Complex sentence: The exterior of the SLA was covered by a layer of cork nearly 1 mm thick and then painted white, the cork insulating the Lunar Module from atmospheric frictional heat generated durning launch and ascent.
Split into simpler sentences: The exterior of the SLA is covered by a layer of cork nearly 1 mm thick and then painted white. The cork insulates the Lunar Module from atmospheric frictional heat generated durning launch and ascent.