Complex sentence: The largest company of Russia's space industry is RKK Energiya, the country's main human spaceflight contractor, the lead developer of the Soyuz-TMA and Progress spacecraft and the Russian end of the International Space Station.
Split into simpler sentences: The largest company of Russia's space industry is RKK Energiya. It is the country's main human spaceflight contractor, the lead developer of the Soyuz-TMA and Progress spacecraft and the Russian end of the International Space Station.