An Atlas V carried the SBIRS-GEO 4 military satellite in January 2018. The Atlas V's launch of NASA's InSight to Mars in 2018 was the first interplanetary probe to depart from the U.S. West Coast. In August 2018, a Delta IV Heavy launched Parker Solar Probe, NASA's solar space probe that will visit and study the sun's outer corona in August 2018. It was also the Delta IV Heavy with a Star-48BV kick stage, and the highest-ever spacecraft velocity. The company launched the final Delta II rocket, carrying ICESat-2 from Vandenberg Air Force Base SLC-2 on 15 September 2018. This marks the last launch of a Delta family rocket based on the original Thor IRBM. On 22 August 2019, ULA launched its last Delta IV Medium rocket for the GPS III Magellan project. An Atlas V carried Boeing's Starliner Orbital Flight Test (OFT) mission for NASA in December 2019.