode-B : MA 0 to MA 190 |Omnis : MA 250 to MA 140 Mode-BS : MA 190 to MA 218 | Mode-S : MA 218 to MA 220 |<- S beacon only Mode-S : MA 220 to MA 230 |<- S transponder; B trsp. is OFF Mode-B : MA 230 to MA 256 | Blon/Blat 230/0 Note: The Mode-B beacon is ON during the Mode-S transponder operations only. Please do NOT uplink to the B transponder during Mode S only, as it interferes with Mode-S operations. [G3RUH/DB2OS/VK5AGR] AO-13: VK2EYI reports that he had an excellent day on AO-13 on 03-MAR-95, and just a message to let AO-13 users know that VU2RM has been very on active over the last few days with a very good strong signal and also a number of JAs have been present on the downlink. [VK2EYI] The AMSAT NEWS Service (ANS) NEEDS YOUR HELP! The ANS looking for volunteers 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