Steffan Watkins provided a wealth of AIS data from MarineTraffic about the journey of Yuan Wang 3 to the #Change5 re-entry skip point in the Arabian Sea. The data reveals that the ship did some interesting stop and goes prior to arriving on station to look at what? THREAD.
2020-12-10 UTC between 18:30 & 22:30, Mars was at the zenith when they stopped and set just before they got underway again. Perhaps providing support for TIANWEN-1 on the way to Mars?
2020-12-11 UTC between 14:20 & 22:05 more TIANWEN-1 watching at the zenith again it appears. The Mars bound probe has a big signal on X-band which is also used by #Change5.
2020-12-12 & 13th, 11:10 to 03:40 respectively, #Change5 TEI-2 (Lunar departure) would have been visible from the ship low in the east prior to it departing. A nearly full pass of TIANWEN-1 through the zenith would have been visible.
2020-12-13 between 14:20 & 15:20 a brief stop with Mars / TIANWEN-1 at the zenith. Starting to see a pattern here...
And then 2020-12-14 04:40 to 13:50 a prolonged stop to follow #Change5 after the first TCM-1 burn. With low lunar declination Yuan Wang 3 could be filling a coverage gap now in the Chinese DSN between China and Argentina.
Yuan Wang 3 has begun to loiter at the expected skip perigee spot in the Arabian Sea. I think the prolonged pauses in the trip here to Mars/TIANWEN-1 gaze may have been training sessions with a real radio signal at the zenith in the sky....
#Change5's re-entry will be largely at the zenith over the ship so testing systems and procedures may have been performed using the very handily located signal some 100 million km away from TIANWEN-1. H/T to @MarineTraffic and @steffanwatkins for the data and support.

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More from @coastal8049

15 Dec
Here's a plot of an estimated ground track for the #Change5 re-entry.
This THREAD will discuss:
- Evidence supporting this ground track,
- Alternatives that have been excluded,
- 'Skip' re-entry profile visibility characteristics,
- State vector confirmation of timings/position.
Two possible re-entry ground tracks have been explored. The one presented is favoured because the tracking ship Yuan Wang 3 is now presently at the 'skip re-entry perigee'. Using AIS data dug up by @steffanwatkins the ship has been loitering in the area for a day or so now.
@Cosmic_Penguin noted the following graphics posted during pre-launch coverage of training efforts which showed the location of Yuan Wang 3 and the major re-entry event locations. Despite some oddness in the presented data the plan looks solid.
Read 14 tweets
14 Dec
I consulted with Astrogator Mike and we are getting closer to a ground track estimate for #Change5 during re-entry. The s/c will skip off the atmosphere over Yemen. The timing of this is directly related to TCM corrections and the accuracy of our model so should improve. THREAD
#Change5 like the Apollo capsules will use the atmosphere to steer itself. Thus creating a lot of complexity and uncertainty in modelling the actual ground track to aid observers. We are looking at a few ways to spit ball a ground track for those living in the general area.
As it will be night time over this part of the world it should be a spectacular show for those lucky enough to see it.
Read 4 tweets
16 Sep
I've reached the conclusion that LES-5 has a 'BAD ATTITUDE' or maybe its just being obstreperous! If you look carefully at this plot you'll see there are two nulls and peaks in the signal in a day. The gaps at the bottom/top eclipses, mid is me tracking something else. THREAD Image
LES-5's antenna system has a beam-width around 35 degrees. If the satellite can't keep it's spin axis parallel Earth's axis than if it tilts more than 17.5 degrees up or down signal levels will be noticeably different twice a day. Image
The tilt in LES-5's spin axis is called it's attitude. Controlled by a novel arrangement of electro-magnetics and an optical sensor system we have been studying in the telemetry. LES-5's attitude control system seems to have either completely failed or is only partially working. Image
Read 4 tweets
15 Sep
The mysterious Chinese payload [46395, 2020-063G] deployed by their suspected spaceplane just passed over me. I tracked with the dish and was rewarded with a huge signal. Evidence in data it may be tumbling. IQ recording made and heading your way @ea4gpz @R4UAB ImageImage
Here's the Doppler analysis of the full pass IQ data. Very unusual modulation for a Chinese satellite. ImageImageImage
With all this data bandwidth I wonder if this is the 21st century version of 'The East is Red' in digital format?
Read 6 tweets
14 Sep
Following the penumbral eclipse of LES-5 on 2020-09-05 I've been able to identify all of the data words that are sensitive to solar illumination. Interesting patterns noted may help gain some insight into the present operation of the attitude control system. [THREAD]
36 of 128 data words responded to the penumbral eclipse(PE). A PE is the only way to know which data words are sensitive to solar illumination as LES-5 switches off during umbral eclipses. PEs only occur twice during each equinox and it may not be visible to me. So I got lucky. Image
Now I was able to see what appeared as relatively undynamic data words reveal they were sensitive to solar illumination. Frame1 word23 and frame3 word23 jumped out as they appeared to respond to something relating to the period of the LES-5. ImageImage
Read 9 tweets
5 Sep
The Fall equinox is closing in fast and LES-5 encountered its first brush with the penumbra of the Earth's shadow last night. It didn't switch the spacecraft off but you could clearly see the effects of the eclipse in the spacecraft's telemetry. [THREAD] ImageImageImageImage
The data words shown in the proceeding tweet are suspected as being from solar power converters on LES-5. I discussed these at length early this year in this blog post.…
Zooming in on the 4 data words of interest reveals an interesting correlation between their values and the timing of the eclipse. Please see the referenced blog post above to understand the aliased nature of the data plots below. You can clearly see a pronounced dip in the data. ImageImageImageImage
Read 5 tweets

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