The Martian Chronicles is about people confronting a new world. But will they change this world or will they themselves change? Throughout the book we see examples of things changing: the rocket changes winter into summer ("Rocket Summer"), Martians change from looking like one thing to looking like another. But then there are also examples of people trying to stop change, like Yll killing off the human explorers just to preserve his unhappy marriage. In The Martian Chronicles, change may not be good—but it's definitely unstoppable.
In The Martian Chronicles, change is presented as an inevitable effect of life—it's neither good nor bad.
Change is always presented as dangerous in The Martian Chronicles. The best thing the Martians did was to stop advancing their technology.