I would like to ask the SatNOGS community for some additional observations of ASRTU-1 (AO-123) over the next one or two days.
ASRTU-1 has been suffering from a long-term power shortage because its deployable solar panels failed to deploy after launch. Recently, the Harbin Institute of Technology team has also been busy working on a new amateur satellite, while their ground station is currently unavailable due to renovation work at the university. As a result, timely attitude adjustments have become difficult, which has further affected the satellite’s power situation.
Over the past few days, command uplinks and telemetry operations have mainly been carried out by me together with the Foshan ground station.
Two days ago, we uploaded new commands intended to adjust the satellite’s attitude. However, it appears that the satellite may not have successfully completed the expected detumbling process. After the angular rate increased, it automatically entered rate damping mode and subsequently transitioned into three-axis control mode. As a result, the attitude did not change as expected from our commands.
We have just discovered that the battery voltage is lower than expected and have urgently uploaded another set of commands in an attempt to improve the situation.
Therefore, I would greatly appreciate it if SatNOGS station operators could schedule some additional observations of ASRTU-1 during the next 24–48 hours. Additional telemetry and observations from different parts of the world would be very helpful for us in assessing its current power and attitude-control status.
Thank you very much for your help and continued support of ASRTU-1!
ASRTU-1 uses a 3S3P Li-ion battery pack. In the telemetry, “Bus Voltage” refers to the battery pack voltage itself, so this is the main value to look at when evaluating the battery condition. A bus voltage below about 10.5 V indicates that the battery level is relatively low.
The charger voltage is also related to the bus/battery voltage to some extent, so it can be used as an additional reference.
The 12 V and other regulated voltage readings should not be used to judge the battery state, as those are regulated outputs after the DC-DC converters.
First of all, thank you very much for your continued support and observations of ASRTU-1!
Regarding the QSL card, you may need to contact lilacsat@hit.edu.cn. The team has been quite busy recently, so the response may not always be very timely. I haven’t received my QSL card yet either.
I’m extremely happy to hear that ASRTU-1 is in good health !! Unfortunately, I haven’t been able to track the satellite these past few days because of my work.
I have a question about the FM repeater: It’s well known that the satellite sends telemetry shortly after a voice signal is relayed and no other signal is detected by the satellite.
Is it known why this sometimes doesn’t happen ?? I’ve noticed countless times that telemetry isn’t transmitted a few seconds after an FM signal is relayed (this usually happens or used to happen after a few days of activity on the FM repeater)
I’m almost certain that the ASRTU-1 underwent an improvement in its telemetry logic, and after that update if I’m not mistaken this problem disappeared (which obviously leads me to believe it was an issue with that telemetry logic). Is that correct?
BTW, I never posted the photos of BY2HIT and BG2FWT QSL card and my ASRTU-1 diploma (which, unfortunately, was crumpled by the mail carrier ) :
There were indeed several issues with the original telemetry and FM repeater logic. For example, the interval was too short and could sometimes interrupt communication between operators. There was also an issue with the FM modulation index, which resulted in poor audio quality through the repeater, as well as the telemetry disappearing after the system had been running for a long time.
BY2HIT later fixed these issues and uploaded the updated software to the satellite in orbit. So far, there don’t seem to be any major problems with the current version.
5W + V/U directional antenna is more than enough for basically any LEO FM satellite. Make the most of it, because the AO-123 repeater is one of the best we have
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