March 2021 - 18SPCS reported that YUNHAI 1-02 [44547, 2019-063A] had broken up. Since the breakup report, amateurs have monitored radio emissions on 1704MHz. As the spacecraft straddles the terminator it was lost in the glare of daylight until now...
@18SPCS reported that YUNHAI 1-02 broke up and amateurs noticed it continued to emit. The following thread should catch you up on some of these facts.
@planet4589 later noted an anomolly in the @SpaceTrackOrg catalogue with a report indicating 48078, 1996-051Q: "Collided with satellite". See this great thread to learn more about his analysis and the tie to YUNHAI 1-02.
In preparation for visual observations, reviewed MMT data for similar phase angle observations that had occurred in the previous couple years and one that occurred a year ago today 2020-10-08. Similar phase angle and note the obvious periodic light curve.… ImageImageImage
These three images taken approximately at 2021-10-09T03:26 UTC, with a 10s exposure, reveal a 'steady' light curve for YUNHAI 1-02 nothing close to the historically observed 3.33s period with an amplitude of ~2 magnitudes. ImageImageImage
Here's the planning plot for the encounter to give you some perspective. STARLINK-1495 [45761, 2020-038AH] is also in two of the frames travelling perpendicular to YUNHAI 1-02. Image
What does this all mean?
1 - YUNHAI 1-02 appears to be on a reduced mission.
2 - It's scanning radiometer appears to have been damaged or deactivated as they usually cause rapid periodic flashes from a satellite which explains the old period of 3.33s.… Image

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More from @coastal8049

16 Jan
Well well well, the mystery of what the signal on ~992.4MHz/~1000.44MHz and FM audio on ~998.94MHz from the Meridian satellites is resolved. It's SECAM TV channels from Turkmenistan. SECAM channel spacing is 8MHz and video carrier to audio carrier is 6.5MHz which matches.
I mused a few weeks about about the curious nature of the 15.625MHz sub-carriers around the primary.
Here you can find some info on the SECAM channel frequencies. Look up France, Eastern Europe, Former Soviet Union, French overseas territories and former French colonies in Africa, North Korea, Vietnam...…
Read 7 tweets
15 Dec 20
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.
Read 8 tweets
15 Dec 20
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 20
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 20
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 20
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

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