Re: Tracking LightSail..

From: Greg Roberts via Seesat-l <>
Date: Fri, 29 May 2015 06:50:36 +0200
Morning Derek

Re LIGHTSAIL - as readers here should know Ted Molczan issued pre-launch 
elements for LIGHTSAIL.
I used them to receive radio transmissions at 1904UT on the 20th May 
shortly after it was switched
on.  Then new elements were released ( by presumably the LIGHTSAIL 
owners)  which showed that
  Teds elements were about 1 or 2 minutes out and I used these elements 
to track another pass by
radio ( the satellite was in earths shadow at the time - I have not 
checked what the status is now
since it is of no real interest to me), so PLANETARY.ORG appear to have 
issued at least one set of
elements and probably more since the satellite did transmit for a few 
days before the software
glitch crashed the on-board computer thus rendering the satellite silent 
and the satellite was
tracked by several other people by radio before the silence .

SPACETRACK have, and are, releasing elements for all ten ULTRASATS. I 
have seen them - I did not
get them from SPACETRACK and I am not sure what the "secrecy" status is 
but assume that these
elements for the ten ULTRASAT are available to the ULTRASAT owners. The 
problem is that neither
SPACETRACK nor the ULTRASAT owners really know which object is which 
ULTRASAT and until they
have dispersed in orbit - they were released more or less in a cluster 
so all closely spaced together -
and the ULTRASATS start transmitting it is not that easy, if possible,  
to identify which is which.

Optical tracking (at least by amateurs ) will not be able to resolve 
this issue as the objects are small
and thus pretty faint - I could probably track them if I use the setup I 
use for GEOSATS - but will not be
able to do no better than SPACETRACK - i.e track an object but not know 
which actual ULTRASAT
is which,   so until the ULTRASATS start transmitting - not all 
frequencies used are in the public
domain - the identities cannot be determined.   No doubt once this is 
done the elements will appear
in the normal data released by SPACETRACK.  As far as I know only one of 
currently transmitting. I have been too busy with the OTV-4 mission to 
worry about these satellites
and would not have normally bothered with them but I am thinking about 
doing some monitoring
just to hear them for fun . I doubt that I will be trying any optical 
though - except possibly LIGHTSAIL
IF the spacecraft computer can be re-booted and the mission completed.

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Received on Thu May 28 2015 - 23:51:32 UTC

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