China implements intensive tests in preparation for exploring Mars. A hydrogen-oxygen engine completed a 100-second ground test, and will be used for launching Long March 5 Y4, the fourth Long March 5 carrier rocket which will be used for China's first Mars exploration mission in 2020. Apart from the hydrogen-oxygen engine which completed the pre-launch test of 100 seconds, the development team has been testing engines of the same batch for up to over 500 seconds to test overall capabilities of the engine type for Long March 5, which will take part in multiple missions in 2020.