Re: Sea Launch Second Stage
Phillip Clark (psclark@dircon.co.uk)
Thu, 1 Apr 1999 07:04:06 +0100 (BST)
There are two primary launch proifiles for the Zenit-3SL, both of which
have the first two stages of the vehicle (essentially the Zenit-2
launcher) sub-orbital.
First profile is for the Block DM-SL to perform low, parking orbit
injection and then re-start to enter geosynch transfer orbit where the
payload is deployed: since all of the propellant is used for these two
burns it maximises the payload mass, although the payload has to pergorm
its own injection to geosynch orbit.
Second profile is for the DM-SL stage to perform three burns: at the
apogee of the GTO the stage ignites for a third time to circularise the
orbit at GEO. This reduces the mass of the payload which can be
launched, but means that the payload has to perform only a small
manoeuvre to enter its operational orbit (like the Russian domestic GEO
launches).
There are variations on these themes, with delayed second burns and
delayed third burns to optimise the GEO injection longitude. Plus one
assumes that the third stage can be used to deploy the satellite in a
super-GTO but lower than GEO, as has happened on the commercial Proton-K
missions (with the exception of INMARSAT-3 2 which was very light for a
Proton launch).
Phillip Clark
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Phillip S Clark 25 Redfern Avenue
Molniya Space Consultancy Whitton
Compiler/Publisher, Worldwide Satellite Launches Middx TW4 5NA
U.K.
Specialist in "space archeology" - the older and more obscure the more
interesting it is !
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