[neo_followup] {MPML} C1979M1 earth-orbiting object (maybe artificial) decent chance of Earth impact on September 1. FOLLOWUP NEEDED ASAP!!!!!!

[Bill Gray]

Hi folks,

    Okay,  I've had a little more opportunity to dig into this,
plus some additional data from David Briggs at (J69).  Here's
everything I've got :

https://projectpluto.com/temp/64054a.htm

    This is just using some data from earlier in August,  plus
the recent C1979M1 observations.  The ephemerides show the
currently predicted ground path... which involves a close
perigee in about fourteen hours (at 15:06 UTC on the 27th),
slowing it down a bit,  then a re-entry around 21:00,
probably around French Polynesia.

    Quite a bit depends on how much the spacecraft slows down
after the upcoming perigee,  and there's considerable guessing
involved in that.  The above orbit is based on assuming the AMR
for solar radiation pressure is the same as that for atmospheric
drag,  which is pretty stupid,  but probably close enough for
the current situation.  More data tomorrow,  after perigee,
ought to show just how much the object got slowed down.

    To compute ephemerides for this object,  you'll need the
"current" Find_Orb (for Windows users,  the version described at

https://www.projectpluto.com/find_con.htm

    The older,  GUI version and the on-line Find_Orb don't
support the trickery I'm about to describe.)

    Cut-and-paste this e-mail into Find_Orb,  including the data
shown below.  Easiest way is to select all,  copy,  run Find_Orb,
and click on "Copy astrometry from clipboard".

    You'll get a pretty good orbit,  except one that doesn't
know anything about atmospheric drag.  We don't have enough data
here to determine an AMR,  so you have to help Find_Orb along.

    Hit the '*' key to turn on solar radiation pressure.  (If
the Find_Orb window is wide enough,  you may have an 'SRP' option
at the top and can click on that instead.)  Now right-click on
the orbital elements,  then on "Constraints=(none)".  Enter
'A=.03'.  Do a full step or two (hitting the 'f' key will do that).

    In truth,  that value may be off by quite a bit.  But even if
it is,  I think it'll be close enough to put you within a few
arcminutes of the object (I tried a range of AMRs,  and that's
about the spread I get.)

    You should now be able to generate customized ephemerides for
your location.

    Once we have some post-perigee data,  we should be able to fit
it without constraining the AMR,  and will have a _much_ better
idea as to the re-entry path.

-- Bill

COM = 1964-054A
      C1979M1* C2020 08 26.22870 21 19 52.55 +16 27 32.5    ~8Q6M 15.7 GVNEOCP703
      C1979M1  C2020 08 26.24365 21 19 41.29 +16 42 30.8    ~8Q6M 15.7 GVNEOCP703
      C1979M1  C2020 08 26.29283 21 19 02.64 +17 28 19.3    ~8Q7M 15.5 GVNEOCPI52
      C1979M1  C2020 08 26.29299 21 19 02.53 +17 28 27.7    ~8Q7M 15.7 GVNEOCPI52
      C1979M1  C2020 08 26.29314 21 19 02.42 +17 28 35.8    ~8Q7M 15.6 GVNEOCPI52
      C1979M1  C2020 08 26.29329 21 19 02.31 +17 28 44.0    ~8Q7M 15.4 GVNEOCPI52
      C1979M1  C2020 08 26.32367821 20 57.83 +17 12 40.7    ~8Q8M 15.6 GVNEOCPU55
      C1979M1  C2020 08 26.32554421 20 57.92 +17 14 19.6    ~8Q8M 15.5 GVNEOCPU55
      C1979M1  C2020 08 26.32766221 20 58.01 +17 16 11.3    ~8Q8M 15.6 GVNEOCPU55
      C1979M1  C2020 08 26.33511 21 18 36.03 +18 03 41.5    ~8Q8M 15.4 GVNEOCPI52
      C1979M1  C2020 08 26.33526 21 18 35.95 +18 03 48.8    ~8Q8M 15.3 GVNEOCPI52
      C1979M1  C2020 08 26.33541 21 18 35.88 +18 03 56.2    ~8Q8M 15.6 GVNEOCPI52
      C1979M1  C2020 08 26.33557 21 18 35.81 +18 04 03.5    ~8Q8M 15.8 GVNEOCPI52
      C1979M1  C2020 08 26.39013 21 18 28.43 +18 44 27.3    ~8Q9b 15.7 GVNEOCPI52
      C1979M1  C2020 08 26.39028 21 18 28.45 +18 44 34.2    ~8Q9b 15.7 GVNEOCPI52
      C1979M1  C2020 08 26.39044 21 18 28.50 +18 44 40.2    ~8Q9b 15.5 GVNEOCPI52
      C1979M1  C2020 08 26.39059 21 18 28.53 +18 44 46.6    ~8Q9b 15.8 GVNEOCPI52
      C1979M1  C2020 08 26.40323 21 19 26.00 +18 33 47.0    ~8QA7 15.7  rNEOCP718
      C1979M1  C2020 08 26.40415 21 19 26.56 +18 34 25.3    ~8QA7 15.8  rNEOCP718
      C1979M1  C2020 08 26.40506 21 19 27.14 +18 35 03.0    ~8QA7 15.7  rNEOCP718
      C1979M1  C2020 08 26.40597 21 19 27.76 +18 35 41.9    ~8QA7 15.8  rNEOCP718
      C1979M1  C2020 08 26.40688 21 19 28.34 +18 36 19.4    ~8QA7 15.8  rNEOCP718
      C1979M1  C2020 08 26.41689 21 18 40.80 +19 02 24.1    ~8QA7 16.2 GVNEOCPI52
      C1979M1  C2020 08 26.41700 21 18 40.87 +19 02 28.7    ~8QA7 15.5 GVNEOCPI52
      C1979M1  C2020 08 26.41711 21 18 40.95 +19 02 33.1    ~8QA7 15.9 GVNEOCPI52
      C1979M1  C2020 08 26.41739 21 18 41.13 +19 02 43.8    ~8QA7 15.4 GVNEOCPI52

COD J69
CON David Briggs [davidbriggs124 at googlemail.com]
OBS D. Briggs
MEA D. Briggs
TEL 0.41-m f/4.5 Newtonian reflector + CCD
ACK MPCReport file updated 2020.08.26 22:32:56
AC2 davidbriggs124 at googlemail.com
NET Gaia DR2
1964-054A    KC2020 08 26.92697721 55 22.19 +26 08 09.1          15.8 G      J69
1964-054A    KC2020 08 26.92801421 55 23.25 +26 09 18.4          15.9 G      J69
1964-054A    KC2020 08 26.92905221 55 24.32 +26 10 27.8          15.8 G      J69
1964-054A    KC2020 08 26.93009121 55 25.41 +26 11 37.0          16.0 G      J69
1964-054A    KC2020 08 26.93112721 55 26.45 +26 12 46.2          16.0 G      J69
1964-054A    KC2020 08 26.93216421 55 27.52 +26 13 55.2          15.9 G      J69
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