Author Topic: Soyuz-2.1v - Kosmos 2525 (EMKA) - Plesetsk - March 29, 2018 (17:38 UTC)  (Read 26674 times)

Offline Phillip Clark

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Following on from my message yesterday, still no new TLEs for the Blok I from the Cosmos 2525 launch, although the Satellite Situation Report continues to show it as being in orbit.
I've always been crazy but it's kept me from going insane - WJ.

Offline Phillip Clark

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The Block I has had two new element sets issued for April 28, so it is still chugging around up there.   I wonder why there was the four days gap in the data.
I've always been crazy but it's kept me from going insane - WJ.

Offline Phillip Clark

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I admit that this mission has been a bit of a disappointment, since there have been no manoeuvres of Cosmos 2525 to date.

The most recent orbital data for the mission are:

Cosmos 2525
May 17.714    96.632 deg      90.700 min     307-311 km

Blok I
May 17.605    96.636 deg      90.648 min     304-309 km
I've always been crazy but it's kept me from going insane - WJ.

Offline Phillip Clark

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Very small, but it looks as if there was a tweak to the Cosmos 2525 orbit yesterday.

May 23.241    incl - 96.633 deg      period - 90.682 min     altitude - 306-310 km    AoP - 126 deg
May 23.306            96.631                         90.695                          307-310                     88
I've always been crazy but it's kept me from going insane - WJ.

Offline Alter Sachse

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No manoeuvres of Cosmos 2525
March 29  96.64 deg 90.87 min 316 319 km
July    09  96.63       90.53        299 302

Offline Phillip Clark

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No manoeuvres of Cosmos 2525
March 29  96.64 deg 90.87 min 316 319 km
July    09  96.63       90.53        299 302

Just the very small manoeuvre which I reported on May 24.
I've always been crazy but it's kept me from going insane - WJ.

Offline Alter Sachse

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No manoeuvres of Cosmos 2525
March 29  96.64 deg 90.87 min 316 319 km
July    09  96.63       90.53        299 302

Just the very small manoeuvre which I reported on May 24.
Or it was inaccurate data ?

Offline Phillip Clark

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No manoeuvres of Cosmos 2525
March 29  96.64 deg 90.87 min 316 319 km
July    09  96.63       90.53        299 302
Just the very small manoeuvre which I reported on May 24.
Or it was inaccurate data ?

I don't believe so.   If you follow the argument of perigee - for example - before and after it is consistent with a tiny orbital change.   Also an error in the mean motion to give the orbital period would not result in the change in orbital eccentricity.

However, this manoeuvre is close to what I consider to be the limits of the TLE data.
I've always been crazy but it's kept me from going insane - WJ.

Offline Alter Sachse

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I thought he would raise his orbit or holding a certain level (to do his job).
But he falls and falls.

Offline Phillip Clark

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I thought he would raise his orbit or holding a certain level (to do his job).
But he falls and falls.

Agreed.   I had hoped for more.   I am assuming that there hasn't been a malfunction.
I've always been crazy but it's kept me from going insane - WJ.

Offline Alter Sachse

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No manoeuvres of Cosmos 2525
March 29  96.64 deg 90.87 min 316 319 km
July    09  96.63       90.53        299 302
July   28   96.63      90.45      295 299
« Last Edit: 07/29/2018 04:56 PM by Alter Sachse »

Offline Alter Sachse

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No manoeuvres of Cosmos 2525
March 29  96.64 deg 90.87 min 316 319 km
July    09  96.63       90.53        299 302
July   28   96.63      90.45      295 299
August 26 96.62     90.32    289 292
« Last Edit: 08/27/2018 11:32 AM by Alter Sachse »

Offline Phillip Clark

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The orbit is slowly decaying to one which will be Sun-synchronous.
I've always been crazy but it's kept me from going insane - WJ.

Offline Phillip Clark

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The orbit of Cosmos 2525 has now decayed to an altitude that means that the orbit is Sun-synchronous:

Sep 18.123    96.617 deg   90.176 minutes   281 km   285 km   127 deg (AoP)

It is possible that the Russians will start small orbit-maintenance manoeuvres to keep the orbit Sun-synchronous.   Of course they might simply let the satellite continue its slow orbital decay.
I've always been crazy but it's kept me from going insane - WJ.

Offline Phillip Clark

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So far the Cosmos 2525 orbit has continued its slow decay.
I've always been crazy but it's kept me from going insane - WJ.

Offline Alter Sachse

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So far the Cosmos 2525 orbit has continued its slow decay.
Maybe it's a satellite without an engine ?

Offline Phillip Clark

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I believe that there was a very small manoeuvre on May 23 when the orbital period increased from 90.682 minutes to 90.695 minutes.
I've always been crazy but it's kept me from going insane - WJ.

Offline B. Hendrickx

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Assuming Kosmos 2525 is VNIIEM's Zvezda satellite (which we have every reason to believe based on evidence presented earlier in this thread), it has a thermal catalytic propulsion system of OKB Fakel called K50-10.5. That at least was the plan in 2015 when this paper was published (about the selection of engines for Zvezda):

http://ihst.ru/files/pdfs/Korolevskie-chteniya-2015-Materialy.pdf
(see p. 59-60)

At the time the objective was to place Zvezda into a nearly circular 500 km Sun-synchronous orbit. According to the article, the engine unit was to be used to correct orbit insertion errors, maintain the working orbit throughout the satellite's lifetime and ensure proper phasing between satellites in a constellation. The mass of the engine unit should not exceed 30 kg. It was to have a total impulse of not more than 2 t.s , a thrust of between 5 mN and 1N and use monopropellant. Four types of engines were evaluated and in the end the choice fell on Fakel's K50-10.5. This, by the way, is the same engine that is carried by Cosmos-2519 (according to data from Fakel).


Offline Star One

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Assuming Kosmos 2525 is VNIIEM's Zvezda satellite (which we have every reason to believe based on evidence presented earlier in this thread), it has a thermal catalytic propulsion system of OKB Fakel called K50-10.5. That at least was the plan in 2015 when this paper was published (about the selection of engines for Zvezda):

http://ihst.ru/files/pdfs/Korolevskie-chteniya-2015-Materialy.pdf
(see p. 59-60)

At the time the objective was to place Zvezda into a nearly circular 500 km Sun-synchronous orbit. According to the article, the engine unit was to be used to correct orbit insertion errors, maintain the working orbit throughout the satellite's lifetime and ensure proper phasing between satellites in a constellation. The mass of the engine unit should not exceed 30 kg. It was to have a total impulse of not more than 2 t.s , a thrust of between 5 mN and 1N and use monopropellant. Four types of engines were evaluated and in the end the choice fell on Fakel's K50-10.5. This, by the way, is the same engine that is carried by Cosmos-2519 (according to data from Fakel).

Well if it does have this engine why has it hardly been used?

Offline Alter Sachse

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2 options:
- it is not the satellite ("Zvesda")
- engine does not work.

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