Podkayne of Mars by Robert A. Heinlein

Podkayne of Mars is just a cute little young adult story about a teenaged girl who gets caught up in events a bit beyond her control and understanding, very similar to Red Planet. Podkayne (named after a hero of Martian history) wants to be a space pilot someday when she grows up. Her parents are very accomplished professionals who have unexpectedly been burdened with three extra babies due to a mistake at the creche just as they are about to take her and her brother, Clark, on a family vacation to Earth, and she is horribly disappointed when the trip is cancelled.

But Podkayne's Uncle, Tom (Heinlein was obviously having some fun with this name, as Tom is a black man of Maori descent), a Senator at large from Mars, saves the day when he browbeats the creche administrators into providing an all-expense-paid trip for himself and the two teens to Venus and Earth. But Tom has another purpose in making the trip; he has been named ambassador plenipotentiary to the solar system council meeting that's soon to take place on Earth, and he hopes to throw his political opponents off the scent by disguising his trip as a pleasure jaunt with his young relatives.

Podkayne is an attractive young thing, and she soon has the crew of the ship wrapped around her little finger, conning them into showing her all around the control room and teaching her differential equations used in astrogation. She has her pick of the young officers to dance with, and makes some friends among the passengers, as well, though she soon finds out that some of them are two-faced - harboring prejudices about Martians, who are the descendents of convicts used for forced labor on Mars.

The political forces opposing Tom's mission are not totally flummoxed by his ploy, and one faction uses his nephew, Clark, to smuggle a bomb on board the ship. Clark is a bit smarter than the average adolescent, however, and realizes something is wrong with the picture, so he disassembles (dissembles, too) and disarms the bomb, tucking it away for future use, perhaps. When the trio arrive on Venus, they are entertained by the planet's governor, and his son becomes quite entranced with Podkayne, squiring her about the planet in style.

Their fun is spoiled when another one of the factions abducts first Clark, then Tom, then Poddy, and they are forced to use all their wits to escape intact. Unfortunately, the story stops at Venus, so we don't get to experience Earth with Poddy. I wonder if Heinlein had intended to finish the story in a sequel?