The Proton Second stage is a medium stage. It is the second stage of the Proton rocket. It is also the most powerful second stage in the game, and is recommended for heaviest payloads (such as the Station Refuel Silo) in both sandbox and missions.

Trivia

The text in this second stage says "Протон", which is "Proton" in Russian.

The second stage as part of the proton rocket.

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