Observation #308970 - EQUiSat and SiriusSat-1

This observation is marked bad but I can see at least 3 packets from EQUiSat between 150 - 250 seconds that are at the correct 40 sec. interval and 435.55 transmission doppler shift. The satellite battery is currently weak so the signal is rather low.

The same observation also includes packets from SiriusSat-1 which is transmitting on a similar frequency of 435.57 and shows up as a drifting + doppler shift in the waterfall.

These two satellites are in nearly identical orbits but with slightly different periods. During late Oct. and into Nov. the two will be above the horizon at that same time and moving along the same path. All captures recorded during this period will likely include both. I’ve seen at least a couple of others besides this one. We were a bit confused by the extra signals until we realized what was happening.

The satellites currently have a separation of about 900 km and the distance is decreasing each day. There is a very close approach on Nov. 5th. I estimate they will pass within about 5 or 6 km of each other.



I’m an adviser for Brown Space Engineering and the Radio Club K1AD


You’re right, I have changed vetting to good. Thanks for the notice!


Thank you. We’re likely to see more overlap of the two in the coming weeks.

I wrote up the orbital dynamics of the close approach on my blog. There’s some other posts under the spaceflight tag that might be of interest to the community.



Great and interesting analysis of the close approach in your blog post! Thank you!

cc @sputnix team about it.

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