The Moon Wanders Out

In 2040, a rogue gas planet breaks into the solar system and will hit the sun to produce a flare 100 years later. In order to allow more people to survive, the coalition government implements two plans at the same time, the "Leap Plan" and the "Underground City Plan". Plan 1 plans to design 3,000 planetary engines to allow some people to go to the moon, and then push the moon out of the flare area. Plan 2 is to build an underground city 3 to 5 kilometers underground to ensure the survival of people on the earth. I can't make it up anymore, I'm so embarrassed by making it up