Observation 7407297: Pleiades-Yearling (99206)

Regarding Observation 7407297

Hello! I’m one of the members of the Pleiades - Yearling team. Our satellite failed to deploy on SpaceX Transporter-6 in January 2023, as a result we have re-manifested on SpaceX Transporter-7 which is launching very soon.

I was thumbing through some of the SatNOGS observations on our preliminary TLE from January though and noticed that some of the observations show some sort of signal that repeats every 20s, and does not always curve with terrestrial noise. I’ve linked one of those observations here. Is there any way to try and flush out what this signal could be? I don’t believe there were any other satellites operation at 437.4 Mhz on this launch other than Yearling and our sister satellite Sapling. At least, there is no other IARU coordinated satellite we know of in this space.

Any thoughts on what we are seeing would be greatly appreciated!

If you have a look at the transmitters allocated in 437.4 range, it’s one of the busiest frequencies around. You can have a look at the individual ones and check some of the probable ones. By the width of it I’m guessing 1200baud fsk or something like that.

Hi @BroncoSpace and welcome to the community!

Thanks for the information. I’ve changed Pleiades - Yearling satellite to dead status and all the observations to bad status based on your post.

However I have some questions just to be sure:

  1. You are 100% that the satellite wasn’t deployed? Is there a chance that it was deployed but never heard?
  2. Do you know if the Sapling wasn’t deployed too?

Now about the signal you see, after getting all the satellites near to your satellite’s frequency from @SA2KNG link and running them through ikhnos for this observation I found that this signal is UPMSat-2.

Here is the ikhnos result for UPMSat-2 with the red line being 5KHz drifted as UPMSat-2 is at 437.405MHz:

You can see that the red line (the curve that UPMSat-2’s signal should follow if it was observed with the TLE used in this observation) follows pretty accurately the observed signal.

EDIT: I’ve also confirmed with a couple more observations that have observed the same signal.

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Hi @fredy thank you for the quick investigation! The brief hunt was fun while it lasted.

To answer your questions:

  1. We are as close to 100% sure that deployment never happened as we can be. Contact was lost with the Orbiter SN1 orbital transfer vehicle that we were hosted on very shortly after separation with the Falcon 9. In that time there as no confirmed deployment command and there was no system on-board to deploy our satellite without a verified signal from ground. The only way we could think there would be a miracle satellite would be if the deployer itself failed and allowed the door to open without any ground command, which should be extremely unlikely.

  2. Sapling Sempervirens was co-manifested on that flight and was in the same situation but in a different deployer pod. Within the first week after launch in January we thought there might have been some kind of miracle deployment, but we never observed any verified signals from a few weeks of tracking.

We are looking forward to the reflight of Pleiades Yearling (99184) and Sapling Giganteum (replacement for Sapling Sempervirens) today on SpaceX Transporter 7! Hopefully we’ll be getting strong signal from both!