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Re: Delfi-C3 status update 30 April 2008 08:00 UTC




Hi All
a good pass of delfi at 1150 utc got 50 packets decoded the beacon was switching on and off every 60secs or so starting at 1155-30 secs approx finally switched off at1200-20secs or there aboutsRegards Robert G8ATE > Date: Wed, 30 Apr 2008 10:16:58 +0200> From: wjubbels@gmail.com> To: amsat-bb@amsat.org> CC: rascal@delfic3.nl> Subject: [amsat-bb] Delfi-C3 status update 30 April 2008 08:00 UTC> > Hi all,> > Delfi-C3 is in orbit and healthy, despite some minor issues, please find a> status update below:> > 1. Telemetry indicates that all solar panels and antennas have deployed> properly> > 2. Telemetry indicates nominal values for all housekeeping values> > 3. We have already obtained payload data, and have been able to generate IV> curves of the Thin Film Solar Cell experiment, note that those uring> RASCAL can view the IV curves by clicking Options-->show IV curves in> RASCAL.> > 4. The spacecraft is operating in science mode, we have had one orbit in> emergency mode, which was most probably due to a databus issue> > 5. Up till now we have received 7000+ (!) frames from amateurs using RASCAL> around the globe, amazing, thank you all so much!!> > 6. We have verified command uplink functionality yesterday, and were able to> command the spacecraft today on the low elevation (4.9max) pass over our GS> at 0737UTC> > 7. The spacecraft has decided to consistently use the backup radio on> 145.930MHz for its telemetry downlink, we were able to request a full> on-board database dump while in range of our groundstation yesterday and> analysis of the database confirms this. We currently have a good> understanding why this is the case. We will try to switch downlinks to the> primary radio on 145.870MHz during the next good pass over our GS, so> amateurs in Western Europe might want to check that frequency also and might> experience intermittent telemetry while we are commanding. Note that we> suspect that the TX frequency could be 1 to 2 kHz lower on this radio, so> tuning around slowly is the best strategy.> > 8. The spacecr
aft seems to have an issue with the downlink TX switching off> into the orbit, which is the reason while Delfi-C3 has not been heard on> most descending passes over VK/ZL, we think we have a good understanding of> why it is. The TX itself is fine, but it switches off automatically when it> does not get data from the OBC for a certain amount of time. We are working> on resolving this issue. This also happened during the pass over our GS at> 0737 UTC but we were able to command it back on. For those in Western Europe> we would like to ask to keep tracking Delfi-C3 even if you can not hear it> at first, as we will try to turn the TX back on as soon as we notice that it> has been turned off.> > 9. Thank you all for your observations on the spin rate, these are really> helpful! We currently think that the spacecraft is tumbling with approx> 10deg/second, which corresponds to a 36 second period. Since the s/c> downlink antenna is almost truely circular, polarization sense can change> from RHCP to LHCP completely depending on s/c orientation, we use circular> antennas on our GS as well, and when we switch to the opposite polarizaiton> sense the signal is wiped out completely, switching back gives solid copy> with strong sigs.> > 10. NORAD object E #32787 seems to match best> > > thanks for all your observations and efforts so far!> > 73 on behalf of the Delfi-C3 team,> > Wouter Jan Ubbels> _______________________________________________> Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author.> Not an AMSAT-NA member? Join now to support the amateur satellite program!> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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