Complex sentence: Werner Karl Dahm (16 February 1917-17 January 2008) was an internationally recognized rocketry pioneer whose work in Germany and the United States who made important contributions to the nation's ballistic missile programs and its manned and unmanned rocket programs.
Split into simpler sentences: Werner Karl Dahm (16 February 1917-17 January 2008) was a rocketry engineer in Germany and the United States. Werner K. Dahm was an internationally recognized rocketry pioneer whose work in Germany and the United States who made important contributions to the nation's ballistic missile programs and its manned and unmanned rocket programs.