Re: acceleration of Kosmos 1867

Kurt Jonckheere (kjonckheere@unicall.be)
Fri, 17 May 1996 11:49:58 +0000

I wrote:
>87- 60 A = 18187 = Cosmos 1867
>93-06-29 LB         almost S, mag 5   
>93-10-17 TC         S, mag +2.5, u    
>94-05-11 TC         S, mag +6.5       
>96-05-15 KJ   8.0                     
>96-05-15 TC   8.30  AA, mag +3        
>Started flashing!! 

Tristan wrote:
>As I saw Kosmos 1867(87-60A/18187) flashing yesterday, I was curious to find
>something back in recent elements of this object.  
Tristan indeed found back an jump in Mean Motion at the end of 1995.
>87060_A
>1 18187U 87060  A 95343.79661940  .00000034  00000-0  13186-4 0  3615
>2 18187  65.0049 252.6079 0012281 267.1725  92.7947 14.30093189439503
>87060_A
>1 18187U 87060  A 96 03.97149092  .00000282  00000-0  14748-3 0  3684
>2 18187  65.0037 182.2685 0013300 272.7740  87.1818 14.30105764443102

I just run my program and created a graph of the orbital elements
since May 1992.

It is very obvious that there were TWO jumps in Mean Motion during 
the last years:
The first one happened between 94 Aug 18 and 22.  Semi major axis
decreased suddenly from 7169.726 to 7169.623 km, a jump of 
100 metres.
The second one is the one Tristan mentioned.  It occured between 
95 Dec 21 and 96 Jan 3.   An decrease of 40 metres.

I cannot detect the date of the jump better because of lack of
orbital elements.

When I compare these jumps with those happening with rockets
the difference is that for a rocket it can take several days 
or weeks for the elements to become stable again.  For this rocket
there is a very sudden jump; before and afterwards the semi
major axis is very stable (slowly decreasing lineair).

As you can see from the PPAS-extract we have no observations in
our Database to conclude what jump caused it to accelerate and
how it accelerated.  It would be very interesting to compare the
acceleration of a payload to a rocket!  So keep on observing!

Latest elements:
1 18187U 87060  A 96137.11789093  .00000007  00000-0  27536-5 0  4103
2 18187  65.0080 170.2565 0016062 278.7097  81.2167 14.30107991462144

I asked Bjoern and Bart to make the graph available via the net.


Happy observing and... don't forget 96- 17 B too!!,

Kurt J


----------------------------------------------------------------------------
          Kurt Jonckheere (kjonckheere@unicall.be)   51.2 N  2.9 E 
      observations collector for the Belgian Working Group Satellites: 
  Send your observations of flashing satellites, preferrably in the correct
       PPAS format to obs@physics.oxford.ac.uk or obs@physics.ox.ac.uk
                I Dreamed I Dream      --       Sonic Youth
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