Re: Mir (16609) and Soyuz T-15 (16643)

From: Bob Christy (
Date: Fri Mar 11 2011 - 09:16:53 UTC

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    Hello All
    The fact that manoeuvres by Salyut 7 and Mir were used to minimise Soyuz 
    T-15's fuel consumption was 'well known' at the time (at least by those 
    of us who were tracking them). Being pre-internet, it's one of those 
    memories that have faded from the collective conscience because it was 
    only set down in peoples' private observation logs and the odd 
    narrowly-circulated journal.
    Prior to the transfer from Mir to Salyut, from recollection, there was a 
    period when two stations kept a distance from each other. Our assumption 
    was that the separation ensured that only one station could be above the 
    horizon at any time. This would avoid radio inteference because they 
    were operating at some common frequencies.
    Marcia Smith wrote detailed descriptions of the manoeuvres involved in 
    both inter-station journeys in Part 1 of the US Senate Report "Soviet 
    Space Programs: 1981-1987" (pages 70-75). It was published May 1988.
    Here are summaries of the visible passes from Lincoln, UK at the time of 
    Soyuz T-15's journey back from Salyut 7 to Mir. The one on Jun 26 should 
    be read in conjunction with Ted's report timed four hours later (see 
    note at bottom of this mail):
    1986 Jun 25
    MIR noted (mag 0) at 2238 UTC - track SW-SE,
    SALYUT 7 (also mag 0) was two minutes behind - identification based on 
    Doppler shifted radio signal,
    SOYUZ T-15 was leading SALYUT 7 by 4.5 seconds in time and was slightly 
    lower in elevation (about 30 km distance).
    1986 Jun 26
    Seen between 22:50 and 22:55 UTC - track W-SE, two objects, both mag 0, 
    separated by about 30 seconds of time - approx 200 km (Soyuz now docked 
    with Mir).
    [Hindsight - Salyut 7 was probably the leader]
    1986 Jun 27
    Approx 21:40 - low in SE, MIR (mag -0.5) was 2 minutes behind SALYUT 7 
    (mag 0).
    Approx 23:15 - high in S, MIR measured as 4 minutes behind SALYUT 7.
    [NOTE - the difference in time separation between the two observations 
    above is maybe a perspective effect due to the low elevation of the 
    first observation, four minutes is the better measurement]
    1986 Jun 29
    Timed at 22:20:00 and 22:32:35 respectively as they bisected the line 
    between Altair and Vega, MIR was 12.6 minutes behind SALYUT 7.
    1986 Jul 1
    Separation now 20 minutes.
    Bob Christy
    On 11/03/2011 06:57, Ted Molczan wrote:
    > ..............I managed to get home from the
    > airport just in time to drop my suitcase and invite a neighbour to join me on the roof of my apartment building to observe. We
    > spotted Mir first, rising in the west (June 26, 02:56 UTC). Several minutes later, we spotted Salyut 7 in the west, and as it became
    > better illuminated we easily spotted the Soyuz leading Salyut 7 by something like 10 s in time.
    > Ted Molczan
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