There's is a company which has a very big sea launch platform its name is Sea launch it has a long history they are in operations since the 1990s more than 30 launches Russia's energia and boeing used to own it recently Russia's S 7 airlines they bought it it was in US earlier now in Russia it's a huge rig like oil rigs it also has a support ship it used to launch the zenit rocket which is designed by Ukraine's Yuzhnoye design bureau they manufacture them some stages its also a fact that they are the ones behind India's SCE 200 engine its their design modified by ISRO.

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This is a very old design and it's a huge structure it's last launch happened in 2014 but it failed in 2013 served as a death nail for the platform no launches so far after 2014 and because of Russia and Ukraines issues using the zenit launch vehicle could be controversial so it will remain at the port for a few years Russia is making it's Soyuz 5 rocket which is planned to launch on this platform not so soon, planned for 2025 so it will remain idle for a few years under maintainance maybe.

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So this is sea launch sounds very lucractive launching from equator but lots of complications involved getting the rocket on the platform is a challenge with a crane or ship every stage saperately then integrate on board managing the entire platforms center of gravity and center of mass or it would be unstable weather issues in general lot of pre planning required to avoid potential cyclones and bad seas if the rocket uses cryogenic fuel then keeping the fuel is a challenge. lot of energy consumption 1st the support people have to work on the barge then hp on to a seperate ship and move away ship has to be actively stabilised too much extra work really makes you think if it's worth it if it was a missile platform.

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its definitely worth because you can conduct launches and tests secretly but is it worth as a rocket launch platform if you see Russia's and China's geography then they are corced to develop such a platform because their stages are dropped on land and many inclinations difficult sometimes dropped near some villages, why can't we take our rocket over Sri Lanka? because if this same reason PSLV stages might fall over Sri Lanka Russia and china are forced to develop this but India has such a big coastline west coast east coast both are quite open and we can utilize this easily you may think that a barge launch perfect for the SSLV but we have a good land site and a land-based port will always be cheaper than a sea launch port its not a easy task especially since we haven't made one keeping stable using thrusters also important or might launch the wrong way since we already have a good site its always better to use it will be cheaper as well to make and if an anomaly takes place just incase maybe a explosion or some failure than replacing a land launchpad will be cheaper and also take less time.