Re: Impact on Met 3-1 r?

Peter Wakelin (
Fri, 27 Dec 1996 09:32:12 +0000

In message <>, Ron Dantowitz
<> writes
>While tracking Met 3-1 r (#16194 / 85100  B) the satellite was "missing",
>despite the elements being only 9 days old (still quite fresh, esp for a
>"dead" object).  Our tracking telescopes were locked onto the correct
>coordinates, but the satellite was TWELVE+ seconds late! (12.2 secs late).
>In almost two years of tracking we have only seen this on active sats (ie
>Mir, STS, and "dark" sats).  I haven't yet checked the element archives, but
>has anyone else noticed this?  I have found the elements of 99%++ of all
>other sats to be quite excellent... this anomoly was unusual, to be sure.
This object is close to 13th order resonance and its gain in energy is
sufficient to offset the loss due to drag.  Change half ndot to zero and
it will be on time.  Mean motion is unchanged over the last several
months yet two-line elements consistently give a positive half ndot.
However, this cause is unlikely to account for the full 12 seconds over
a 9 day period.
>Other notes: Just discovered it is possible to see Mir by moonlight alone.
The average full moon is 14.5 magnitudes dimmer than the sun so it seems
reasonable to assume that Mir will be 14.5 magnitudes dimmer when
illuminated by the full moon, ie around mag 13 which is sufficient to be
visible in moderate aperture telescopes.

>Also: Does anyone have any info on Cos 1766?  It appears physically larger
>than its 6m Molczan # would indicate.  It was HUGE.
>Cosmos 1766 is an Okean so should have similar optical characteristics.

Peter Wakelin