Complex sentence: The "Mars Surveyor 2001 Orbiter", renamed "2001 Mars Odyssey", was launched April 7,2001 reached Mars on October 24,2001 and after a few months of aerobraking, began mapping the planet on February 19,2002.
Split into simpler sentences: The "Mars Surveyor 2001 Orbiter", renamed "2001 Mars Odyssey", was launched April 7,2001 reached Mars on October 24,2001. After aerobraking from October 2001 until January 2002, "Mars Odyssey" began mapping the planet on February 19,2002.