AO-73 : Funcube-1

Spin Period
09 Aug 2019 = 41.1 seconds (from averaged panel temperatures)
10 Aug 2019 = 37.8 seconds (from averaged panel temperatures)
11 Aug 2019 = 35.1 seconds (from averaged panel temperatures)
12 Aug 2019 = 32.6 seconds (from averaged panel temperatures)
13 Aug 2019 = 29.8 seconds (from averaged panel temperatures)
14 Aug 2019 = 27.8 seconds (from averaged panel temperatures)
15 Aug 2019 = 26.8 seconds (from averaged panel temperatures)

73 de Colin VK5HI.

AO-73 : Funcube 1

Spin Period
02 Aug 2019 = 68.6 seconds (from averaged panel temperatures)
03 Aug 2019 = 65.0 seconds (from averaged panel temperatures)
04 Aug 2019 = 60.2 seconds (from averaged panel temperatures)
05 Aug 2019 = 56.3 seconds (from averaged panel temperatures)
06 Aug 2019 = 52.1 seconds (from averaged panel temperatures)
07 Aug 2019 = 48.1 seconds (from averaged panel temperatures)
08 Aug 2019 = 44.8 seconds (from averaged panel temperatures)

Both my solar prediction programs, Stacey W4SM’s SolarC.exe and Mike DK3WN’s Illum.exe both showed AO-73 entered full sun early on the UTC morning of the 9th August.
Over the last week AO-73 has developed a small level of Nutation associated with increased rotational speed.

73 de Colin VK5HI.

AO-73 : Funcube-1

Spin Period
26 July 2019 = 112.9 seconds (from averaged panel temperatures)
27 July 2019 = 104.3 seconds (from averaged panel temperatures)
28 July 2019 = 96.8 seconds (from averaged panel temperatures)
29 July 2019 = 90.3 seconds (from averaged panel temperatures)
30 July 2019 = 84.8 seconds (from averaged panel temperatures)
31 July 2019 = 77.5 seconds (from averaged panel temperatures)
01 Aug 2019 = 74.6 seconds (from averaged panel temperatures)

In approximately one week’s time AO-73 will be in full sun once again.
Over the last two weeks as the eclipse period has started to shorten we
have again noted AO-73’s Propeller Effect on the spin period.

73 de Colin VK5HI.

AO-73 : Funcube-1

Spin Period
12 July 2019 = 136.8 seconds (from averaged panel temperatures)
13 July 2019 = 125.0 seconds (from averaged panel temperatures)
14 July 2019 = 118.3 seconds (from averaged panel temperatures)
15 July 2019 = 120.9 seconds (from averaged panel temperatures)
16 July 2019 = 135.4 seconds (from averaged panel temperatures)
17 July 2019 = 153.1 seconds (from averaged panel temperatures)
18 July 2019 = 133.8 seconds (from averaged panel temperatures)

73 de Colin VK5HI.

AO-73 : Funcube – 1

Spin Period
05 July 2019 = 194.7 seconds (from averaged panel temperatures)
06 July 2019 = 167.5 seconds (from averaged panel temperatures)
07 July 2019 = 164.7 seconds (from averaged panel temperatures)
08 July 2019 = 155.5 seconds (from averaged panel temperatures)
09 July 2019 = 144.4 seconds (from averaged panel temperatures)
10 July 2019 = 136.3 seconds (from averaged panel temperatures)
11 July 2019 = 127.3 seconds (from averaged panel temperatures)

73 de Colin VK5HI.

AO-73 : Funcube-1

Spin Period
28 Jun 2019 = 178.8 seconds (from averaged panel temperatures)
29 Jun 2019 = 155.3 seconds (from averaged panel temperatures)
30 Jun 2019 = 144.7 seconds (from averaged panel temperatures)
01 July 2019 = 143.5 seconds (from averaged panel temperatures)
02 July 2019 = 150.4 seconds (from averaged panel temperatures)
03 July 2019 = 138.7 seconds (from averaged panel temperatures)
04 July 2019 = 189.7 seconds (from averaged panel temperatures)

73 de Colin VK5HI.

AO-73 : Funcube-1

Spin Period
21 Jun 2019 = 154.7 seconds (from averaged panel temperatures)
22 Jun 2019 = 139.7 seconds (from averaged panel temperatures)
23 Jun 2019 = 132.0 seconds (from averaged panel temperatures)
24 Jun 2019 = 139.1 seconds (from averaged panel temperatures)
25 Jun 2019 = 150.0 seconds (from averaged panel temperatures)
26 Jun 2019 = 143.0 seconds (from averaged panel temperatures)
27 Jun 2019 = 144.7 seconds (from averaged panel temperatures)

73 de Colin VK5HI.

AO-73 : Funcube-1

Spin Period
07 Jun 2019 = 132.3 seconds (from averaged panel temperatures)
08 Jun 2019 = 144.3 seconds (from averaged panel temperatures)
09 Jun 2019 = 162.6 seconds (from averaged panel temperatures)
10 Jun 2019 = 151.6 seconds (from averaged panel temperatures)
11 Jun 2019 = 134.7 seconds (from averaged panel temperatures)
12 Jun 2019 = 143.6 seconds (from averaged panel temperatures)
13 Jun 2019 = 157.1 seconds (from averaged panel temperatures)

During the week Dave G4DPZ downloaded the last 3 weeks of WOD’s for me to analyse.
Having analysed each orbit for the 22nd, 23rd, 24th and 25th May and calculated the spin
period using the +X Panel Temperature I now “appreciate” what is happening during each
orbit of AO-73. The reasoning as to “why” it is happening requires further research.

73 de Colin VK5HI.

AO-73 : Funcube-1

Spin Period
24 May 2019 = 193.0 seconds (from averaged panel temperatures)
25 May 2019 = 160.7 seconds (from averaged panel temperatures)
26 May 2019 = 148.5 seconds (from averaged panel temperatures)
27 May 2019 = 137.3 seconds (from averaged panel temperatures)
28 May 2019 = 182.4 seconds (from averaged panel temperatures)
29 May 2019 = 162.6 seconds (from averaged panel temperatures)
30 May 2019 = 133.5 seconds (from averaged panel temperatures)

As AO-73 has gradually encountered greater eclipse periods it has developed a cyclic spin period.
Strongly suspect propeller effect and relative point of observation (time and location).
From previous analysis of WOD’s we know spin can vary throughout a 24 hour period.
Will investigate further.

73 de Colin VK5HI.

AO-73 : Funcube-1

Spin Period

17 May 2019 = 176.8seconds (from averaged panel temperatures)
18 May 2019 = 168.0 seconds (from averaged panel temperatures)
19 May 2019 = 148.5 seconds (from averaged panel temperatures)
20 May 2019 = 149.2 seconds (from averaged panel temperatures)
21 May 2019 = 147.0 seconds (from averaged panel temperatures)
22 May 2019 = 135.2 seconds (from averaged panel temperatures)
23 May 2019 = 190.5 seconds (from averaged panel temperatures)

Have no explanation for the sudden change in spin period on 23rd May.
Any commands issued over the last couple of days, abnormal high currents, whatever ??

As of today (23rd May) we now experiencing 18.0 minute eclipse periods per orbit.
Come early June we will stabilise at 20 minutes per orbit until early July when the
eclipse periods again shorten such that we again enter full sun on the 9th August.

73 de Colin VK5HI.