China developed the powerful rocket, which is designed to carry 25 tons of payload into low orbit, with the aim of launching a Mars probe in 2020.
But the Long March 5 project, originally announced in 2001, suffered lengthy delays due to funding challenges and difficulties in developing new technologies for the first Chinese launcher to fully use liquid propellant.
A second test of the rocket failed in 2017, threatening to delay the country's push to become a leading space power.
Earlier this year, China completed its first public test of a Mars lander, keeping the country on track for an unmanned exploration mission to the red planet next year.
The country was late to the space race -- it didn't send its first satellite into space until 1970, just after the United States put the first man on the moon.
But in the decades since, China has pumped billions of dollars and other resources into research and training. In addition to the Mars mission, China has been actively pursuing lunar exploration.
The Chang'e-4 lunar probe successfully touched down on the far side of the moon in January, a historic first and major achievement for China's space program.
In 2020, the next lunar mission is due to land on the moon, collect samples and return to Earth, while preliminary plans are underway for a manned lunar mission in the 2030s. If successful, China would become only the second country, after the United States, to put a citizen on the moon.
It also plans to launch a 20-metric-ton space station around 2022.
CNN's Steven Jiang and Lily Lee contributed to this report. CNN's Tara John wrote from London.
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