Re: Cosmos 2387

From: Phillip Clark (
Date: Tue May 14 2002 - 01:44:12 EDT

On Mon, 13 May 2002, Steve Newcomb wrote:
> I was wondering why this recently launched sat is not in a typical orbit.

I did a piece which I submitted to Jane's Defence Weekly a couple of weeks
ago about this.

The Russians no longer have a stockpile of these satellites, and therefore
when they fly they have had increasingly long lifetimes.   The original
Kobalt-class satellites had lifetimes of ~60 days typically, but during
the mid/late 1990s this started to increase, to the point that Cosmos 2377
last year flew for just over 133 days - a record for this class of

Normally these satellites fly with perigees of 170-180 km and apogees in
excess of 300 km, but the last two manoeuvres of Cosmos 2387 have resulted
in perigees of 240 km or more.

Having the higher perigee means that orbital decay is slower (although
reducing ground resolution) and thus the fixed amount of propellant needs
to be used at a slower rate.   So I am wondering whether Cosmos 2387 will
be flying for even longer than Cosmos 2377 last year.

A problem with the satellites is that they still have only the two
side-mounted film return capsules to be used while the main satellite
remains in orbit, and then at the end of the mission the descent module is
recovered with the camera system intact (hopefully !) and the remaining
used film.   With the longer lifetimes, of course it means that there is a
longer wait to get the film back for analysis.

Guess that this has wandered a little off-topic for SEESAT !

Phillip Clark

Phillip S Clark                                  Flat 2 Wellington House
Molniya Space Consultancy                        Castle Hill Passage
Compiler/Publisher, Worldwide Satellite          Hastings
    Launches                                     E Sussex  TN34 1PG

The only way to comprehend what politicians say and do is to make to basic
assumption that their brains were surgically removed before they entered
politics.   (My own philosophy.)

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