[amsat-bb] Re: ARISSat daylightpower recovery time

andy thomas andythomasmail at yahoo.co.uk
Sat Sep 24 11:22:17 PDT 2011

My observations last weekend show that MET matches the satellite entering sunlight:
18 September
calculated Time into sun: 1004 utc
Time of obs (announcement): 1023 utc
Voice announced MET: 19
calculated Time into sun: 1136 utc
Time of obs: 1158 utc
Voice announced MET: 21
maybe the voice tlm MET isn't accurate either!
howver I calculated the time of the entering sunlight using the keps of 24/9, not the keps of 18/9, via satpc32. 
73 de andy g0sfj

From: Greg D. <ko6th_greg at hotmail.com>
To: andy thomas <andythomasmail at yahoo.co.uk>; amsat <amsat-bb at amsat.org>
Sent: Saturday, 24 September 2011, 17:46
Subject: RE: [amsat-bb] Re: ARISSat daylightpower recovery time

Based on posted observations, I have come to the conclusion that the satellite's MET comes up at either 0 or 1 when the satellite turns on, after the 10-or-so minute delay after entering sunlight.  Depending on what mode it thinks it should be in, I suppose it's possible that it might in fact be in one of those power saving quiet periods at that time, and only be heard a few minutes later.  Entering sunlight is not a knife-edged event in orbit; there's a short ramp in power, so (playing arm-chair engineer here) I expect it would be in low or emergency power mode for a short while.

Greg  KO6TH

> Date: Sat, 24 Sep 2011 11:49:36 +0100
> From: andythomasmail at yahoo.co.uk
> To: amsat-bb at amsat.org
> Subject: [amsat-bb] Re: ARISSat daylightpower recovery time
> Did not catch the second voice digit! "MET is One shhhhhh"  But satellite is switched on.
> On 18 september the voice announced MET (19 and 21) equalled the time in sunlight, as I have calculated back using today's keps, within 1 minute. Allowing for keps 1 week old I think the MET is in fact announcing the time the satellite "wakes up" as she enters sunlight, but there are no fm transmissions at that time. The latency is up to 10 -19 minutes (if I had the second digit I could be more precise,hi!!)
> From: andy thomas <andythomasmail at yahoo.co.uk>
> To: amsat <amsat-bb at amsat.org>
> Sent: Saturday, 24 September 2011, 11:24
> Subject: Re:ARISSat daylightpower recovery time
> I agree with this observation here at IO92NL. 
> Arissat-1 does not switch on immediately when in sunlight, I have missed several passes this morning and in the last few days. 
> I am just waiting for what the MET is announced (voice tlm) as at 1032 utc AOS (coming up) and will backtrack to how long she has been in sunlight. The difference ought to tell us the latency.
> 73 de andy G0SFJ
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