Re: Lewis decay

Jeremy Ollerenshaw (jolleren@earthlink.net)
Tue, 30 Sep 1997 20:29:22 -0700

J.C. Millot wrote:
>=20
> Hi Alan,
>=20
> (who answered me directly because he could not reach the See-Sat list f=
rom
> his office)
>=20
> and thanks for the fast answer.
>=20
> ----------
> > De : Alan Pickup <A.Pickup@roe.ac.uk>
> > A : papou@canl.nc
> > Cc : alan@wingar.demon.co.uk
> > Objet : Lewis decay
> > Date : mardi 30 septembre 1997 20:07
> >
> > Hello Papou,
> >
> > I'm delighted to get your report but I'm at work and unable from here
> > to post to SeeSat-L. A quick check implies that Lewis should, indeed,
> > have passed over or close to Noumea on that orbit at the time you say.
> > Please go ahead and gather as many reports from witnesses as you can
> > since it does appear that this is an important decay event. If you ca=
n
> > gather altitude/azimuth info for the track then that should help to
> > estimate its altitude and confirm the identity.
>=20
> I will try to gather further reports. The more serious one I got is fro=
m a
> guy driving on the small highway coming into Noumea City, in a suburb n=
amed
> Koutio.
>=20
> The exact position should be 22d13S and 166d27E
>=20
> His saw the object "high on the east and going down to the south". That
> seem to fit well with some predictions I made with "Ident" software fro=
m
> Alphonse Pouplier with the last elset you gave on the list.
>=20
> File: LEWIS.DAT
> Place: KOUTIO
> Lo.(DDDMM East):16627 La.(=F1DDMM):-2213
> Date (DDMMYY): 280997
> >From  5  min. before  till  5  min. after 1129 (HHMM  UT)
> Every 10 sec.
> Field of diameter  180 =F8 centered on:
> Azimuth:   180 =F8
> Altitude:  90 =F8
> ----------------------------------------------------------------------
>=20
> Lewis          1 24909U 97044A
> 28/ 9/1997  11h25m50s   Az.:  17   Alt.:   1
> 28/ 9/1997  11h26m 0s   Az.:  18   Alt.:   1
> 28/ 9/1997  11h26m10s   Az.:  18   Alt.:   2
> 28/ 9/1997  11h26m20s   Az.:  18   Alt.:   3
> 28/ 9/1997  11h26m30s   Az.:  19   Alt.:   4
> 28/ 9/1997  11h26m40s   Az.:  20   Alt.:   5
> 28/ 9/1997  11h26m50s   Az.:  21   Alt.:   6
> 28/ 9/1997  11h27m 0s   Az.:  22   Alt.:   8
> 28/ 9/1997  11h27m10s   Az.:  23   Alt.:  10
> 28/ 9/1997  11h27m20s   Az.:  25   Alt.:  12
> 28/ 9/1997  11h27m30s   Az.:  27   Alt.:  15
> 28/ 9/1997  11h27m40s   Az.:  31   Alt.:  19
> 28/ 9/1997  11h27m50s   Az.:  36   Alt.:  24
> 28/ 9/1997  11h28m 0s   Az.:  46   Alt.:  32
> 28/ 9/1997  11h28m10s   Az.:  65   Alt.:  41
> 28/ 9/1997  11h28m20s   Az.: 100   Alt.:  48
> 28/ 9/1997  11h28m30s   Az.: 136   Alt.:  42
> 28/ 9/1997  11h28m40s   Az.: 156   Alt.:  32
> 28/ 9/1997  11h28m50s   Az.: 167   Alt.:  24
> 28/ 9/1997  11h29m 0s   Az.: 172   Alt.:  19
> 28/ 9/1997  11h29m10s   Az.: 176   Alt.:  15
> 28/ 9/1997  11h29m20s   Az.: 178   Alt.:  12
> 28/ 9/1997  11h29m30s   Az.: 180   Alt.:  10
> 28/ 9/1997  11h29m40s   Az.: 182   Alt.:   8
> 28/ 9/1997  11h29m50s   Az.: 183   Alt.:   7
> 28/ 9/1997  11h30m 0s   Az.: 184   Alt.:   5
> 28/ 9/1997  11h30m10s   Az.: 184   Alt.:   4
> 28/ 9/1997  11h30m20s   Az.: 185   Alt.:   3
> 28/ 9/1997  11h30m30s   Az.: 185   Alt.:   2
> 28/ 9/1997  11h30m40s   Az.: 186   Alt.:   2
> 28/ 9/1997  11h30m50s   Az.: 186   Alt.:   1
> 28/ 9/1997  11h31m 0s   Az.: 186   Alt.:   0
>=20
> I will try to have more info from this guy and I will ask the local med=
ias
> for some more witnesses tomorrow morning as it is now 20:51 local time
>=20
> I will put all the info I gather on the See-Sat list as well as on the
> Alphonse french list.
>=20
> >
> > As a resident of "Old Caledonia", I would be very pleased if my SatEv=
o
> > calculation and speculation is vindicated by observers in New Caledon=
ia
> > :-)
>=20
> New Caledonia was named by Captain Cook when he discovered the main isl=
and
> on September 4th, 1774 because what he saw at the first glance reminded=
 him
> of his land of birth, Caledonia. Of course when he got closer the day
> after, he saw that there were white sand beaches, coconut trees and
> melanesian people living on the island. -:)
>=20
> Jean-Christophe 'Papou' Millot - Computer and Network Consultant
> from Noumea - New Caledonia (22d16 S, 166d27E) UT+11
> email : papou@canl.nc    home page : http://www.chez.com/papou
> Association Caledonienne d'Astronomie : http://www.mygale.org/09/ascala=
/

I was very intersted in this feedback from the last Lewis orbit.=20

I have become quite facinated with decaying objects recently. This is
thanks to Alan Pickup and his Satevo program and predictions.=20
This last weekend I followed the last orbits of the Lewis satellite,
collecting element sets and running decay predictions. I took the last
element set from OIG for Lewis, for orbit 577, and pluged it into
STS-Plus and hey presto....the observations of Papou Millott agree to
within a few seconds of the direction, altitude and azimuth of the
decaying satellite.  I have included the STS-Plus output below.



Lewis Orbit 577 NORAD #24909


element set
Lewis                                            147 x 144 km
1 24909U 97044A   97271.44446403  .42558223  17556+1  79870-3 0 91500
2 24909  97.5423 169.9633 0002314 165.7839 194.2226 16.47663106  5777

Station Koutio 166.27E -22.13S
At  0 deg elev  9/28/1997 11:26:17 UTC range  1341.81 km	Azm 15.85	lat
-10.69S	long 169.73E

At 50 deg elev  9/28/1997 11:28:59 UTC range   184.54 km	Azm 65.76	lat
-21.79S	long 167.46E

(closest pass)
At 56 deg elev  9/28/1997 11:29:08 UTC range   171.72 km	Azm 103.02	lat
-22.41S	long 167.33E


The Los Angeles Times reported (from  the U.S. Space Command) the exact
re-entry to be 11:58 UTC as the spacecraft was heading north again still
on orbit 577. The exact location of re-entry was given as somwhere in
the South Atlantic off the coast of Antartica.

Facinating.

I guess my question would be, as a novice, how long do these things
generally stay up afer starting to burn up, as I am assuming Lewis was
doing over New Caledonia. This particular case would have Lewis burning
up for about 30 minutes or so (about a third of an orbit). Is this
normal?




Jeremy Ollerenshaw
jolleren@ix.netcom.com