Complex sentence: The rocket then continued to operate properly, with the propellant system rerouting the fuel to the other engines and the shutoff engine didn't disintegrate due to the heat as some had predicted due to lack of cooling propellant running around it.
Split into simpler sentences: The rocket then continued to operate properly, with the propellant system rerouting the fuel to the other engines. The shutoff engine didn't disintegrate due to the heat as some had predicted caused by a lack of cooling propellant running around it.