SB SAT @ AMSAT $ANS-014.01 G3IOR RS-15 KEPS HR AMSAT NEWS SERVICE BULLETIN 014.01 FROM AMSAT HQ SILVER SPRING, MD JANUARY 14, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-014.01 G3IOR Keplerian Elements For RS-15 As you many have noted, none of the objects from the RS-15 launch provide a very good match to the actual passes of RS-15 when those Keplerian element sets emanating from NORAD/NASA are placed in your computer. Pat (G3IOR) has been "tweaking" experimentally-derived element sets for RS-15 since it was launched. Here is his latest, which is accurate within about 15 seconds as of 15 January: RS-15 1 99915U 94360.16222500 .00000000 00000-0 13414-4 0 26 2 99915 64.8310 174.9040 0173420 233.4418 0.0000 11.27498800 13 >From his QTH in Norwich, Norfolk, England (JO02PP), Pat has so far managed to work Nebraska, Arizona, New Mexico, Texas, Oregon and California to date, and even Dennis N6DD at 34.038N 117.797W in a mutual one minute window horizon grazer. He reports ery little activity from Asia and Africa so far, but lots of Europeans. [The AMSAT News Service would like to thank G3IOR and W2RS for this bulletin item.] /EX SB SAT @ AMSAT $ANS-014.02 SUNSAT SET FOR JAN '96 LAUNCH HR AMSAT NEWS SERVICE BULLETIN 014.02 FROM AMSAT HQ SILVER SPRING, MD JANUARY 14, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-014.02 SUNSAT: A Micro Satellite Under Construction In South Africa SUNSAT is a 60kg, 45 by 45 by 62 cm micro satellite being designed, built and tested by twenty Two M.Eng. students at the Electronic Systems Labor- atory in the Department of Electrical and Electronic Engineering at Stellenbosch University. Detailed design started in January 1992, led by Computer and Control System lecturers. SUNSAT was originally designed for a sun-synchronous-type orbit on the Ariane 4 Helios mission, which is ideal for the main imaging payload. However, when launch costs became prohibitive, alternatives were sought. NASA scientists have learned a great deal about the earth by detailed studies of the magnetic field and the gravitational field, and have arranged for the Danish Oersted microsatellite to be launched as a secondary payload on a USAF Delta II from Vandenberg Air Force Base on the P91-1 Argos mission in January 1996. NASA and Stellenbosch have now agreed to carry SUNSAT into the same orbit instead of a counterweight for Oersted. In exchange for the launch, Sunsat will carry a precision GPS receiver and a set of Laser retro-reflectors. These will enable NASA to study fine orbital perturbations for gravity field recovery, and for cross verification of GPS and NASA's laser tracking network.The orbit will be the same as Oersted, namely polar, 400 by 840 KM. The equatorial crossing will initially be approximately 15:00 UTC, and drift an hour earlier every seventy days. SUNSAT is a complex microsatellite. Its developers expect they will not have time and manpower to utilize all its possibilities, and hope that other amateurs and universities will become interested in using it once it is fully commissioned. Since this is their first satellite, they recognize this may take many months to get right. The Amateur Radio communications payload comprises a packet radio service, a 2M band "parrot" speech transponder, and a Mode-S transponder. The use of an imaging system necessitates attitude stabilization. Coarse attitude stabilization will be by a gravity gradient boom and by mag- netorqueing and is improved by small reaction wheels during imaging. Continuous spacecraft attitude sensing is provided by magnetometers, sun sensors, visible wavelength horizon sensors, and a star sensor provide 1 miliradian accuracy when imaging from the sun-synchronous orbit. The average power of 25W enables images of South Africa and elsewhere to be taken on a daily basis for real time downlinking. Availability of excellent linear Silicon CCD sensors able to operate in the visual and near-IR band led to a 3-color sensor system with bands similar to SPOT 4 and LANDSAT 6. These permit "biomass" production monitoring, which is of continuing interest in a "water-short" country like South Africa, for example. A linear CCD sensor with 3456 pixels of 10.7 microns spacing was also chosen. The optical assembly is mounted in a tube which can be rotated forward or rearward for stereo images. The communications payload provides duplicated synthesized transmitters and receivers for the 2M and 70CM Amateur Radio bands and nearby frequencies. A 23CM receiver will operate as a fast uplink, or be coupled to the S-band downlink transmitter to provide a straight-through transponder. The high resolution data will be transmitted in real time via the S-Band downlink to reception stations at Stellenbosch and Johannesburg. Small- area images stored in the RAM disk can be down-linked at much lower rates. For example, a 40 kbyte image covering a 4 km x 4 km area can be downloaded at 9600 baud in about 100 seconds. The SUNSAT team plans to be able to supply such images on request to amateurs once the satellite is fully operational. At 800 KM altitude, a 5 deg elevation footprint has a diameter of 5,080 KM and which spans 45 deg in longitude. Radio range varies from 800 to 2,800 KM compared to the geostationary range of 36,000 KM. Data communication with 10 watts or lower powered transmitters and a dipole antennas is practical, permitting data interchange with low cost terrestrial transceivers. Since large quantities of data can be stored in the sat- llite, global data transfer is possible. AX25 data protocols will be used to ensure error-free operation. The 5 Watt EIRP S-band downlink will produce a 14.4 dB S/N ratio in a 40 MHz bandwidth at 2000 KM slant range for a 4.5 m diameter parabolic dish that has a 100 degree Kelvin receiving station which is current what is being planned for Stellenbosch. By adding an L-band receiver and appropriate switching, a transponder capable of 1 MByte/s with 2M diameter ground stations can be implemented. Application of the system for Amateur Radio gateway service is possible. The Amateur Radio payload definition was approved at the SA-AMSAT Spacecon 91 Conference. Store and forward digital packet radio will be provided, including 1200 baud AFSK for compatibility with terrestrial equipment common in South Africa. To provide sufficient uplink channels, one of the 2M band receivers has four IF sections displaced in 25 kHz steps, and connected to 1200 baud modems. Three 9600 baud modems compatible with the G3RUH standard are carried, and can be switched to various receivers and trans- mitters. Both the 2M up/down and 2M up/70CM down options will be included, together with full bulletin board facilities. The AMSAT Pacsat Standard Protocols can be supported. The 2M and 70CM downlinks can be switched to 10 Watts output, producing a 0.5 uV signal (50 Ohm) at 435 MHz and 1.5 uV signal at 145 MHz with 0dBi receive antenna at full range. This power level will be used over critical areas to provide signal to noise ratios approaching 15dB for easy reception. At other times the power will be reduced. A 2M "parrot" mode repeater is intended especially for Novice category users (under the age of 16). Up-linked speech will be digitally stored and re- transmitted on the same frequency. Novice school users will thus hear the re-transmission and know that they are getting through. The need to learn and apply operating protocols will definitely be experienced! Stay tuned to the AMSAT News Service (ANS) bulletins as more information about SUNSAT will published as the launch date of January '96 approaches for SUNSAT. [The AMSAT News Service would like to thank Henry Chamberlain (ZS1AAZ) for this bulletin item.] /EX SB SAT @ AMSAT $ANS-014.03 AMSAT OPS NET SCHEDULE HR AMSAT NEWS SERVICE BULLETIN 014.03 FROM AMSAT HQ SILVER SPRING, MD JANUARY 14, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-014.03 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 21-Jan-95 19:00 NA, SA, Eu, Af Sat 28-JAN-95 23:00 NA, SA Sun 05-FEB-95 02:00 NA, JA, NZ, EAus 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-014.04 WEEKLY OSCAR STATUS REPORTS HR AMSAT NEWS SERVICE BULLETIN 014.04 FROM AMSAT HQ SILVER SPRING, MD JANUARY 14, 1995 TO ALL RADIO AMATEURS BT BID: $ANS-014.04 Weekly OSCAR Status Reports: 14-JAN-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] FO-20: FO-20 is in the analog mode permanently and thus those that enjoy working a "non-digital" mode will like FO-20. Many FO-20 users are complaining that they are hearing themselves calling CQ on the downlink but there are no stations responding. [KF0QS] MIR: The cosmonauts aboard MIR ask that those who use its packet BBS to please delete their mail messages after reading them. They have a limited memory TNC and with all the use it has been getting lately, the 22 KBytes fills up quickly! Also remember that the MIR PBBS can only accept one con- nection at a time. All other stations must STOP calling the MIR PBBS while a station is actively using the MIR PBBS. Calling the Mir PBBS, while some- one else is logged in and trying to transfer data is poor operating practice and could be considered "intentional interference". [WF1F & KD2DB] KO-25: WA4SCA reports that the KITSAT-OSCAR-25 Bulletin Board System is open and working. [WA4SCA] 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 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