Just read the "Martian Chronicles" by Ray Bradbury? This character list will help you keep all the details straight, as well as provide a glimpse into their significance in the story.
"Ylla," "The Earth Men," and "The Third Expedition"
Each section of The Martian Chronicles has its own characters. The characters in the first three sections appear here.
Mr. K (Yll) -- He thinks his wife's dreams are silly, if not dangerous.
Ms. K (Ylla) -- She has dreams about the arrival of a man from another planet, stepping out of a rocket. She represents the tired American housewife of the early Cold War era.
Nathaniel York -- He is the captain of the first mission from Earth to Mars. He appears in Mrs. K's dreams, causing friction between her and her husband, and leading to his own death.
The Earth Men
Captain Williams -- He is the captain of the second mission from Earth to Mars. His intellect helps him figure out, before his fellow travelers do, that they have all been lured into an asylum.
The Third Expedition
Samuel Hinkston -- He is the 80-year-old archeologist traveling with the third mission from Earth to Mars. He is intrigued by the American-looking town right in the middle of Mars, and he comes up with outlandish reasons for the town to be there.
Captain John Black -- He leads the third mission to Mars, and he believes that this strange American town is nothing but a trap. However, seeing his family lures him to his demise.
"--And the Moon be Still as Bright"
These are the characters in the fourth section of The Martian Chronicles.
Captain Wilder -- He is the leader of the fourth mission from Earth to Mars, and he is squarely on the fence between the opposing opinions that Mars should be at the disposal of the new settlers from Earth, for all of their needs, and the idea that the incoming settlers should respect the Red Planet. Spender and Parkhill (see below) represent those opposing views. Because he tries to help Mars stay in its pristine condition, he gets sent to explore other planets.
Sam Parkhill -- He is eager to take Mars and subjugate its resources to the needs of the new settlers. He even treats his new surroundings cavalierly, firing his weapons at the Martian buildings. Later, he opens a hot dog stand for the new settlers from Earth.
Jeff Spender -- He is the archeologist for this mission, and he is deeply troubled about the effects that colonization will have on the Martian environment. After he goes off by himself to explore the planet, he decides to murder the other crew members so that Mars will be preserved.
Hathaway -- He is the geologist and medical doctor for this mission. He stays, with his family, on Mars even when most of the colonists return home after the outbreak of war. After his family dies, he constructs robots to replace them.
The 5th Section
The Green Morning
Benjamin Driscoll -- He is one of the Martian Chronicles characters with a strong reaction to the environment -- he almost has to go back to Earth because of the thinness of the air. He plants trees everywhere to build up the oxygen levels.
Muhe Ca -- He is a Martian who may or may not be real -- he may be from a different dimension.
Toma's Gomez -- He is one of the earliest settlers.
Way in the Middle of the Air
Mr. Teece -- He is a storekeeper -- and a racist who has taken part in hangings, and when he finds out that blacks want to colonize Mars too, he is scandalized.
Belter and Silly -- They are two black men who work for Mr. Teece. Belter owes Mr. Teece $50, so the store owner won't let him leave until the debt is paid. Silly almost does not get to leave, because he has signed a contract to work for Mr. Teece for a fixed time period, but Mr. Teece gives in and lets him leave.
William Stendahl -- He loves fantastic literature along the lines of Lewis Carroll and Edgar Allan Poe. On Earth, those authors had been censored.
Garrett -- He is one of the Investigators of Moral Climates, and he investigates Stendahl's house (Usher, a clear allusion to Poe) using a robot copy of himself -- and later goes himself.
The 6th Section
Tom -- He isn't actually who he claims to be -- he's a Martian who has taken on Tom's form, because he wants the love that Tom's parents want to give to their dead son. The Martian desires love and takes the place of this dead Earthling.
LaFarge and Anna -- They are "Tom's" parents. LaFarge figures out that their "son" is really a Martian, but he never tells his wife.
The Off Season
Elma -- She is Sam Parkhill's wife and gets a great deal of entertainment at the ways he bungles life on the Red Planet.
The Long Years
Williamson -- He travels with Captain Wilder to Jupiter and Pluto; upon their return to Mars, he is in charge of finding out whether or not Hathaway's family is dead or alive.
The Million-Year Picnic
Dad -- At one time the governor of Minnesota, he has come to Mars to start a new chapter -- he even burns a map of the Earth when they get there.
Timothy -- He is the oldest son, and he takes this job to heart. He easily moves into helping his dad in bringing about an easy adjustment to Mars for his younger brothers.