Long March

The third launch of China’s heavy-lift Long March 5 rocket successfully delivered its satellite payload to orbit Friday, validating engine design changes after a failure on the Long March 5’s second flight, and clearing the way for the launch of a Chinese Mars rover and lunar sample return mission in 2020.

China’s Long March 5 rocket — the country’s most powerful launcher — is set for its third flight Friday on a critical validation mission after a core stage engine failure doomed a launch in 2017 and forced a two-and-a-half-year investigation and redesign effort.