The engines for China's largest carrier rocket Long March 5 Y-4 completed its final test on Sunday, about three weeks after its predecessor Y-3 launched from Wenchang Space Launch Center in south China's Hainan Province, suggesting another booster is one step closer to joining China's largest carrier rocket family.

Read more: China launches its largest carrier rocket Long March-5 Y3

The super-cold liquid hydrogen and liquid oxygen propellants, also known as the rocket's "hearts," are now ready to enter the final assembly stage of the rocket, CCTV reported.

The Y-4 carrier rocket will be responsible for China's first independent interplanetary mission in 2020, sending an orbiter and rover to Mars.