AMSAT-NA AMSAT News Service

March 21, 2004

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NO-45/Sapphire Update

The NO-45 digipeater remains on. User are requested NOT to use the Bulletin Board. When the Bulletin Board is used it effectively "locks out" ground access to the spacecraft CPU.

Everyone is welcome to use the digipeating/APRS features of Sapphire, callsign KE6QMD, as per the user service agreement located at http://web.usna.navy.mil/~bruninga/pcsat/contract.txt

There will be occasional dropouts caused by the CW beacon, and users are advised to expect extra packet chatter during west coast (USA) passes, as some schools are using Sapphire for operations training.

[ANS thanks Mike, KE6YNJ for the above information]

OSCAR-11 Report 16 March 2004

OSCAR-11 celebrated its 20th birthday on 01 March. After 20 years in orbit, it is still transmitting useful data. To commemorate this event, AMSAT-UK is issuing a special QSL for reports of reception during March. There are special endorsements for hearing the satellite on its birthday, and for mode-S reception. It's still not too late to apply for a QSL, but all reception reports must be received by 07 April. For full details visit the AMSAT-UK website at http://www.uk.amsat.org/

At the present time the satellite is operating in a default mode, transmitting continuous ASCII telemetry on 145.826 MHz, for ten days followed by ten days of silence. However, during March ground control are hoping to reset the timer each time the VHF beacon switches OFF. This should minimize the OFF time, but there may be some gaps in the transmissions. The mode-S beacon is ON continuously.

For the latest news, visit the website http://users.zetnet.co.uk/clivew

During the period 16 February to 15 March 2004 the 145.826 MHz. beacon has been heard transmitting continuous ASCII telemetry from 25 February to 06 March, and from 09 March. If the current ten day cycle continues, the beacon should switch OFF on around 19 March. During this period good signals have been received.

Around 27 February the date in the ASCII telemetry incremented, giving an error of four days. This appears to be a leap year problem, which first occurred in 1992.

The internal temperatures have increased by about 1.5C. They are now 14.6C, 11.8C and 17.8C for battery, telemetry electronics and command decoder, respectively. Solar eclipse predictions indicate that temperatures are expected to increase, reaching a peak in March, a trough in June/July and then increasing until the end of September, when the satellite will encounter continuous sunlight for the remainder of the year. Higher temperatures and greater temperature changes are expected this year, compared to 2003.

The battery voltage observed during daylight passes has decreased. This is because the S-band beacon was switched OFF during the previous reporting period. The reduction in line current causing higher than usual battery voltage. Observations have varied between 13.2 and 13.5 volts, with an average value of 13.35 volts for 25 February to 06 March. From 09 to 15 March the voltage varied from 13.6 to 13.7 with an average value of 13.6 volts.

Spin periods of 344 to 453 seconds have been measured from the magnetometer telemetry. The rotational speed is nominal and variations random. The direction of rotation is normal.

Users of OSCAR-11 should note that the date in the telemetry is now advanced by FOUR days. The time is advanced by 19.5 minutes, and this error is increasing by about one minute per year.

The mode-S beacon on 2401.5 MHz has been heard by Ferrucio IW1AM, Dean AL7CR, Mark CT1JFC/G4MAW, Ken W7KKE, Ferracio & Piero IW1AM/IZ1ERR, Martin G7MRF, Mirek OK2AQK and Bill GM0ICF. Also, many more reports have been submitted to the AMSAT-UK website for the special birthday QSL endorsement. Many thanks for all those reports.

The mode-S beacon is ON continuously, even when the VHF beacon is OFF, nominally transmitting an unmodulated carrier on 2401.5 MHz. There is however a VERY low level of AFSK modulation, (now a constant audio tone), which has been detected on strong signals. Telemetry indicates that the beacon has partially failed, and is delivering half power. This beacon is a useful test source for those testing mode-S converters, as an alternative to OSCAR-40. However the signals are very weak, and there is a lot of Doppler. Users should also note that the polarization of OSCAR-11 is LHC. Even if you can't hear OSCAR-11, your equipment may still be OK for OSCAR-40. Any reports of reception on 2401.5 MHz would be most welcome. Please e-mail g3cwv@amsat.org.

The 435.025 MHz. beacon is normally OFF. It can only be heard on the very rare occasions when the satellite is being commanded by ground control, i.e.. within range of Guildford, UK. When the 435 MHz beacon is transmitting, the 145 MHz beacon is normally OFF. The data transmitted is mainly binary.

The web site contains details about using a soundcard for data capture, and also details about using hardware demodulators. There is software for capturing data, and decoding ASCII telemetry. There is an archive of raw data for analysis, which is continually being expanded, as new data is captured. Originally this was for WOD, but it is now being expanded to include ASCII telemetry. At the present time the telemetry covers 1996 to April 2003. I will add other years as time permits. In parallel there is a news archive which provides an overview of the state of the satellite, at the times when the telemetry was captured.

If anyone out there can provide any data, particularly for the 1984 to 1993 years, this would be most appreciated. Please e-mail me with details. However please DO NOT SEND ANY FILES, before further discussion.

Also included are some audio files, examples of each type of data transmitted by OSCAR-11, each one plays for about ten seconds. There are also examples of mode-S reception. All the audio files are zipped, so that they can be played off-line. These should help listeners identify the various types of data, and give an indication of the signal quality required for successful decoding.

The URL is http://www.users.zetnet.co.uk/clivew/

If you place this bulletin on a terrestrial packet network, please use the bulletin identifier $BID:U2RPT95.CWV, to prevent duplication.

[ANS thanks Clive, G3CWV for the above information]

ARISS Status and Contact Schedule

The ARISS packet uplink is back on 145.99 with a downlink of 145.80. APRS/packet is normally on but usually off for awhile after a school contact. Random voice contacts are rare due to limited time from the 2 man crew.

To provide some insight on how tough it is to schedule contacts, here are some of the constraints the ARISS mentors must work under:
Each Increment is 26 weeks in length.
For the next increment we may not schedule:
1. Anything the first 4 weeks.
2. During EVA weeks (2 EVAs are scheduled for Increment 9)
3. at least 2 weeks prior to the Increment change.
4. no contacts during meal and exercise periods.
5. no contacts during post-sleep and pre sleep (before 0800 UTC and after1930 UTC)

Recent School Contacts

School of Bhac, Scotland
Contact was successful Wednesday 2004-03-17 14:26 UTC telebridge via WH6PN

Congratulations to Mike and the School of Bhac! Thanks to WH6PN for the ARISS telebridge ground station, to KC6ROL acting as MC, and to MCI for the telebridge facilities and webcast.

Upcoming School Contacts

Saltoschool Hanevoet, Eindhoven,NL-5655 CP, direct via PI4EHV
DELTA mission with André Kuipers
TBD 2004-04-24

ESA-ESTEC, Noordwijk, NL-2201, direct via PI9ESA
DELTA mission with André Kuipers
TBD 2004-04-25

Currently the ARISS operations team has a list of over 60 schools that we hope will be able to have a contact during 2004. As the schedule becomes more solidified, we will be letting everyone know. Current plans call for an average of one scheduled school contact per week.

[ANS thanks Charlie, AJ9N and Kenneth, N5VHO for the above information]

Los Alamos and Surrey Satellite Contract for Experiment

Los Alamos National Laboratory and Surrey Satellite Technology Limited (SSTL) have announced a contract agreement for development of an advanced satellite platform for ionospheric and lightning studies.

The British firm, SSTL, will create the satellite platform that will be used to carry the Cibola Flight Experiment payload developed by Los Alamos. The contract with SSTL is valued at USD 11.8 million.

Los Alamos, operated by the University of California for the U.S. National Nuclear Security Administration, is building the Cibola Flight Experiment (CFE), a reconfigurable processor payload intended for a low-Earth orbit system. It will survey portions of the VHF and UHF radio spectra. The experiment uses networks of reprogrammable field programmable gate arrays (FPGAs) to process the received signals for ionospheric and lightning studies. The objective is to detect and measure impulsive events that occur in a complex background.

The experiment will also validate the on-orbit use of commercial, reconfigurable FPGA technology demonstrating several different schemes for the mitigation and correction of "single-event upsets" that would crash most current computer systems.

The U.S. Department of Defense Space Test Program (STP) is including the CFE satellite as part of the STP-1 space flight mission. The STP-1 mission goal is to provide space-flight opportunity for a maximum number of DoD Space Experiments Review Board payloads on a single launch. The DoD Space Test Program is responsible for the integration of seven satellites into a single payload stack and launch of the STP-1 mission. The STP-1 mission is scheduled for launch in 2006 on a medium-class Lockheed-Martin Atlas-V, a U.S. Air Force Evolved Expendable Launch Vehicle (EELV), using the EELV's Secondary Payload Adapter that allows small satellites to be launched as "piggyback" passengers with larger spacecraft.

Timothy Murphy, head of research and development during the selection process in the International, Space and Technology Division at Los Alamos, added "It will be essential that our payload's partners can meet our schedule with a flight-proven satellite platform that we are confident will be flight-ready in time for the EELV launch."

[ANS thanks SSTL for the above information]

Steam Micro-propulsion Demonstrated In-orbit

SSTL has demonstrated in-orbit the use of a steam propulsion system onboard the UK-DMC satellite, launched on 27th September 2003. The novel micro-propulsion experiment used 2.06 grams of water as propellant. This 'green' propellant is non-toxic, non-hazardous to ground operators and results in improved specific impulse over conventional cold gas nitrogen, at a significantly lower cost.

During the first in-orbit firing, the thruster was pre-heated to 200 degrees. Pre-heating ensures that no liquid phase water is ejected, only steam. The spacecraft experienced 3.3 milliNewtons of thrust over a 30 second period.

Designed and built in-house at SSTL, the miniature resistojet, weighing 13 grams, uses just 3 watts of power to heat the propellant, emitting steam through a conventional rocket nozzle to generate thrust. The hotter the propellant, the higher specific impulse performance achieved.

The experiment has demonstrated that:

[ANS thanks SSTL for the above information]

This Week's News in Brief

Weekly Satellite Report

Link to the weekly report on satellite ...

All Satellites
ISS. RS-12. RS-13. RS-15. AO-7. AO-10. UO-11. UO-14. AO-16. LO-19. FO-20. UO-22. KO-23. KO-25. IO-26. AO-27. FO-29. GO-32. SO-33. PO-34. UO-36. AO-40. SO-41. SO-42. NO-44. NO-45. MO-46. AO-49. SO-50


Please send any amateur satellite news or reports to the ANS Editors at ans-editor@amsat.org

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This week's AMSAT News Service bulletins were edited by AMSAT News Service Editor Lee McLamb, KU4OS, ku4os@amsat.org

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