Mix-ups about Mars '96 decay(s)

Ed Cannon (ecannon@mail.utexas.edu)
Wed, 10 Sep 1997 12:57:03 -0400

Hello SeeSat folks!

I don't remember seeing anything about this before, and I hope it's
close-enough-to-topic for SeeSat.  I'm writing about it because of 
the contradictory information I encountered regarding the decay of 
various parts of Russia's Mars '96 launch last November.  

On a Federation of American Scientists Web pages -- home page is 
http://www.fas.org -- I found a hyperlink to a news story reporting 
observations of, allegedly, the Mars '96 space probe's re-entry:


The observed (alleged) re-entry occurred over Chile and/or Bolivia.  
The story gives November 16, 1996, as the re-entry date.  Since the 
launch took place on Nov. 16 at 20:48:53 UTC, so I tend to think the 
story has the date wrong -- or it was some other object.  Or else 
OIG and/or the Russians have some numbers confused or missing.

On a Mars '96 Web page discussing the decay point of the Mars '96
Block D-2,


they list several OIG elsets, e.g. the last one:

1 24656U 96064A   96323.01130778  .13328068  12842-4  45328-4 0   133
2 24656  51.4998  11.2010 0005797 231.1092 129.2833 16.58057739   180

and state that using those along with Russian data (also listed on
that Web page) they determined that the Mars '96 Block D-2 decayed 
over the Pacific Ocean between Easter Island and Chile between 1:10 
and 1:20 a.m. UTC Nov. 18, 1996.  On the same page they also state 
that the *spacecraft* separated from the Block D-2 several orbits 
before the Block D-2 decayed.  (In another place they include the 
Block D-2 among several objects that together comprised the "payload".  
I didn't find anything on that site about when the Mars '96 space 
probe itself decayed, which seems a notable omission since they make 
a point that it separated from the Block D-2.)  Note the catalog 
number 24656 and the ID 96064A are applied to the Block D-2.

The OIG weekly report for Nov. 14-20, 1996 (week 47), lists #24656 as 
96-064A and says it decayed on Nov. 18, 1996.  However, the July 1997 
Satellite Situation Report (Mike McCants' format, except with the RCS 
column omitted) has this listing:

  Cat Design   Name              Country  Launch   Decay/Per Incl  
24656 96-064B  MARS 96 R/B           CIS  11/16/96 03/18/97  51.5

So, was #24656 the same as 96-64A or 96-64B?  Did 24656 decay on Nov. 
18, 1996 UTC, or March 18, 1997?  Was 24656 the Block D-2, the space 
probe itself, or some other part of the Mars '96 rocket-payload 
system?  Which object decayed over Bolivia/Chile?  When did that 
decay really occur?  Was it really the Mars '96 space probe itself 
or possibly the Block D-2?  (The point of the news story about the 
observed decay is to claim that the fiery decay of the plutonium-
powered Mars '96 space probe demonstrates that it's too dangerous to 
launch the Cassini probe.)  Did some Mars '96 objects never get into 
the OIG catalog?  Etc., etc.  

(Note to Alan Pickup:  I don't have your relevant late 1996 decay 
reports easily available here and now.  On your Web archive of 1997 
reports, the only decays listed on late March 17 or March 18 are a 
Mir debris and a Pegasus debris.) 


Tuesday evening 9/9/97 one-power observations (from the Univ. of 
Texas at Austin campus -- not a dark-sky site!):  Cosmos 2333 Rk 
(96-51B/24298), Cosmos 1437 Rk (83-3B/13771), HST (90-37B/20580), 
and Cosmos 2219 Rk (92-76B/22220).


Ed Cannon
Austin, Texas, USA
30.3086N, 97.7279W, 165m