Meridian 8: failed or just different?

From: Scott Tilley via Seesat-l <seesat-l_at_satobs.org>
Date: Tue, 7 Jan 2020 19:34:37 -0800
Hi All

Meridian 8 appeared to be launched (July 30, 2019) almost immediately 
after Meridian 3 stopped transmitting last summer. Here's a TASS report 
after the Meridian 8 launch saying all is good with the spacecraft.

https://tass.com/science/1070982

This report doesn't seem to match months of radio observations and now a 
new Meridian-M is scheduled for launch this month.

Meridian 8 entered Meridian 3's orbital plane and the orbit became 
synchronous in mid August. However, Meridian 8 didn't emit any signals 
on X-band or either of the UHF bands used by Meridian satellites.  I 
lack C-band capability so don't know what is going on there.

The rest of the constellation emits transponder and TT&C signals when 
the spacecraft is near apogee. The X-band tracking beacons can be seen 
here:

https://twitter.com/coastal8049/status/1161140563611045889/photo/1

The image above was plotted last summer.  I just revised the 
constellations status after noting a TASS report that the launch of 
Meridian-M is planned for this January.

https://tass.com/defense/1104437

Here's a plot showing the X-band emissions from the tracking beacons for 
Meridian 2, 4, 6 and 7.  No emissions are noted in the "Meridian 3 
gap".  Meridian 2's booster malfunctioned and placed it into a 
non-standard orbit.  It has been in operation on X-band since I started 
monitoring there for at least 2 years, but it is not in a synchronous 
orbit and not part of the constellation.

https://twitter.com/coastal8049/status/1214738381134938112

I find this unusual as from my understanding the new Meridian-M version 
of the satellite is simply a slightly improved variant of the Meridian 
satellite and four Meridian-M's were commissioned to replace aging 
Meridian spacecraft rather then develop new ones. So why would it have 
different operational behaviour then the rest of the constellation? That 
makes no sense as it implies that the ground segment would also need to 
change.

I suspect the up coming launch may be a replacement for Meridian 8.  If 
that is the case this new launch would occur into the Meridian 3's 
plane. The next oldest satellite in the constellation is Meridian 4 
which as of today is operational.  However, Russia did make a statement 
that it planned to launch two Meridian-M satellites in 2019, so maybe 
all is well with Meridian 8 because it's different and the new one is 
off to another plane...?

https://tass.com/defense/1061195

We will not know what's going on until the NOTAM's come out for this 
launch.

Has anyone ever bothered to look optically at the Meridian satellites?

Regards,

Scott Tilley

Further reading on Meridian - http://www.russianspaceweb.com/meridian.html

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Received on Tue Jan 07 2020 - 21:35:30 UTC

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