2018 Sep 7. Luch and Athena-FIDUS


OK, let's talk about this story about Luch-Olimp passing "too closely"
to the French-Italian military communications satellite ATHENA-FIDUS.

"AFP news agency
#UPDATE France said The Athena-Fidus satellite was approached "a bit too
closely" by Russia's Luch-Olymp craft, known for its advanced listening
capabilities http://u.afp.com/o2i6 "

Luch was launched in 2014 and has been moving in stages around the
geostationary belt, stopping for a while at 14 different locations so
far
<P>
<IMG WIDTH=400 SRC="luch1.jpg">
<P>


On Oct 20 2017, it passed the longitude where ATHENA-FIDUS is stationed (37.8E) - marked in red here

<P> <IMG WIDTH=400 SRC="luch2.jpg"> <P> 


It did this during a transition
from a stay at 32.7E (2017 Aug 17-Oct 16) to a stay at 38.2E (2017 Oct 24 to 2018 Jan 17)

<P> <IMG WIDTH=400 SRC="luch3.jpg"> <P> 

The previous image might lead you to think it was parked next to
ATHENA-FIDUS, but let's mark the other operational geosats in that
longitude range. The Oct-Jan parking slot was actually closer to
PAKSAT-1R.

<P> <IMG WIDTH=400 SRC="luch4.jpg"> <P> 

The geostationary belt is very narrow - you have to be at exactly the
right distance from the Earth (average dist within 1 km of the critical
value) and right on the equator (typically less than 100 km north/south,
and usually more like 10 km for sats that aren't too old)

This is a plot of Luch passing ATHENA-FIDUS in the equatorial plane.
Luch made a braking maneuver around this time as it approached its next
slot; the blue and cyan curves show the pre and post maneuver curves
since I'm not sure exactly when the burn was

<P> <IMG WIDTH=400 SRC="luch5b.jpg"> <P> 

My calculations using the public TLEs and the SGP4 orbit model show a
closest approach of about 85 km, which is pretty typical given you're
drifting in GEO and GEO is very narrow. Very possible my code is wrong -
I'd welcome others to do an independent calc with STK or GMAT

A couple of days later Luch is settled into its new slot just to the
east of Paksat. I see no evidence in the data of a "too close" pass.

<P> <IMG WIDTH=400 SRC="luch6.jpg"> <P> 

Now, it's quite possible nevertheless that Luch is indeed intercepting
the communications of ATHENA-FIDUS and other satellites as it moves
around the belt. The US has satellites doing the same thing, so it's
what the lawyers call 'established state practice..'


See also @brianweeden's discussion of earlier Luch stuff at http://www.thespacereview.com/article/2839/2