Looking for TLEs from 1979

From: Bill Gray via Seesat-l <seesat-l_at_satobs.org>
Date: Mon, 5 Sep 2016 19:30:30 -0400
Hello all,

     As some of you know,  I'm involved with computing orbits for
higher-flying (multi-day) artificial satellites.  The higher
artsats move at about the same speed as the closer asteroids,
which tends to annoy the asteroid surveys.  They will find an
artsat,  briefly think they've found a really interesting rock
about to come near the earth or hit it,  only to find out it's
just a piece of junk.  They find this disappointing,  but there's
enough leftover junk in high orbits that it happens every now
and then.

     I've computed orbits for these as they are found,  both so
that they can be easily identified the next time the surveys
stumble across them,  and because there's some hope of one of
them hitting the earth or moon.  (So far,  we've had one hit
the earth -- WT1190F,  last November,  near Sri Lanka -- and a
few close passes by both earth and moon.)  See


     for some examples.

     Anyway.  The SONEAR survey in Brazil picked up an object last
night,  to which they have given the designation S510923.  It's
in a nearly circular orbit around us,  with a period of about
five days.  (Still some fuzziness in this,  which further
observations will,  I hope,  cure.)

     It's likely that this is related to the 1976 SOLRAD 11 mission.
This put two probes (SOLRAD 11A,  a.k.a. 1976-023C,  and SOLRAD
11B,  a.k.a. 1976-023D) and an apogee kick motor (1976-023H)
into this sort of orbit.  The folks at the Catalina Sky Survey in
Arizona have found SOLRAD 11A,  so it's nicely accounted for and
we know S510923 isn't it :


     SOLRAD 11B kept going until 1979.  We do have a TLE for it
from 1977,  and the match to S510923 is quite encouraging.  But
if anyone has historical data from 1979 and can provide a TLE
for SOLRAD 11B with a more recent epoch,  it might really help
figure out what's going on here.

     Observations and an orbit for S510923,  in the Minor Planet
Center's formats,  are at


Thanks!              -- Bill
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Received on Mon Sep 05 2016 - 18:31:08 UTC

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