Hi All I heard Delfi-c3 for about a minute ,only ,at about 0916utc this morning on 145.930+/- doppler last evening it also switched off halfway through its obit just after 2000utc using a pointable 6el horiz quad and doppler tuned ft8476 in io92jp Regards 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 spacecraft 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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