Author Topic: Soviet US-P electronic intelligence satellites  (Read 596 times)

Offline jcm

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Soviet US-P electronic intelligence satellites
« on: 08/08/2017 02:02 AM »
There are comparatively few historical mysteries left from the glory days of Soviet space.
But one of them, as far as I now, is the mysterious series of  post-mission distintegrations of the US-P ELINT ocean recon satellites (e.g. Kosmos-838, Kosmos-1220, Kosmos-1461 etc) . Last I heard, some years ago, it was still unclear whether these
were commanded destructions, accidental activation of a command destruct system, or explosion of residual propellant. But perhaps the answer is now out there and I've missed it? Or one of our Russian readers has contacts in Kometa who can provide the answer?

Anyone?
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Jonathan McDowell
http://planet4589.org

Offline B. Hendrickx

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Re: Soviet US-P electronic intelligence satellites
« Reply #1 on: 08/09/2017 11:49 AM »
To the best of my knowledge, the satellite designers themselves have still not revealed why many of the satellites broke up. Even a detailed history of the EORSAT/RORSAT program published in 2002 did not shed any light on this, nor did a Kometa history published several years later.

According to an analysis published in "Novosti kosmonavtiki" (2/2002 issue) the most likely explanation is that the satellites broke up due to the explosion of residual propellant or the pressurized buses, which carried chemical storage batteries (unlike the nuclear-powered RORSATs, EORSATs had solar panels). This conclusion was mainly based on the fact that the break-up rate went significantly down after the end-of-mission maneuver placed the satellites in lower rather than higher orbits (beginning in 1986), as a result of which the orbits decayed much faster. Apparently, this change was deliberately made to ensure that the satellites re-entered before they had a chance to break up (although some still did despite that change). In other words, there was no self-destruct mechanism on the satellites.

Interestingly, when the last EORSAT (Cosmos-2421) broke up in 2008, the Russian Ministry of Defence was forced to come up with an explanation when some of the debris started threatening the ISS. After initially denying that the satellite had broken up, it later issued a statement that the satellite's solar panels had probably been hit by a piece of space debris...   

Offline jcm

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Re: Soviet US-P electronic intelligence satellites
« Reply #2 on: 08/09/2017 01:17 PM »
To the best of my knowledge, the satellite designers themselves have still not revealed why many of the satellites broke up. Even a detailed history of the EORSAT/RORSAT program published in 2002 did not shed any light on this, nor did a Kometa history published several years later.

According to an analysis published in "Novosti kosmonavtiki" (2/2002 issue) the most likely explanation is that the satellites broke up due to the explosion of residual propellant or the pressurized buses, which carried chemical storage batteries (unlike the nuclear-powered RORSATs, EORSATs had solar panels). This conclusion was mainly based on the fact that the break-up rate went significantly down after the end-of-mission maneuver placed the satellites in lower rather than higher orbits (beginning in 1986), as a result of which the orbits decayed much faster. Apparently, this change was deliberately made to ensure that the satellites re-entered before they had a chance to break up (although some still did despite that change). In other words, there was no self-destruct mechanism on the satellites.

Interestingly, when the last EORSAT (Cosmos-2421) broke up in 2008, the Russian Ministry of Defence was forced to come up with an explanation when some of the debris started threatening the ISS. After initially denying that the satellite had broken up, it later issued a statement that the satellite's solar panels had probably been hit by a piece of space debris...   

Thanks. The argument about the changed end of mission behaviour is plausible but not necessarily definitive; it would be really nice if the designers did tell us one of these days..
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Jonathan McDowell
http://planet4589.org

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