Rotation Period

09 Apr 2021 = 22.0 seconds (from averaged panel temperatures)
10 Apr 2021 = 28.5 seconds (from averaged panel temperatures)
11 Apr 2021 = 26.9 seconds (from averaged panel temperatures)
12 Apr 2021 = 32.1 seconds (from averaged panel temperatures)
13 Apr 2021 = 36.7 seconds (from averaged panel temperatures)
14 Apr 2021 = 45.7 seconds (from averaged panel temperatures)
15 Apr 2021 = 51.5 seconds (from averaged panel temperatures)

AO-73 continues to rotate about the Z-Z axis in reverse of its normal spin direction, with the Z-Z axis maintaining an irregular movement about AO-73’s offset centre of mass. After reporting on April 10th that AO-73 had snapped from a complex unstable attitude to a less complex and an improved attitude, within 24 hours it had again resumed an unstable attitude again. The recommencement of eclipse periods on April 13th is again exhibiting differing frequency profiles for both the morning and evening passes.

73 de Colin VK5HI.

Rotation Period

02 Apr 2021 = 17.8 seconds (from averaged panel temperatures)
03 Apr 2021 = 17.1 seconds (from averaged panel temperatures)
04 Apr 2021 = 17.2 seconds (from averaged panel temperatures)
05 Apr 2021 = 17.8 seconds (from averaged panel temperatures)
06 Apr 2021 = 17.8 seconds (from averaged panel temperatures)
07 Apr 2021 = 19.0 seconds (from averaged panel temperatures)
08 Apr 2021 = 720 seconds (from real-time WOD panel temperatures)

This last week AO-73’s attitude was very unstable and the Dzhanibekov effect was possibly noted during a number of passes over VK. At some period on the 8th April AO-73 snapped from a complex unstable attitude to a less complex and an improved attitude.
On April 13th AO-73 will again start to experience eclipse periods.

73 de Colin VK5HI.

Rotation Period

26 Mar 2021 = 22.7 seconds (from averaged panel temperatures)
27 Mar 2021 = 21.8 seconds (from averaged panel temperatures)
28 Mar 2021 = 20.7 seconds (from averaged panel temperatures)
29 Mar 2021 = 20.2 seconds (from averaged panel temperatures)
30 Mar 2021 = 20.0 seconds (from averaged panel temperatures)
31 Mar 2021 = 19.7 seconds (from averaged panel temperatures)
01 Apr 2021 = 18.6 seconds (from averaged panel temperatures)

AO-73 continues to rotate about the Z-Z axis in reverse of its normal spin direction, with the Z-Z axis maintaining an irregular movement about AO-73’s offset centre of mass. On April 13th AO-73 will again start to experience eclipse periods.

73 de Colin VK5HI.

06 Mar 2021 = 34.0 seconds (from averaged panel temperatures)
07 Mar 2021 = 38.2 seconds (from averaged panel temperatures)
08 Mar 2021 = 40.0 seconds (from averaged panel temperatures)
09 Mar 2021 = 42.1 seconds (from averaged panel temperatures)
10 Mar 2021 = 43.6 seconds (from averaged panel temperatures)
11 Mar 2021 = 44.0 seconds (from averaged panel temperatures)
12 Mar 2021 = 32.8 seconds (from averaged panel temperatures)
13 Mar 2021 = 40.6 seconds (from averaged panel temperatures)
14 Mar 2021 = 38.5 seconds (from averaged panel temperatures)
15 Mar 2021 = 36.4 seconds (from averaged panel temperatures)
16 Mar 2021 = 34.5 seconds (from averaged panel temperatures)
17 Mar 2021 = 32.8 seconds (from averaged panel temperatures)
18 Mar 2021 = 31.0 seconds (from averaged panel temperatures)
19 Mar 2021 = 29.7 seconds (from averaged panel temperatures)
19 Mar 2021 = 29.7 seconds (from averaged panel temperatures)
20 Mar 2021 = 30.7 seconds (from averaged panel temperatures)
21 Mar 2021 = 26.7 seconds (from averaged panel temperatures)
22 Mar 2021 = 25.5 seconds (from averaged panel temperatures)
23 Mar 2021 = 24.4 seconds (from averaged panel temperatures)
24 Mar 2021 = 23.4 seconds (from averaged panel temperatures)
25 Mar 2021 = 23.5 seconds (from averaged panel temperatures)

AO-73 remains rotating about the Z-Z axis in reverse of its normal spin direction, with the Z-Z axis maintaining an irregular movement about AO-73’s offset centre of mass.

73 de Colin VK5HI.

Rotation Period

26 Feb 2021 = 18.1 seconds (from averaged panel temperatures)
27 Feb 2021 = 18.1 seconds (from averaged panel temperatures)
28 Feb 2021 = 17.0 seconds (from averaged panel temperatures)
01 Mar 2021 = 17.2 seconds (from averaged panel temperatures)
02 Mar 2021 = 19.7 seconds (from averaged panel temperatures)
03 Mar 2021 = 20.9 seconds (from averaged panel temperatures)
04 Mar 2021 = 24.6 seconds (from averaged panel temperatures)

73 de Colin VK5HI.

Rotation Period

19 Feb 2021 = 23.6 seconds (from averaged panel temperatures)
20 Feb 2021 = 23.6 seconds (from averaged panel temperatures)
21 Feb 2021 = 19.9 seconds (from averaged panel temperatures)
22 Feb 2021 = 19.9 seconds (from averaged panel temperatures)
23 Feb 2021 = 18.9 seconds (from averaged panel temperatures)
24 Feb 2021 = 18.3 seconds (from averaged panel temperatures)
25 Feb 2021 = 18.3 seconds (from averaged panel temperatures)

AO-73 is now “rotating” about the Z-Z axis in a very indeterminate manner.

73 de Colin VK5HI.

Rotation Period

12 Feb 2021 = 37.4 seconds (from averaged panel temperatures)
13 Feb 2021 = 35.9 seconds (from averaged panel temperatures)
14 Feb 2021 = 32.6 seconds (from averaged panel temperatures)
15 Feb 2021 = 30.3 seconds (from averaged panel temperatures)
16 Feb 2021 = 28.9 seconds (from averaged panel temperatures)
17 Feb 2021 = 27.1 seconds (from averaged panel temperatures)
18 Feb 2021 = 25.2 seconds (from averaged panel temperatures)

AO-73 continues to “wobble” about the Z-Z axis due to the uneven weight distribution about AO-73’s theoretical centre of mass. The influence of this “wobble” on the downlink signal over VK is very noticeable.

73 de Colin VK5HI.

Rotation Period

05 Feb 2021 = 63.2 seconds (from averaged panel temperatures)
06 Feb 2021 = 58.3 seconds (from averaged panel temperatures)
07 Feb 2021 = 56.5 seconds (from averaged panel temperatures)
08 Feb 2021 = 50.4 seconds (from averaged panel temperatures)
09 Feb 2021 = 46.9 seconds (from averaged panel temperatures)
10 Feb 2021 = 43.6 seconds (from averaged panel temperatures)
11 Feb 2021 = 40.9 seconds (from averaged panel temperatures)

With reducing Spin Period AO-73 over the last two weeks has commenced to “wobble” about the Z-Z axis due to the uneven weight distribution about AO-73’s theoretical centre of mass. The affect of this “wobble” on the downlink signal over VK is now very noticeable.

73 de Colin VK5HI.

Rotation Period

29 Jan 2021 = 111 seconds (from averaged panel temperatures)
30 Jan 2021 = 101 seconds (from averaged panel temperatures)
31 Jan 2021 = 90.3 seconds (from averaged panel temperatures)
01 Feb 2021 = 87.8 seconds (from averaged panel temperatures)
02 Feb 2021 = 79.1 seconds (from averaged panel temperatures)
03 Feb 2021 = 73.3 seconds (from averaged panel temperatures)
04 Feb 2021 = 67.5 seconds (from averaged panel temperatures)

73 de Colin VK5HI.

Rotation Period

08 Jan 2020 = 507 seconds (from averaged panel temperatures)
09 Jan 2020 = 455 seconds (from averaged panel temperatures)
10 Jan 2020 = 411 seconds (from averaged panel temperatures)
11 Jan 2020 = 381 seconds (from averaged panel temperatures)
12 Jan 2021 = 340 seconds (from averaged panel temperatures)
13 Jan 2021 = 324 seconds (from averaged panel temperatures)
14 Jan 2021 = 290 seconds (from averaged panel temperatures)
15 Jan 2021 = 259 seconds (from averaged panel temperatures)
16 Jan 2020 = 235 seconds (from averaged panel temperatures)
17 Jan 2020 = 217 seconds (from averaged panel temperatures)
18 Jan 2020 = 197 seconds (from averaged panel temperatures)
19 Jan 2020 = 181 seconds (from averaged panel temperatures)
20 Jan 2021 = 166 seconds (from averaged panel temperatures)
21 Jan 2021 = 153 seconds (from averaged panel temperatures)
22 Jan 2021 = 175 seconds (from averaged panel temperatures)
22 Jan 2021 = 175 seconds (from averaged panel temperatures)
23 Jan 2021 = 145 seconds (from averaged panel temperatures)
24 Jan 2021 = 136 seconds (from averaged panel temperatures)
25 Jan 2021 = 161 seconds (from averaged panel temperatures)
26 Jan 2021 = 175 seconds (from averaged panel temperatures)
27 Jan 2021 = 125 seconds (from averaged panel temperatures)
28 Jan 2021 = 115 seconds (from averaged panel temperatures)

73 de Colin VK5HI.